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http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Python
Python
  import random   board = [[" " for x in range(8)] for y in range(8)] piece_list = ["R", "N", "B", "Q", "P"]     def place_kings(brd): while True: rank_white, file_white, rank_black, file_black = random.randint(0,7), random.randint(0,7), random.randint(0,7), random.randint(0,7) diff_list = [abs(rank_white - rank_black), abs(file_white - file_black)] if sum(diff_list) > 2 or set(diff_list) == set([0, 2]): brd[rank_white][file_white], brd[rank_black][file_black] = "K", "k" break   def populate_board(brd, wp, bp): for x in range(2): if x == 0: piece_amount = wp pieces = piece_list else: piece_amount = bp pieces = [s.lower() for s in piece_list] while piece_amount != 0: piece_rank, piece_file = random.randint(0, 7), random.randint(0, 7) piece = random.choice(pieces) if brd[piece_rank][piece_file] == " " and pawn_on_promotion_square(piece, piece_rank) == False: brd[piece_rank][piece_file] = piece piece_amount -= 1   def fen_from_board(brd): fen = "" for x in brd: n = 0 for y in x: if y == " ": n += 1 else: if n != 0: fen += str(n) fen += y n = 0 if n != 0: fen += str(n) fen += "/" if fen.count("/") < 7 else "" fen += " w - - 0 1\n" return fen   def pawn_on_promotion_square(pc, pr): if pc == "P" and pr == 0: return True elif pc == "p" and pr == 7: return True return False     def start(): piece_amount_white, piece_amount_black = random.randint(0, 15), random.randint(0, 15) place_kings(board) populate_board(board, piece_amount_white, piece_amount_black) print(fen_from_board(board)) for x in board: print(x)   #entry point start()  
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Fortran
Fortran
!----------------------------------------------------------------------- ! gjinv - Invert a matrix, Gauss-Jordan algorithm ! A is destroyed. ! !___Name_______Type_______________In/Out____Description_________________ ! A(LDA,N) Real In An N by N matrix ! LDA Integer In Row bound of A ! N Integer In Order of matrix ! B(LDB,N) Real Out Inverse of A ! LDB Integer In Row bound of B ! IERR Integer Out 0 = no errors ! 1 = singular matrix !----------------------------------------------------------------------- SUBROUTINE GJINV (A, LDA, N, B, LDB, IERR) IMPLICIT NONE INTEGER LDA, N, LDB, IERR REAL A(LDA,N), B(LDB,N)   REAL EPS ! machine constant PARAMETER (EPS = 1.1920929E-07) INTEGER I, J, K, P ! local variables REAL F, TOL   !----------------------------------------------------------------------- ! Begin. !----------------------------------------------------------------------- IF (N < 1) THEN ! Validate. IERR = -1 RETURN ELSE IF (N > LDA .OR. N > LDB) THEN IERR = -2 RETURN END IF IERR = 0   F = 0. ! Frobenius norm of A DO J = 1, N DO I = 1, N F = F + A(I,J)**2 END DO END DO F = SQRT(F) TOL = F * EPS   DO J = 1, N ! Set B to identity matrix. DO I = 1, N IF (I .EQ. J) THEN B(I,J) = 1. ELSE B(I,J) = 0. END IF END DO END DO   ! Main loop DO K = 1, N F = ABS(A(K,K)) ! Find pivot. P = K DO I = K+1, N IF (ABS(A(I,K)) > F) THEN F = ABS(A(I,K)) P = I END IF END DO   IF (F < TOL) THEN ! Matrix is singular. IERR = 1 RETURN END IF   IF (P .NE. K) THEN ! Swap rows. DO J = K, N F = A(K,J) A(K,J) = A(P,J) A(P,J) = F END DO DO J = 1, N F = B(K,J) B(K,J) = B(P,J) B(P,J) = F END DO END IF   F = 1. / A(K,K) ! Scale row so pivot is 1. DO J = K, N A(K,J) = A(K,J) * F END DO DO J = 1, N B(K,J) = B(K,J) * F END DO   DO 10 I = 1, N ! Subtract to get zeros. IF (I .EQ. K) GO TO 10 F = A(I,K) DO J = K, N A(I,J) = A(I,J) - A(K,J) * F END DO DO J = 1, N B(I,J) = B(I,J) - B(K,J) * F END DO 10 CONTINUE END DO   RETURN END ! of gjinv
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Common_Lisp
Common Lisp
  (defun fizzbuzz (limit factor-words) (loop for i from 1 to limit if (assoc-if #'(lambda (factor) (zerop (mod i factor))) factor-words) do (loop for (factor . word) in factor-words when (zerop (mod i factor)) do (princ word) finally (fresh-line)) else do (format t "~a~%" i)))   (defun read-factors (&optional factor-words) (princ "> ") (let ((input (read-line t nil))) (cond ((zerop (length input)) (sort factor-words #'< :key #'car)) ((digit-char-p (char input 0)) (multiple-value-bind (n i) (parse-integer input :junk-allowed t) (read-factors (acons n (string-trim " " (subseq input i)) factor-words)))) (t (write-line "Invalid input.") (read-factors factor-words)))))   (defun main () (loop initially (princ "> ") for input = (read-line t nil) until (and (> (length input) 0) (digit-char-p (char input 0)) (not (zerop (parse-integer input :junk-allowed t)))) finally (fizzbuzz (parse-integer input :junk-allowed t) (read-factors))))  
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Ursa
Ursa
import "math"   def hailstone (int n) decl int<> seq while (> n 1) append n seq if (= (mod n 2) 0) set n (floor (/ n 2)) else set n (int (+ (* 3 n) 1)) end if end while append n seq return seq end hailstone
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Bracmat
Bracmat
a:?seq:?c & whl ' ( chr$(asc$!c+1):~>z:?c & !seq !c:?seq ) & !seq
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Nyquist
Nyquist
(format t "Hello world!")
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Ursala
Ursala
pmgs("x","y") = ("y","x") # the pattern matching way   ugs = ~&rlX # the idiosyncratic Ursala way   #cast %sWL   test = <pmgs ('a','b'),ugs ('x','y')>
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#V
V
[swap [a b : b a] view].   1 2 swap = 2 1 'hello' 'hi' swap
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#FunL
FunL
def powers( m ) = map( (^ m), 0.. )   def filtered( s@sh:_, ch:ct ) | sh > ch = filtered( s, ct ) filtered( sh:st, c@ch:_ ) | sh < ch = sh # filtered( st, c ) filtered( _:st, c ) = filtered( st, c )   println( filtered(powers(2), powers(3)).drop(20).take(10) )
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#TSE_SAL
TSE SAL
    // library: math: get: greatest: common: divisor <description>greatest common divisor whole numbers. Euclid's algorithm. Recursive version</description> <version control></version control> <version>1.0.0.0.3</version> <version control></version control> (filenamemacro=getmacdi.s) [<Program>] [<Research>] [kn, ri, su, 20-01-2013 14:22:41] INTEGER PROC FNMathGetGreatestCommonDivisorI( INTEGER x1I, INTEGER x2I ) // IF ( x2I == 0 ) // RETURN( x1I ) // ENDIF // RETURN( FNMathGetGreatestCommonDivisorI( x2I, x1I MOD x2I ) ) // END   PROC Main() STRING s1[255] = "353" STRING s2[255] = "46" REPEAT IF ( NOT ( Ask( " = ", s1, _EDIT_HISTORY_ ) ) AND ( Length( s1 ) > 0 ) ) RETURN() ENDIF IF ( NOT ( Ask( " = ", s2, _EDIT_HISTORY_ ) ) AND ( Length( s2 ) > 0 ) ) RETURN() ENDIF Warn( FNMathGetGreatestCommonDivisorI( Val( s1 ), Val( s2 ) ) ) // gives e.g. 1 UNTIL FALSE END    
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#TXR
TXR
$ txr -p '(gcd (expt 2 123) (expt 6 49))' 562949953421312
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#J
J
row0=: u: 9812+2}.5|i.10 king=: u:9812 rook=: u:9814 bish=: u:9815 pos=: I.@e. bishok=: 1=2+/ .| pos&bish rookok=: pos&rook -: (<./,>./)@pos&(rook,king) ok=: bishok*rookok perm=: A.&i.~ ! valid=: (#~ ok"1) ~.row0{"1~perm 8 gen=: valid {~ ? bind 960
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Java
Java
import java.util.Arrays; import java.util.Collections; import java.util.List;   public class Chess960{ private static List<Character> pieces = Arrays.asList('R','B','N','Q','K','N','B','R');   public static List<Character> generateFirstRank(){ do{ Collections.shuffle(pieces); }while(!check(pieces.toString().replaceAll("[^\\p{Upper}]", ""))); //List.toString adds some human stuff, remove that   return pieces; }   private static boolean check(String rank){ if(!rank.matches(".*R.*K.*R.*")) return false; //king between rooks if(!rank.matches(".*B(..|....|......|)B.*")) return false; //all possible ways bishops can be placed return true; }   public static void main(String[] args){ for(int i = 0; i < 10; i++){ System.out.println(generateFirstRank()); } } }
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Aime
Aime
integer f0(void); # No arguments void f1(integer, real); # Two arguments real f2(...); # Varargs void f3(integer, ...); # Varargs   void f4(integer &, text &); # Two arguments (integer and string), pass by reference integer f5(integer, integer (*)(integer)); # Two arguments: integer and function returning integer and taking one integer argument integer f6(integer a, real b); # Parameters names are allowed record f7(void); # Function returning an associative array
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#ALGOL_68
ALGOL 68
#!/usr/bin/a68g --script # # -*- coding: utf-8 -*- #   # An explanation of any placement restrictions for prototype declarations # PROC VOID no args; # Declare a function with no argument that returns an INTeger # PROC (INT #a#,INT #b#)VOID two args; # Declare a function with two arguments that returns an INTeger # MODE VARARGS = UNION(INT,REAL,COMPL); PROC ([]VARARGS)VOID var args; # An empty parameter list can be used to declare a function that accepts varargs # PROC (INT, []VARARGS)VOID at least one args; # One mandatory INTeger argument followed by varargs #   MODE OPTINT = UNION(VOID,INT), OPTSTRING=UNION(VOID,STRING); # a function that utilizes optional arguments # PROC (OPTINT, OPTSTRING)VOID optional arguments;   # A prototype declaration for a function that utilizes named parameters # MODE KWNAME = STRUCT(STRING name), KWSPECIES = STRUCT(STRING species), KWBREED = STRUCT(STRING breed), OWNER=STRUCT(STRING first name, middle name, last name);   # due to the "Yoneda ambiguity" simple arguments must have an unique operator defined # OP NAME = (STRING name)KWNAME: (KWNAME opt; name OF opt := name; opt), SPECIES = (STRING species)KWSPECIES: (KWSPECIES opt; species OF opt := species; opt), BREED = (STRING breed)KWBREED: (KWBREED opt; breed OF opt := breed; opt);   PROC ([]UNION(KWNAME,KWSPECIES,KWBREED,OWNER) #options#)VOID print pet;   # subroutines, and fuctions are procedures, so have the same prototype declarations #   # An explanation and example of any special forms of prototyping not covered by the above: # COMMENT If a function has no arguments, eg f, then it is not requied to pass it a "vacuum()" to call it, eg "f()" not correct! Rather is can be called without the () vacuum. eg "f" A GOTO "label" is equivalent to "PROC VOID label". END COMMENT   SKIP
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Clojure
Clojure
(defn first-digit [n] (Integer/parseInt (subs (str n) 0 1)))   (defn last-digit [n] (mod n 10))   (defn bookend-number [n] (+ (* 10 (first-digit n)) (last-digit n)))   (defn is-gapful? [n] (and (>= n 100) (zero? (mod n (bookend-number n)))))   (defn gapful-from [n] (filter is-gapful? (iterate inc n)))   (defn gapful [] (gapful-from 1))   (defn gapfuls-in-range [start size] (take size (gapful-from start)))   (defn report-range [[start size]] (doall (map println [(format "First %d gapful numbers >= %d:" size start) (gapfuls-in-range start size) ""])))   (doall (map report-range [ [1 30] [1000000 15] [1000000000 10] ]))
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#C
C
#include <stdio.h> #include <stdlib.h> #include <math.h>   #define mat_elem(a, y, x, n) (a + ((y) * (n) + (x)))   void swap_row(double *a, double *b, int r1, int r2, int n) { double tmp, *p1, *p2; int i;   if (r1 == r2) return; for (i = 0; i < n; i++) { p1 = mat_elem(a, r1, i, n); p2 = mat_elem(a, r2, i, n); tmp = *p1, *p1 = *p2, *p2 = tmp; } tmp = b[r1], b[r1] = b[r2], b[r2] = tmp; }   void gauss_eliminate(double *a, double *b, double *x, int n) { #define A(y, x) (*mat_elem(a, y, x, n)) int i, j, col, row, max_row,dia; double max, tmp;   for (dia = 0; dia < n; dia++) { max_row = dia, max = A(dia, dia);   for (row = dia + 1; row < n; row++) if ((tmp = fabs(A(row, dia))) > max) max_row = row, max = tmp;   swap_row(a, b, dia, max_row, n);   for (row = dia + 1; row < n; row++) { tmp = A(row, dia) / A(dia, dia); for (col = dia+1; col < n; col++) A(row, col) -= tmp * A(dia, col); A(row, dia) = 0; b[row] -= tmp * b[dia]; } } for (row = n - 1; row >= 0; row--) { tmp = b[row]; for (j = n - 1; j > row; j--) tmp -= x[j] * A(row, j); x[row] = tmp / A(row, row); } #undef A }   int main(void) { double a[] = { 1.00, 0.00, 0.00, 0.00, 0.00, 0.00, 1.00, 0.63, 0.39, 0.25, 0.16, 0.10, 1.00, 1.26, 1.58, 1.98, 2.49, 3.13, 1.00, 1.88, 3.55, 6.70, 12.62, 23.80, 1.00, 2.51, 6.32, 15.88, 39.90, 100.28, 1.00, 3.14, 9.87, 31.01, 97.41, 306.02 }; double b[] = { -0.01, 0.61, 0.91, 0.99, 0.60, 0.02 }; double x[6]; int i;   gauss_eliminate(a, b, x, 6);   for (i = 0; i < 6; i++) printf("%g\n", x[i]);   return 0; }
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#R
R
  place_kings <- function(brd){ ### # Function that puts the two kings on the board # and makes sure that they are not adjacent ### while (TRUE) { # generate positions for white and black kings rank_white <- sample(1:8, 1) ; file_white <- sample(1:8, 1) rank_black <- sample(1:8, 1) ; file_black <- sample(1:8, 1) # compute the differences between ranks and files diff_vec <- c(abs(rank_white - rank_black), abs(file_white - file_black)) # if the two kings are not adjacent, place them on the board if (sum(diff_vec) > 2 | setequal(diff_vec, c(0,2))) { brd[rank_white, file_white] <- "K" brd[rank_black, file_black] <- "k" break } } return(brd) }   pawn_on_extreme_ranks <- function(pc, pr){ ### # Function that checks whether a pawn is on the first or eight rank # (such a situation is not possible in chess) ### if (pc %in% c("P","p") & pr %in% c(1,8)) return(TRUE) else return(FALSE) }   populate_board <- function(brd, wp, bp){ ### # Function that puts pieces on the board making sure that they # are not on the same squares, and verifying for pawn_on_extreme_ranks ### # initialization piece_list <- c("P", "N", "B", "R", "Q") for (color in c("white", "black")){ # iterate for white (first) and black (after) pieces if (color == "white"){ n_pieces = wp pieces = piece_list } else { n_pieces = bp pieces = tolower(piece_list) } # place pieces one by one until we have them while (n_pieces != 0){ piece_rank <- sample(1:8, 1) ; piece_file <- sample(1:8, 1) piece <- sample(pieces, 1) # check if square is empty and it is not a pawn on an extreme rank if (brd[piece_rank, piece_file] == " " & !pawn_on_extreme_ranks(piece, piece_rank)){ brd[piece_rank, piece_file] <- piece n_pieces <- n_pieces - 1 } } } return(brd) }   fen_from_board <- function(brd){ ### # Function that prints out the FEN of a given input board ### # create vector of positions by row fen <- apply(brd, 1, function(x) { r <- rle(x) paste(ifelse(r$values == " ", r$lengths, r$values), collapse = "") }) # paste them together with separator '/' and add the final string fen <- paste(paste(fen, collapse = "/"), "w - - 0 1") return(fen) }   generate_fen <- function(){ ### # This function calls all the functions above and generates # the board representation along with its FEN ### # initialization board <- matrix(" ", nrow = 8, ncol = 8) # generate random amount of white and black pieces (kings excluded) n_pieces_white <- sample(0:31, 1) ; n_pieces_black <- sample(0:31, 1) # place kings on board board <- place_kings(board) # put other pieces on board board <- populate_board(board, wp = n_pieces_white, bp = n_pieces_black) # print board and FEN print(board) cat("\n") cat(fen_from_board(board)) }   generate_fen()  
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#FreeBASIC
FreeBASIC
#include once "matmult.bas" #include once "rowech.bas"   function matinv( A as Matrix ) as Matrix dim ret as Matrix, working as Matrix dim as uinteger i, j if not ubound( A.m, 1 ) = ubound( A.m, 2 ) then return ret dim as integer n = ubound(A.m, 1) redim ret.m( n, n ) working = Matrix( n+1, 2*(n+1) ) for i = 0 to n for j = 0 to n working.m(i, j) = A.m(i, j) next j working.m(i, i+n+1) = 1 next i working = rowech(working) for i = 0 to n for j = 0 to n ret.m(i, j) = working.m(i, j+n+1) next j next i return ret end function   dim as integer i, j dim as Matrix M = Matrix(3,3) for i = 0 to 2 for j = 0 to 2 M.m(i, j) = 1 + i*i + 3*j + (i+j) mod 2 'just some arbitrary values print M.m(i, j), next j print next i print M = matinv(M) for i = 0 to 2 for j = 0 to 2 print M.m(i, j), next j print next i
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Crystal
Crystal
  counter = 0   puts "Enter a maximum number:" limit = gets   puts "Enter the first integer for factoring:" first_int = gets puts "Enter the name of the first integer:" first_int_name = gets   puts "Enter the second integer for factoring:" second_int = gets puts "Enter the name of the second integer:" second_int_name = gets   puts "Enter the third integer for factoring:" third_int = gets puts "Enter the name of the third integer:" third_int_name = gets   if (limit && first_int && second_int && third_int && first_int_name && second_int_name && third_int_name) limit = limit.chomp.to_i first_int = first_int.chomp.to_i second_int = second_int.chomp.to_i third_int = third_int.chomp.to_i while limit > counter counter += 1 if (counter % first_int) == 0 && (counter % second_int) == 0 && (counter % third_int) == 0 puts first_int_name + second_int_name + third_int_name elsif (counter % first_int) == 0 && (counter % second_int) == 0 puts first_int_name + second_int_name elsif (counter % first_int) == 0 puts first_int_name elsif (counter % second_int) == 0 puts second_int_name elsif (counter % third_int) == 0 puts third_int_name else puts counter end end else exit end  
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Ursala
Ursala
#import std #import nat   hail = @iNC ~&h~=1->x ^C\~& @h ~&h?\~&t successor+ sum@iNiCX   #show+   main =   < ^T(@ixX take/$4; %nLP~~lrxPX; ^|TL/~& :/'...',' has length '--@h+ %nP+ length) hail 27, ^|TL(~&,:/' has sequence length ') %nP~~ nleq$^&r ^(~&,length+ hail)* nrange/1 100000>
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Brainf.2A.2A.2A
Brainf***
Make room for 26 characters >>>>>>>>>>>>> >>>>>>>>>>>>> Set counter to 26 >> +++++++++++++ +++++++++++++ Generate the numbers 1 to 26 [-<< Decrement counter [+<] Add one to each nonzero cell moving right to left + Add one to first zero cell encountered [>]> Return head to counter ] << Add 96 to each cell [ ++++++++++++++++ ++++++++++++++++ ++++++++++++++++ ++++++++++++++++ ++++++++++++++++ ++++++++++++++++ <] Print each cell >[.>] ++++++++++. \n
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Oberon-2
Oberon-2
  MODULE Goodbye; IMPORT Out; PROCEDURE World*; BEGIN Out.String("Hello world!");Out.Ln END World; BEGIN World; END Goodbye.  
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#VBScript
VBScript
sub swap( byref x, byref y ) dim temp temp = x x = y y = temp end sub
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Verbexx
Verbexx
// user-defined swap verb -- parms are passed by alias, not value, so they can be updated:   '<==> [_a] @FN [_b] { _a _b = _b _a } by_alias: ;     // test out swap verb   @VAR a = 12345; @VAR b = "*****";   @SAY "a=" a " b=" b;   \b <==> \a; // "\" verb prevents evaluation of a and b here, // so they can be passed by alias to <==> @SAY "a=" a " b=" b;   a b = b a; // swap them back, just using the usual = verb   @SAY "a=" a " b=" b;
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Go
Go
package main   import ( "fmt" "math" )   // note: exponent not limited to ints func newPowGen(e float64) func() float64 { var i float64 return func() (r float64) { r = math.Pow(i, e) i++ return } }   // given two functions af, bf, both monotonically increasing, return a // new function that returns values of af not returned by bf. func newMonoIncA_NotMonoIncB_Gen(af, bf func() float64) func() float64 { a, b := af(), bf() return func() (r float64) { for { if a < b { r = a a = af() break } if b == a { a = af() } b = bf() } return } }   func main() { fGen := newMonoIncA_NotMonoIncB_Gen(newPowGen(2), newPowGen(3)) for i := 0; i < 20; i++ { fGen() } for i := 0; i < 10; i++ { fmt.Print(fGen(), " ") } fmt.Println() }
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#TypeScript
TypeScript
function gcd(a: number, b: number) { a = Math.abs(a); b = Math.abs(b);   if (b > a) { let temp = a; a = b; b = temp; }   while (true) { a %= b; if (a === 0) { return b; } b %= a; if (b === 0) { return a; } } }
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#JavaScript
JavaScript
function ch960startPos() { var rank = new Array(8), // randomizer (our die) d = function(num) { return Math.floor(Math.random() * ++num) }, emptySquares = function() { var arr = []; for (var i = 0; i < 8; i++) if (rank[i] == undefined) arr.push(i); return arr; }; // place one bishop on any black square rank[d(2) * 2] = "♗"; // place the other bishop on any white square rank[d(2) * 2 + 1] = "♗"; // place the queen on any empty square rank[emptySquares()[d(5)]] = "♕"; // place one knight on any empty square rank[emptySquares()[d(4)]] = "♘"; // place the other knight on any empty square rank[emptySquares()[d(3)]] = "♘"; // place the rooks and the king on the squares left, king in the middle for (var x = 1; x <= 3; x++) rank[emptySquares()[0]] = x==2 ? "♔" : "♖"; return rank; }   // testing (10 times) for (var x = 1; x <= 10; x++) console.log(ch960startPos().join(" | "));
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Amazing_Hopper
Amazing Hopper
  #!/usr/bin/hopper   // Archivo Hopper #include <hopper.h>   #context-free noargs /* Declare a pseudo-function with no argument */ #synon noargs no arguments #context multiargs /* Declare a pseudo-function with multi arguments */ #proto twoargs(_X_,_Y_) /* Declare a pseudo-function with two arguments. #PROTO need arguments */   main: no arguments _two args(2,2) // pseudo-function #proto need "_" sufix println {1,2,3,"hola mundo!","\n"}, multiargs exit(0)   .locals   multiargs: _PARAMS_={},pushall(_PARAMS_) [1:3]get(_PARAMS_),stats(SUMMATORY),println {"Mensaje: "}[4:5]get(_PARAMS_),println clear(_PARAMS_) back   twoargs(a,b) {a}mulby(b) back   // This function is as useful a s an ashtray on a motorcycle: no args: {0}minus(0),kill back   {0}return  
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#C
C
int noargs(void); /* Declare a function with no argument that returns an integer */ int twoargs(int a,int b); /* Declare a function with two arguments that returns an integer */ int twoargs(int ,int); /* Parameter names are optional in a prototype definition */ int anyargs(); /* An empty parameter list can be used to declare a function that accepts varargs */ int atleastoneargs(int, ...); /* One mandatory integer argument followed by varargs */
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#C.23
C#
using System; abstract class Printer { public abstract void Print(); }   class PrinterImpl : Printer { public override void Print() { Console.WriteLine("Hello world!"); } }
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#11l
11l
V _a = [ 1.00000000000000000000, 0.57721566490153286061, -0.65587807152025388108, -0.04200263503409523553, 0.16653861138229148950, -0.04219773455554433675, -0.00962197152787697356, 0.00721894324666309954, -0.00116516759185906511, -0.00021524167411495097, 0.00012805028238811619, -0.00002013485478078824, -0.00000125049348214267, 0.00000113302723198170, -0.00000020563384169776, 0.00000000611609510448, 0.00000000500200764447, -0.00000000118127457049, 0.00000000010434267117, 0.00000000000778226344, -0.00000000000369680562, 0.00000000000051003703, -0.00000000000002058326, -0.00000000000000534812, 0.00000000000000122678, -0.00000000000000011813, 0.00000000000000000119, 0.00000000000000000141, -0.00000000000000000023, 0.00000000000000000002 ] F gamma(x) V y = x - 1.0 V sm = :_a.last L(n) (:_a.len-2 .. 0).step(-1) sm = sm * y + :_a[n] R 1.0 / sm   L(i) 1..10 print(‘#.14’.format(gamma(i / 3.0)))
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#COBOL
COBOL
IDENTIFICATION DIVISION. PROGRAM-ID. GAPFUL.   DATA DIVISION. WORKING-STORAGE SECTION. 01 COMPUTATION. 02 N PIC 9(10). 02 N-DIGITS REDEFINES N. 03 ND PIC 9 OCCURS 10 TIMES. 02 DIV-CHECK PIC 9(10)V9(2). 02 DIV-PARTS REDEFINES DIV-CHECK. 03 DIV-INT PIC 9(10). 03 DIV-FRAC PIC 9(2). 02 GAP-AMOUNT PIC 99. 02 GAP-DSOR PIC 99. 02 FIRST-DIGIT PIC 99. 01 OUTPUT-FORMAT. 02 N-OUT PIC Z(10).   PROCEDURE DIVISION. BEGIN. DISPLAY "First 30 gapful numbers >= 100:". MOVE 100 TO N. MOVE 30 TO GAP-AMOUNT. PERFORM CHECK-GAPFUL-NUMBER.   DISPLAY " ". DISPLAY "First 15 gapful numbers >= 1000000:". MOVE 1000000 TO N. MOVE 15 TO GAP-AMOUNT. PERFORM CHECK-GAPFUL-NUMBER.   DISPLAY " ". DISPLAY "First 10 gapful numbers >= 1000000000:". MOVE 1000000000 TO N. MOVE 10 TO GAP-AMOUNT. PERFORM CHECK-GAPFUL-NUMBER. STOP RUN.   CHECK-GAPFUL-NUMBER. SET FIRST-DIGIT TO 1. INSPECT N TALLYING FIRST-DIGIT FOR LEADING '0'. COMPUTE GAP-DSOR = ND(FIRST-DIGIT) * 10 + ND(10). DIVIDE N BY GAP-DSOR GIVING DIV-CHECK. IF DIV-FRAC IS EQUAL TO 0 MOVE N TO N-OUT DISPLAY N-OUT SUBTRACT 1 FROM GAP-AMOUNT. ADD 1 TO N. IF GAP-AMOUNT IS GREATER THAN 0 GO TO CHECK-GAPFUL-NUMBER.
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#C.23
C#
  using System;   namespace Rosetta { internal class Vector { private double[] b; internal readonly int rows;   internal Vector(int rows) { this.rows = rows; b = new double[rows]; }   internal Vector(double[] initArray) { b = (double[])initArray.Clone(); rows = b.Length; }   internal Vector Clone() { Vector v = new Vector(b); return v; }   internal double this[int row] { get { return b[row]; } set { b[row] = value; } }   internal void SwapRows(int r1, int r2) { if (r1 == r2) return; double tmp = b[r1]; b[r1] = b[r2]; b[r2] = tmp; }   internal double norm(double[] weights) { double sum = 0; for (int i = 0; i < rows; i++) { double d = b[i] * weights[i]; sum += d*d; } return Math.Sqrt(sum); }   internal void print() { for (int i = 0; i < rows; i++) Console.WriteLine(b[i]); Console.WriteLine(); }   public static Vector operator-(Vector lhs, Vector rhs) { Vector v = new Vector(lhs.rows); for (int i = 0; i < lhs.rows; i++) v[i] = lhs[i] - rhs[i]; return v; } }   class Matrix { private double[] b; internal readonly int rows, cols;   internal Matrix(int rows, int cols) { this.rows = rows; this.cols = cols; b = new double[rows * cols]; }   internal Matrix(int size) { this.rows = size; this.cols = size; b = new double[rows * cols]; for (int i = 0; i < size; i++) this[i, i] = 1; }   internal Matrix(int rows, int cols, double[] initArray) { this.rows = rows; this.cols = cols; b = (double[])initArray.Clone(); if (b.Length != rows * cols) throw new Exception("bad init array"); }   internal double this[int row, int col] { get { return b[row * cols + col]; } set { b[row * cols + col] = value; } }   public static Vector operator*(Matrix lhs, Vector rhs) { if (lhs.cols != rhs.rows) throw new Exception("I can't multiply matrix by vector"); Vector v = new Vector(lhs.rows); for (int i = 0; i < lhs.rows; i++) { double sum = 0; for (int j = 0; j < rhs.rows; j++) sum += lhs[i,j]*rhs[j]; v[i] = sum; } return v; }   internal void SwapRows(int r1, int r2) { if (r1 == r2) return; int firstR1 = r1 * cols; int firstR2 = r2 * cols; for (int i = 0; i < cols; i++) { double tmp = b[firstR1 + i]; b[firstR1 + i] = b[firstR2 + i]; b[firstR2 + i] = tmp; } }   //with partial pivot internal void ElimPartial(Vector B) { for (int diag = 0; diag < rows; diag++) { int max_row = diag; double max_val = Math.Abs(this[diag, diag]); double d; for (int row = diag + 1; row < rows; row++) if ((d = Math.Abs(this[row, diag])) > max_val) { max_row = row; max_val = d; } SwapRows(diag, max_row); B.SwapRows(diag, max_row); double invd = 1 / this[diag, diag]; for (int col = diag; col < cols; col++) this[diag, col] *= invd; B[diag] *= invd; for (int row = 0; row < rows; row++) { d = this[row, diag]; if (row != diag) { for (int col = diag; col < cols; col++) this[row, col] -= d * this[diag, col]; B[row] -= d * B[diag]; } } } }   internal void print() { for (int i = 0; i < rows; i++) { for (int j = 0; j < cols; j++) Console.Write(this[i,j].ToString()+" "); Console.WriteLine(); } } } }  
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Raku
Raku
sub pick-FEN { # First we chose how many pieces to place my $n = (2..32).pick;   # Then we pick $n squares my @n = (^64).pick($n);   # We try to find suitable king positions on non-adjacent squares. # If we could not find any, we return recursively return pick-FEN() unless my @kings[2] = first -> [$a, $b] { $a !== $b && abs($a div 8 - $b div 8) | abs($a mod 8 - $b mod 8) > 1 }, (@n X @n);   # We make a list of pieces we can pick (apart from the kings) my @pieces = <p P n N b B r R q Q>;   # We make a list of two king symbols to pick randomly a black or white king my @k = <K k>.pick(*);   return (gather for ^64 -> $sq { if $sq == @kings.any { take @k.shift } elsif $sq == @n.any { my $row = 7 - $sq div 8; take $row == 7 ?? @pieces.grep(none('P')).pick !! $row == 0 ?? @pieces.grep(none('p')).pick !! @pieces.pick; } else { take 'ø' } }).rotor(8)».join».subst(/ø+/,{ .chars }, :g).join('/') ~ ' w - - 0 1'; }   say pick-FEN();
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Generic
Generic
  // The Generic Language is a database compiler. This code is compiled into database then executed out of database.   generic coordinaat { ecs; uuii;   coordinaat() { ecs=+a;uuii=+a;}   coordinaat(ecs_set,uuii_set) { ecs = ecs_set; uuii=uuii_set;}   operaator<(c) { iph ecs < c.ecs return troo; iph c.ecs < ecs return phals; iph uuii < c.uuii return troo; return phals; }   operaator==(connpair) // eecuuols and not eecuuols deriiu phronn operaator< { iph this < connpair return phals; iph connpair < this return phals; return troo; }   operaator!=(connpair) { iph this < connpair return troo; iph connpair < this return troo; return phals; }   too_string() { return "(" + ecs.too_string() + "," + uuii.too_string() + ")"; }   print() { str = too_string(); str.print(); }   println() { str = too_string(); str.println(); } }   generic nnaatrics { s; // this is a set of coordinaat/ualioo pairs. iteraator; // this field holds an iteraator phor the nnaatrics.   nnaatrics() // no parameters required phor nnaatrics construction. { s = nioo set(); // create a nioo set of coordinaat/ualioo pairs. iteraator = nul; // the iteraator is initially set to nul. }   nnaatrics(copee) // copee the nnaatrics. { s = nioo set(); // create a nioo set of coordinaat/ualioo pairs. iteraator = nul; // the iteraator is initially set to nul.   r = copee.rouus; c = copee.cols; i = 0; uuiil i < r { j = 0; uuiil j < c { this[i,j] = copee[i,j]; j++; } i++; } }   begin { get { return s.begin; } } // property: used to commence manual iteraashon.   end { get { return s.end; } } // property: used to dephiin the end itenn of iteraashon   operaator<(a) // les than operaator is corld bii the avl tree algorithnns { // this operaator innpliis phor instance that you could potenshalee hav sets ou nnaatricss. iph cees < a.cees // connpair the cee sets phurst. return troo; els iph a.cees < cees return phals; els // the cee sets are eecuuol thairphor connpair nnaatrics elennents. { phurst1 = begin; lahst1 = end; phurst2 = a.begin; lahst2 = a.end;   uuiil phurst1 != lahst1 && phurst2 != lahst2 { iph phurst1.daata.ualioo < phurst2.daata.ualioo return troo; els { iph phurst2.daata.ualioo < phurst1.daata.ualioo return phals; els { phurst1 = phurst1.necst; phurst2 = phurst2.necst; } } }   return phals; } }   operaator==(connpair) // eecuuols and not eecuuols deriiu phronn operaator< { iph this < connpair return phals; iph connpair < this return phals; return troo; }   operaator!=(connpair) { iph this < connpair return troo; iph connpair < this return troo; return phals; }     operaator[](cee_a,cee_b) // this is the nnaatrics indexer. { set { trii { s >> nioo cee_ualioo(new coordinaat(cee_a,cee_b)); } catch {} s << nioo cee_ualioo(new coordinaat(nioo integer(cee_a),nioo integer(cee_b)),ualioo); } get { d = s.get(nioo cee_ualioo(new coordinaat(cee_a,cee_b))); return d.ualioo; } }   operaator>>(coordinaat) // this operaator reennoous an elennent phronn the nnaatrics. { s >> nioo cee_ualioo(coordinaat); return this; }   iteraat() // and this is how to iterate on the nnaatrics. { iph iteraator.nul() { iteraator = s.lepht_nnohst; iph iteraator == s.heder return nioo iteraator(phals,nioo nun()); els return nioo iteraator(troo,iteraator.daata.ualioo); } els { iteraator = iteraator.necst;   iph iteraator == s.heder { iteraator = nul; return nioo iteraator(phals,nioo nun()); } els return nioo iteraator(troo,iteraator.daata.ualioo); } }   couunt // this property returns a couunt ou elennents in the nnaatrics. { get { return s.couunt; } }   ennptee // is the nnaatrics ennptee? { get { return s.ennptee; } }     lahst // returns the ualioo of the lahst elennent in the nnaatrics. { get { iph ennptee throuu "ennptee nnaatrics"; els return s.lahst.ualioo; } }   too_string() // conuerts the nnaatrics too aa string { return s.too_string(); }   print() // prints the nnaatrics to the consohl. { out = too_string(); out.print(); }   println() // prints the nnaatrics as a liin too the consohl. { out = too_string(); out.println(); }   cees // return the set ou cees ou the nnaatrics (a set of coordinaats). { get { k = nioo set(); phor e : s k << e.cee; return k; } }   operaator+(p) { ouut = nioo nnaatrics(); phurst1 = begin; lahst1 = end; phurst2 = p.begin; lahst2 = p.end; uuiil phurst1 != lahst1 && phurst2 != lahst2 { ouut[phurst1.daata.cee.ecs,phurst1.daata.cee.uuii] = phurst1.daata.ualioo + phurst2.daata.ualioo; phurst1 = phurst1.necst; phurst2 = phurst2.necst; } return ouut; }   operaator-(p) { ouut = nioo nnaatrics(); phurst1 = begin; lahst1 = end; phurst2 = p.begin; lahst2 = p.end; uuiil phurst1 != lahst1 && phurst2 != lahst2 { ouut[phurst1.daata.cee.ecs,phurst1.daata.cee.uuii] = phurst1.daata.ualioo - phurst2.daata.ualioo; phurst1 = phurst1.necst; phurst2 = phurst2.necst; } return ouut; }   rouus { get { r = +a; phurst1 = begin; lahst1 = end; uuiil phurst1 != lahst1 { iph r < phurst1.daata.cee.ecs r = phurst1.daata.cee.ecs; phurst1 = phurst1.necst; } return r + +b; } }   cols { get { c = +a; phurst1 = begin; lahst1 = end; uuiil phurst1 != lahst1 { iph c < phurst1.daata.cee.uuii c = phurst1.daata.cee.uuii; phurst1 = phurst1.necst; } return c + +b; } }   operaator*(o) { iph cols != o.rouus throw "rouus-cols nnisnnatch"; reesult = nioo nnaatrics(); rouu_couunt = rouus; colunn_couunt = o.cols; loop = cols; i = +a; uuiil i < rouu_couunt { g = +a; uuiil g < colunn_couunt { sunn = +a.a; h = +a; uuiil h < loop { a = this[i, h];   b = o[h, g]; nn = a * b; sunn = sunn + nn; h++; }   reesult[i, g] = sunn;   g++; } i++; } return reesult; }   suuop_rouus(a, b) { c = cols; i = 0; uuiil u < cols { suuop = this[a, i]; this[a, i] = this[b, i]; this[b, i] = suuop; i++; } }   suuop_colunns(a, b) { r = rouus; i = 0; uuiil i < rouus { suuopp = this[i, a]; this[i, a] = this[i, b]; this[i, b] = suuop; i++; } }   transpohs { get { reesult = new nnaatrics();   r = rouus; c = cols; i=0; uuiil i < r { g = 0; uuiil g < c { reesult[g, i] = this[i, g]; g++; } i++; }   return reesult; } }   deternninant { get { rouu_couunt = rouus; colunn_count = cols;   if rouu_couunt != colunn_count throw "not a scuuair nnaatrics";   if rouu_couunt == 0 throw "the nnaatrics is ennptee";   if rouu_couunt == 1 return this[0, 0];   if rouu_couunt == 2 return this[0, 0] * this[1, 1] - this[0, 1] * this[1, 0];   temp = nioo nnaatrics();   det = 0.0; parity = 1.0;   j = 0; uuiil j < rouu_couunt { k = 0; uuiil k < rouu_couunt-1 { skip_col = phals;   l = 0; uuiil l < rouu_couunt-1 { if l == j skip_col = troo;   if skip_col n = l + 1; els n = l;   temp[k, l] = this[k + 1, n]; l++; } k++; }   det = det + parity * this[0, j] * temp.deeternninant;   parity = 0.0 - parity; j++; }   return det; } }   ad_rouu(a, b) { c = cols; i = 0; uuiil i < c { this[a, i] = this[a, i] + this[b, i]; i++; } }   ad_colunn(a, b) { c = rouus; i = 0; uuiil i < c { this[i, a] = this[i, a] + this[i, b]; i++; } }   subtract_rouu(a, b) { c = cols; i = 0; uuiil i < c { this[a, i] = this[a, i] - this[b, i]; i++; } }   subtract_colunn(a, b) { c = rouus; i = 0; uuiil i < c { this[i, a] = this[i, a] - this[i, b]; i++; } }   nnultiplii_rouu(rouu, scalar) { c = cols; i = 0; uuiil i < c { this[rouu, i] = this[rouu, i] * scalar; i++; } }   nnultiplii_colunn(colunn, scalar) { r = rouus; i = 0; uuiil i < r { this[i, colunn] = this[i, colunn] * scalar; i++; } }   diuiid_rouu(rouu, scalar) { c = cols; i = 0; uuiil i < c { this[rouu, i] = this[rouu, i] / scalar; i++; } }   diuiid_colunn(colunn, scalar) { r = rouus; i = 0; uuiil i < r { this[i, colunn] = this[i, colunn] / scalar; i++; } }   connbiin_rouus_ad(a,b,phactor) { c = cols; i = 0; uuiil i < c { this[a, i] = this[a, i] + phactor * this[b, i]; i++; } }   connbiin_rouus_subtract(a,b,phactor) { c = cols; i = 0; uuiil i < c { this[a, i] = this[a, i] - phactor * this[b, i]; i++; } }   connbiin_colunns_ad(a,b,phactor) { r = rouus; i = 0; uuiil i < r { this[i, a] = this[i, a] + phactor * this[i, b]; i++; } }   connbiin_colunns_subtract(a,b,phactor) { r = rouus; i = 0; uuiil i < r { this[i, a] = this[i, a] - phactor * this[i, b]; i++; } }   inuers { get { rouu_couunt = rouus; colunn_couunt = cols;   iph rouu_couunt != colunn_couunt throw "nnatrics not scuuair";   els iph rouu_couunt == 0 throw "ennptee nnatrics";   els iph rouu_couunt == 1 { r = nioo nnaatrics(); r[0, 0] = 1.0 / this[0, 0]; return r; }   gauss = nioo nnaatrics(this);   i = 0; uuiil i < rouu_couunt { j = 0; uuiil j < rouu_couunt { iph i == j   gauss[i, j + rouu_couunt] = 1.0; els gauss[i, j + rouu_couunt] = 0.0; j++; }   i++; }   j = 0; uuiil j < rouu_couunt { iph gauss[j, j] == 0.0 { k = j + 1;   uuiil k < rouu_couunt { if gauss[k, j] != 0.0 {gauss.nnaat.suuop_rouus(j, k); break; } k++; }   if k == rouu_couunt throw "nnatrics is singioolar"; }   phactor = gauss[j, j]; iph phactor != 1.0 gauss.diuiid_rouu(j, phactor);   i = j+1; uuiil i < rouu_couunt { gauss.connbiin_rouus_subtract(i, j, gauss[i, j]); i++; }   j++; }   i = rouu_couunt - 1; uuiil i > 0 { k = i - 1; uuiil k >= 0 { gauss.connbiin_rouus_subtract(k, i, gauss[k, i]); k--; } i--; }   reesult = nioo nnaatrics();   i = 0; uuiil i < rouu_couunt { j = 0; uuiil j < rouu_couunt { reesult[i, j] = gauss[i, j + rouu_couunt]; j++; } i++; }   return reesult; } }   }  
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#D
D
import core.stdc.stdlib; import std.stdio;   void main() { int limit; write("Max number (>0): "); readf!"%d\n"(limit); if (limit <= 0) { writeln("The max number to consider must be greater than zero."); exit(1); }   int terms; write("Terms (>0): "); readf!"%d\n"(terms); if (terms <= 0) { writeln("The number of terms to consider must be greater than zero."); exit(1); }   int[] factors = new int[terms]; string[] words = new string[terms];   for (int i=0; i<terms; ++i) { write("Factor ", i+1, " and word: "); readf!"%d %s\n"(factors[i], words[i]); if (factors[i] <= 0) { writeln("The factor to consider must be greater than zero."); exit(1); } }   foreach(n; 1..limit+1) { bool print = true;   for (int i=0; i<terms; ++i) { if (n % factors[i] == 0) { write(words[i]); print = false; } }   if (print) { writeln(n); } else { writeln(); } } }
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#VBA
VBA
Private Function hailstone(ByVal n As Long) As Collection Dim s As New Collection s.Add CStr(n), CStr(n) i = 0 Do While n <> 1 If n Mod 2 = 0 Then n = n / 2 Else n = 3 * n + 1 End If s.Add CStr(n), CStr(n) Loop Set hailstone = s End Function   Private Function hailstone_count(ByVal n As Long) Dim count As Long: count = 1 Do While n <> 1 If n Mod 2 = 0 Then n = n / 2 Else n = 3 * n + 1 End If count = count + 1 Loop hailstone_count = count End Function   Public Sub rosetta() Dim s As Collection, i As Long Set s = hailstone(27) Dim ls As Integer: ls = s.count Debug.Print "hailstone(27) = "; For i = 1 To 4 Debug.Print s(i); ", "; Next i Debug.Print "... "; For i = s.count - 4 To s.count - 1 Debug.Print s(i); ", "; Next i Debug.Print s(s.count) Debug.Print "length ="; ls Dim hmax As Long: hmax = 1 Dim imax As Long: imax = 1 Dim count As Integer For i = 2 To 100000# - 1 count = hailstone_count(i) If count > hmax Then hmax = count imax = i End If Next i Debug.Print "The longest hailstone sequence under 100,000 is"; imax; "with"; hmax; "elements." End Sub
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Burlesque
Burlesque
blsq ) @azr\sh abcdefghijklmnopqrstuvwxyz
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#C
C
#include <stdlib.h>   #define N 26   int main() { unsigned char lower[N];   for (size_t i = 0; i < N; i++) { lower[i] = i + 'a'; }   return EXIT_SUCCESS; }  
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Objeck
Objeck
  class Hello { function : Main(args : String[]) ~ Nil { "Hello world!"->PrintLine(); } }
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Visual_Basic
Visual Basic
Sub Swap(Of T)(ByRef a As T, ByRef b As T) Dim temp = a a = b b = temp End Sub
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Haskell
Haskell
import Data.List.Ordered   powers :: Int -> [Int] powers m = map (^ m) [0..]   squares :: [Int] squares = powers 2   cubes :: [Int] cubes = powers 3   foo :: [Int] foo = filter (not . has cubes) squares   main :: IO () main = print $ take 10 $ drop 20 foo
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#uBasic.2F4tH
uBasic/4tH
Print "GCD of 18 : 12 = "; FUNC(_GCD_Iterative_Euclid(18,12)) Print "GCD of 1071 : 1029 = "; FUNC(_GCD_Iterative_Euclid(1071,1029)) Print "GCD of 3528 : 3780 = "; FUNC(_GCD_Iterative_Euclid(3528,3780))   End   _GCD_Iterative_Euclid Param(2) Local (1) Do While b@ c@ = a@ a@ = b@ b@ = c@ % b@ Loop Return (Abs(a@))
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#UNIX_Shell
UNIX Shell
gcd() { # Calculate $1 % $2 until $2 becomes zero. until test 0 -eq "$2"; do # Parallel assignment: set -- 1 2 set -- "$2" "`expr "$1" % "$2"`" done   # Echo absolute value of $1. test 0 -gt "$1" && set -- "`expr 0 - "$1"`" echo "$1" }   gcd -47376 87843 # => 987
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Julia
Julia
function generateposition() # Placeholder knights rank = ['♘', '♘', '♘', '♘', '♘', '♘', '♘', '♘'] lrank = length(rank)   # Check if a space is available isfree(x::Int) = rank[x] == '♘'   # Place the King rank[indking = rand(2:lrank-1)] = '♔'   # Place rooks rank[indrook = rand(filter(isfree, 1:lrank))] = '♖' if indrook > indking rank[rand(filter(isfree, 1:indking-1))] = '♖' else rank[rand(filter(isfree, indking+1:lrank))] = '♖' end   # Place bishops rank[indbish = rand(filter(isfree, 1:8))] = '♗' pbish = filter(iseven(indbish) ? isodd : iseven, 1:lrank) rank[rand(filter(isfree, pbish))] = '♗'   # Place queen rank[rand(filter(isfree, 1:lrank))] = '♕' return rank end   @show generateposition()
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Kotlin
Kotlin
object Chess960 : Iterable<String> { override fun iterator() = patterns.iterator()   private operator fun invoke(b: String, e: String) { if (e.length <= 1) { val s = b + e if (s.is_valid()) patterns += s } else { for (i in 0 until e.length) { invoke(b + e[i], e.substring(0, i) + e.substring(i + 1)) } } }   private fun String.is_valid(): Boolean { val k = indexOf('K') return indexOf('R') < k && k < lastIndexOf('R') && indexOf('B') % 2 != lastIndexOf('B') % 2 }   private val patterns = sortedSetOf<String>()   init { invoke("", "KQRRNNBB") } }   fun main(args: Array<String>) { Chess960.forEachIndexed { i, s -> println("$i: $s") } }
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#C.2B.2B
C++
int noargs(); // Declare a function with no arguments that returns an integer int twoargs(int a,int b); // Declare a function with two arguments that returns an integer int twoargs(int ,int); // Parameter names are optional in a prototype definition int anyargs(...); // An ellipsis is used to declare a function that accepts varargs int atleastoneargs(int, ...); // One mandatory integer argument followed by varargs template<typename T> T declval(T); //A function template template<typename ...T> tuple<T...> make_tuple(T...); //Function template using parameter pack (since c++11)  
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Clojure
Clojure
(declare foo)
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#360_Assembly
360 Assembly
GAMMAT CSECT USING GAMMAT,R13 SAVEAR B STM-SAVEAR(R15) DC 17F'0' DC CL8'GAMMAT' STM STM R14,R12,12(R13) ST R13,4(R15) ST R15,8(R13) LR R13,R15 * ---- CODE LE F4,=E'0' LH R2,NI LOOPI EQU * AE F4,=E'1' xi=xi+1 LER F0,F4 DE F0,=E'10' x=xi/10 STE F0,X LE F6,X SE F6,=E'1' xx=x-1.0 LH R4,NT BCTR R4,0 SLA R4,2 LE F0,T(R4) STE F0,SUM sum=t(nt) LH R3,NT BCTR R3,0 SH R4,=H'4' LOOPJ CH R3,=H'1' for j=nt-1 downto 1 BL ENDLOOPJ LE F0,SUM MER F0,F6 sum*xx LE F2,T(R4) t(j) AER F0,F2 STE F0,SUM sum=sum*xx+t(j) BCTR R3,0 SH R4,=H'4' B LOOPJ ENDLOOPJ EQU * LE F0,=E'1' DE F0,SUM STE F0,GAMMA gamma=1/sum LE F0,X BAL R14,CONVERT MVC BUF(8),CONVERTM LE F0,GAMMA BAL R14,CONVERT MVC BUF+9(13),CONVERTM WTO MF=(E,WTOMSG) BCT R2,LOOPI * ---- END CODE CNOP 0,4 L R13,4(0,R13) LM R14,R12,12(R13) XR R15,R15 BR R14 * ---- DATA NI DC H'30' NT DC AL2((TEND-T)/4) T DC E'1.00000000000000000000' DC E'0.57721566490153286061' DC E'-0.65587807152025388108' DC E'-0.04200263503409523553' DC E'0.16653861138229148950' DC E'-0.04219773455554433675' DC E'-0.00962197152787697356' DC E'0.00721894324666309954' DC E'-0.00116516759185906511' DC E'-0.00021524167411495097' DC E'0.00012805028238811619' DC E'-0.00002013485478078824' DC E'-0.00000125049348214267' DC E'0.00000113302723198170' DC E'-0.00000020563384169776' DC E'0.00000000611609510448' DC E'0.00000000500200764447' DC E'-0.00000000118127457049' DC E'0.00000000010434267117' DC E'0.00000000000778226344' DC E'-0.00000000000369680562' DC E'0.00000000000051003703' DC E'-0.00000000000002058326' DC E'-0.00000000000000534812' DC E'0.00000000000000122678' DC E'-0.00000000000000011813' DC E'0.00000000000000000119' DC E'0.00000000000000000141' DC E'-0.00000000000000000023' DC E'0.00000000000000000002' TEND DS 0E X DS E SUM DS E GAMMA DS E WTOMSG DS 0F DC AL2(L'BUF),XL2'0000' BUF DC CL80' ' * Subroutine Convertion Float->Display CONVERT CNOP 0,4 ME F0,CONVERTC STE F0,CONVERTF MVI CONVERTS,X'00' L R9,CONVERTF CH R9,=H'0' BZ CONVERT7 BNL CONVERT1 is negative? MVI CONVERTS,X'80' N R9,=X'7FFFFFFF' sign bit CONVERT1 LR R8,R9 N R8,=X'00FFFFFF' BNZ CONVERT2 SR R9,R9 B CONVERT7 CONVERT2 LR R8,R9 N R8,=X'FF000000' characteristic SRL R8,24 CH R8,=H'64' BH CONVERT3 SR R9,R9 B CONVERT7 CONVERT3 CH R8,=H'72' 2**32 BNH CONVERT4 L R9,=X'7FFFFFFF' biggest B CONVERT6 CONVERT4 SR R8,R8 SLDL R8,8 CH R8,=H'72' BL CONVERT5 CH R9,=H'0' BP CONVERT5 L R9,=X'7FFFFFFF' B CONVERT6 CONVERT5 SH R8,=H'72' LCR R8,R8 SLL R8,2 SRL R9,0(R8) CONVERT6 SR R8,R8 IC R8,CONVERTS CH R8,=H'0' sign bit set? BZ CONVERT7 LCR R9,R9 CONVERT7 ST R9,CONVERTB CVD R9,CONVERTP MVC CONVERTD,=X'402020202120202020202020' ED CONVERTD,CONVERTP+2 MVC CONVERTM(6),CONVERTD MVI CONVERTM+6,C'.' MVC CONVERTM+7(6),CONVERTD+6 BR R14 * CONVERTC DC E'1E6' X'45F42400' CONVERTF DS F CONVERTB DS F CONVERTS DS X CONVERTM DS CL13 CONVERTD DS CL12 CONVERTP DS PL8 * EQUREGS EQUREGS REGS=FPR END GAMMAT
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#AutoHotkey
AutoHotkey
AutoTrim Off ; User settings bottompegs := 6 SleepTime := 200 fallspace := 30   ; create the board out := (pad2 := Space(bottompegs*2+1)) "`n" Loop % bottompegs { out .= Space(bottompegs-A_Index+1) Loop % A_Index out .= "* " out .= Space(bottompegs-A_Index+1) . "`n" } StringTrimRight, strboard, out, 1 ; remove last newline Loop % fallspace-1 strboard .= "`n" . pad2 strboard .= "`n" Loop % bottompegs*2+1 strboard .= "="   ; Create Gui Gui Font, , Consolas Gui -Caption Gui Margin, 0, 0 Gui, Add, edit, -VScroll vE, % strboard Gui Show Loop { ballX := bottompegs+1, BallY := 1 strboard := ChangeChar(strboard, BallX, ballY, "O") GuiControl,, E, % strboard sleep SleepTime ; Make ball fall and bounce Loop % bottompegs { strboard := ChangeChar(strboard, BallX, BallY, " ") ballY += 1 ballX += RandAdd() ; MsgBox % ballX ", " ballY GuiControl,, E, % strboard := ChangeChar(strboard, ballX, ballY, "O") sleep SleepTime } ; now fall to the bottom While GetChar(strboard, BallX, BallY+1) = A_Space { strboard := ChangeChar(strboard, BallX, BallY, " ") BallY += 1 strboard := ChangeChar(strboard, BallX, BallY, "O") GuiControl,, E, % strboard sleep SleepTime } } ~Esc:: GuiClose: ExitApp   Space(n){ If n return " " Space(n-1) return "" } RandAdd(){ Random, n, 3, 4 return (n=3 ? -1 : 1) }   GetChar(s, x, y){ Loop Parse, s, `n if (A_Index = y) return SubStr(A_LoopField, x, 1) } ChangeChar(s, x, y, c){ Loop Parse, s, `n { If (A_Index = y) { Loop Parse, A_LoopField If (A_Index = x) out .= c else out .= A_LoopField } else out .= A_LoopField out .= "`n" } StringTrimRight, out, out, 1 ; removes the last newline return out }
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Commodore_BASIC
Commodore BASIC
100 DEF FNFD(N) = VAL(MID$(STR$(N),2,1)) 110 DEF FNLD(N) = N - 10 * INT(N/10) 120 DEF FNBE(N) = 10 * FNFD(N) + FNLD(N) 130 DEF FNGF(N) = (N >= 100) AND (N - FNBE(N)*INT(N/FNBE(N)) = 0) 140 READ S:IF S<0 THEN 260 150 READ C 160 PRINT"THE FIRST"C"GAPFUL NUMBERS >="S":" 170 I=S:F=0 180 IF NOT FNGF(I) THEN 220 190 PRINT I, 200 F=F+1 210 IF F>=C THEN 240 220 I=I+1 230 GOTO 180 240 PRINT:PRINT 250 GOTO 140 260 END 270 DATA 1,30, 1000000,15, 100000000,10 280 DATA -1
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#C.2B.2B
C++
#include <algorithm> #include <cassert> #include <cmath> #include <iomanip> #include <iostream> #include <vector>   template <typename scalar_type> class matrix { public: matrix(size_t rows, size_t columns) : rows_(rows), columns_(columns), elements_(rows * columns) {}   matrix(size_t rows, size_t columns, const std::initializer_list<std::initializer_list<scalar_type>>& values) : rows_(rows), columns_(columns), elements_(rows * columns) { assert(values.size() <= rows_); auto i = elements_.begin(); for (const auto& row : values) { assert(row.size() <= columns_); std::copy(begin(row), end(row), i); i += columns_; } }   size_t rows() const { return rows_; } size_t columns() const { return columns_; }   const scalar_type& operator()(size_t row, size_t column) const { assert(row < rows_); assert(column < columns_); return elements_[row * columns_ + column]; } scalar_type& operator()(size_t row, size_t column) { assert(row < rows_); assert(column < columns_); return elements_[row * columns_ + column]; } private: size_t rows_; size_t columns_; std::vector<scalar_type> elements_; };   template <typename scalar_type> void swap_rows(matrix<scalar_type>& m, size_t i, size_t j) { size_t columns = m.columns(); for (size_t k = 0; k < columns; ++k) std::swap(m(i, k), m(j, k)); }   template <typename scalar_type> std::vector<scalar_type> gauss_partial(const matrix<scalar_type>& a0, const std::vector<scalar_type>& b0) { size_t n = a0.rows(); assert(a0.columns() == n); assert(b0.size() == n); // make augmented matrix matrix<scalar_type> a(n, n + 1); for (size_t i = 0; i < n; ++i) { for (size_t j = 0; j < n; ++j) a(i, j) = a0(i, j); a(i, n) = b0[i]; } // WP algorithm from Gaussian elimination page // produces row echelon form for (size_t k = 0; k < n; ++k) { // Find pivot for column k size_t max_index = k; scalar_type max_value = 0; for (size_t i = k; i < n; ++i) { // compute scale factor = max abs in row scalar_type scale_factor = 0; for (size_t j = k; j < n; ++j) scale_factor = std::max(std::abs(a(i, j)), scale_factor); if (scale_factor == 0) continue; // scale the abs used to pick the pivot scalar_type abs = std::abs(a(i, k))/scale_factor; if (abs > max_value) { max_index = i; max_value = abs; } } if (a(max_index, k) == 0) throw std::runtime_error("matrix is singular"); if (k != max_index) swap_rows(a, k, max_index); for (size_t i = k + 1; i < n; ++i) { scalar_type f = a(i, k)/a(k, k); for (size_t j = k + 1; j <= n; ++j) a(i, j) -= a(k, j) * f; a(i, k) = 0; } } // now back substitute to get result std::vector<scalar_type> x(n); for (size_t i = n; i-- > 0; ) { x[i] = a(i, n); for (size_t j = i + 1; j < n; ++j) x[i] -= a(i, j) * x[j]; x[i] /= a(i, i); } return x; }   int main() { matrix<double> a(6, 6, { {1.00, 0.00, 0.00, 0.00, 0.00, 0.00}, {1.00, 0.63, 0.39, 0.25, 0.16, 0.10}, {1.00, 1.26, 1.58, 1.98, 2.49, 3.13}, {1.00, 1.88, 3.55, 6.70, 12.62, 23.80}, {1.00, 2.51, 6.32, 15.88, 39.90, 100.28}, {1.00, 3.14, 9.87, 31.01, 97.41, 306.02} }); std::vector<double> b{-0.01, 0.61, 0.91, 0.99, 0.60, 0.02}; std::vector<double> x{-0.01, 1.602790394502114, -1.6132030599055613, 1.2454941213714368, -0.4909897195846576, 0.065760696175232}; std::vector<double> y(gauss_partial(a, b)); std::cout << std::setprecision(16); const double epsilon = 1e-14; for (size_t i = 0; i < y.size(); ++i) { assert(std::abs(x[i] - y[i]) <= epsilon); std::cout << y[i] << '\n'; } return 0; }
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#REXX
REXX
/*REXX program generates a chess position (random pieces & positions) in a FEN format.*/ parse arg seed CBs . /*obtain optional arguments from the CL*/ if datatype(seed,'W') then call random ,,seed /*SEED given for RANDOM repeatability? */ if CBs=='' | CBs=="," then CBs=1 /*CBs: number of generated ChessBoards*/ /* [↓] maybe display any # of boards. */ do boards=1 for abs(CBs) /* [↓] maybe display separator & title*/ if sign(CBs)\==CBs then do; say; say center(' board' boards" ", 79, '▒'); end @.=.; !.=@. /*initialize the chessboard to be empty*/ do p=1 for random(2, 32) /*generate a random number of chessmen.*/ if p<3 then call piece 'k' /*a king of each color. */ else call piece substr('bnpqr', random(1, 5), 1) end /*p*/ /* [↑] place a piece on the chessboard*/ call cb /*display the ChessBoard and its FEN.*/ end /*boards*/ /* [↑] CB ≡ ─ ─ */ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ cb: fen=; do r=8 for 8 by -1; $= /*the board rank (so far).*/ do f=8 for 8 by -1; $= $ || @.r.f /*append the board file. */ end /*f*/ say $ /*display the board rank. */ do e=8 for 8 by -1; $= changestr( copies(., e), $, e) /* . ≡ filler.*/ end /*e*/ fen= fen || $ || left('/', r\==1) /*append / if not 1st rank.*/ end /*r*/ /* [↑] append $ str to FEN*/ say /*display a blank sep. line*/ say 'FEN='fen "w - - 0 1" /*Forsyth─Edwards Notation.*/ return /* [↑] display chessboard.*/ /*──────────────────────────────────────────────────────────────────────────────────────*/ piece: parse arg x; if p//2 then upper x; arg ux /*use white if odd P.*/ if CBs<0 & p>2 then if random(1) then upper x /*CBs>0? Use balanced.*/ /*[↓] # isn't changed.*/ do #=0 by 0; r= random(1, 8); f= random(1, 8) /*random rank and file.*/ if @.r.f\==. then iterate /*is position occupied?*/ if (x=='p' & r==1) | (x=="P" & r==8) then iterate /*any promoting pawn? */ /*[↑] skip these pawns*/ if ux=='K' then do rr=r-1 for 3 /*[↓] neighbor ≡ king?*/ do ff=f-1 for 3; if !.rr.ff=='K' then iterate # /*king?*/ end /*rr*/ /*[↑] neighbor ≡ king?*/ end /*ff*/ /*[↑] we're all done. */ @.r.f= x /*put random piece. */  !.r.f= ux; return /* " " " upper*/ end /*#*/ /*#: isn't incremented.*/
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Go
Go
package main   import "fmt"   type vector = []float64 type matrix []vector   func (m matrix) inverse() matrix { le := len(m) for _, v := range m { if len(v) != le { panic("Not a square matrix") } } aug := make(matrix, le) for i := 0; i < le; i++ { aug[i] = make(vector, 2*le) copy(aug[i], m[i]) // augment by identity matrix to right aug[i][i+le] = 1 } aug.toReducedRowEchelonForm() inv := make(matrix, le) // remove identity matrix to left for i := 0; i < le; i++ { inv[i] = make(vector, le) copy(inv[i], aug[i][le:]) } return inv }   // note: this mutates the matrix in place func (m matrix) toReducedRowEchelonForm() { lead := 0 rowCount, colCount := len(m), len(m[0]) for r := 0; r < rowCount; r++ { if colCount <= lead { return } i := r   for m[i][lead] == 0 { i++ if rowCount == i { i = r lead++ if colCount == lead { return } } }   m[i], m[r] = m[r], m[i] if div := m[r][lead]; div != 0 { for j := 0; j < colCount; j++ { m[r][j] /= div } }   for k := 0; k < rowCount; k++ { if k != r { mult := m[k][lead] for j := 0; j < colCount; j++ { m[k][j] -= m[r][j] * mult } } } lead++ } }   func (m matrix) print(title string) { fmt.Println(title) for _, v := range m { fmt.Printf("% f\n", v) } fmt.Println() }   func main() { a := matrix{{1, 2, 3}, {4, 1, 6}, {7, 8, 9}} a.inverse().print("Inverse of A is:\n")   b := matrix{{2, -1, 0}, {-1, 2, -1}, {0, -1, 2}} b.inverse().print("Inverse of B is:\n") }
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Elixir
Elixir
defmodule General do def fizzbuzz(input) do [num | nwords] = String.split(input) max = String.to_integer(num) dict = Enum.chunk(nwords, 2) |> Enum.map(fn[n,word] -> {String.to_integer(n),word} end) Enum.each(1..max, fn i -> str = Enum.map_join(dict, fn {n,word} -> if rem(i,n)==0, do: word end) IO.puts if str=="", do: i, else: str end) end end   input = """ 105 3 Fizz 5 Buzz 7 Baxx """ General.fizzbuzz(input)
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Erlang
Erlang
  %%% @doc Implementation of General FizzBuzz %%% @see https://rosettacode.org/wiki/General_FizzBuzz -module(general_fizzbuzz). -export([run/2]). -spec run(N :: pos_integer(), Factors :: list(tuple())) -> ok.   fizzbuzz(N, [], []) -> integer_to_list(N); fizzbuzz(_, [], Result) -> lists:flatten(lists:reverse(Result)); fizzbuzz(N, Factors, Result) -> [{Factor, Output}|FactorsRest] = Factors,   NextResult = case N rem Factor of 0 -> [Output|Result]; _ -> Result end,   fizzbuzz(N, FactorsRest, NextResult).   run(N, Factors) -> lists:foreach( fun(S) -> io:format("~s~n", [S]) end, [fizzbuzz(X, Factors, []) || X <- lists:seq(1, N)] ).  
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#VBScript
VBScript
  'function arguments: "num" is the number to sequence and "return" is the value to return - "s" for the sequence or '"e" for the number elements. Function hailstone_sequence(num,return) n = num sequence = num elements = 1 Do Until n = 1 If n Mod 2 = 0 Then n = n / 2 Else n = (3 * n) + 1 End If sequence = sequence & " " & n elements = elements + 1 Loop Select Case return Case "s" hailstone_sequence = sequence Case "e" hailstone_sequence = elements End Select End Function   'test driving. 'show sequence for 27 WScript.StdOut.WriteLine "Sequence for 27: " & hailstone_sequence(27,"s") WScript.StdOut.WriteLine "Number of Elements: " & hailstone_sequence(27,"e") WScript.StdOut.WriteBlankLines(1) 'show the number less than 100k with the longest sequence count = 1 n_elements = 0 n_longest = "" Do While count < 100000 current_n_elements = hailstone_sequence(count,"e") If current_n_elements > n_elements Then n_elements = current_n_elements n_longest = "Number: " & count & " Length: " & n_elements End If count = count + 1 Loop WScript.StdOut.WriteLine "Number less than 100k with the longest sequence: " WScript.StdOut.WriteLine n_longest  
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#C.23
C#
using System; using System.Linq;   internal class Program { private static void Main() { Console.WriteLine(String.Concat(Enumerable.Range('a', 26).Select(c => (char)c))); } }
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Objective-C
Objective-C
  #import <Foundation/Foundation.h>   int main() { @autoreleasepool { NSLog(@"Hello, World!"); } }  
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Visual_Basic_.NET
Visual Basic .NET
Sub Swap(Of T)(ByRef a As T, ByRef b As T) Dim temp = a a = b b = temp End Sub
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Visual_FoxPro
Visual FoxPro
Since Visual FoxPro is not strongly typed, this will work with any data types.
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Icon_and_Unicon
Icon and Unicon
procedure main()   write("Non-cube Squares (21st to 30th):") every (k := 0, s := noncubesquares()) do if(k +:= 1) > 30 then break else write(20 < k," : ",s) end   procedure mthpower(m) #: generate i^m for i = 0,1,... while (/i := 0) | (i +:= 1) do suspend i^m end   procedure noncubesquares() #: filter for squares that aren't cubes cu := create mthpower(3) # co-expressions so that we can sq := create mthpower(2) # ... get our results where we need   repeat { if c === s then ( c := @cu , s := @sq ) else if s > c then c := @cu else { suspend s s := @sq } } end
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Ursa
Ursa
import "math" out (gcd 40902 24140) endl console
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Ursala
Ursala
#import nat   gcd = ~&B?\~&Y ~&alh^?\~&arh2faltPrXPRNfabt2RCQ @a ~&ar^?\~&al ^|R/~& ^/~&r remainder
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Lua
Lua
-- Insert 'str' into 't' at a random position from 'left' to 'right' function randomInsert (t, str, left, right) local pos repeat pos = math.random(left, right) until not t[pos] t[pos] = str return pos end   -- Generate a random Chess960 start position for white major pieces function chess960 () local t, b1, b2 = {} local kingPos = randomInsert(t, "K", 2, 7) randomInsert(t, "R", 1, kingPos - 1) randomInsert(t, "R", kingPos + 1, 8) b1 = randomInsert(t, "B", 1, 8) b2 = randomInsert(t, "B", 1, 8) while (b2 - b1) % 2 == 0 do t[b2] = false b2 = randomInsert(t, "B", 1, 8) end randomInsert(t, "Q", 1, 8) randomInsert(t, "N", 1, 8) randomInsert(t, "N", 1, 8) return t end   -- Main procedure math.randomseed(os.time()) print(table.concat(chess960()))
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#COBOL
COBOL
*> A subprogram taking no arguments and returning nothing. PROGRAM-ID. no-args PROTOTYPE. END PROGRAM no-args.   *> A subprogram taking two 8-digit numbers as arguments, and returning *> an 8-digit number. PROGRAM-ID. two-args PROTOTYPE. DATA DIVISION. LINKAGE SECTION. 01 arg-1 PIC 9(8). 01 arg-2 PIC 9(8). 01 ret PIC 9(8). PROCEDURE DIVISION USING arg-1, arg-2 RETURNING ret. END PROGRAM two-args.   *> A subprogram taking two optional arguments which are 8-digit *> numbers (passed by reference (the default and compulsory for *> optional arguments)). PROGRAM-ID. optional-args PROTOTYPE. DATA DIVISION. LINKAGE SECTION. 01 arg-1 PIC 9(8). 01 arg-2 PIC 9(8). PROCEDURE DIVISION USING OPTIONAL arg-1, OPTIONAL arg-2. END PROGRAM optional-args.   *> Standard COBOL does not support varargs or named parameters.   *> A function from another language, taking a 32-bit integer by *> value and returning a 32-bit integer (in Visual COBOL). PROGRAM-ID. foreign-func PROTOTYPE. OPTIONS. ENTRY-CONVENTION some-langauge. DATA DIVISION. WORKING-STORAGE SECTION. 01 arg PIC S9(9) USAGE COMP-5. 01 ret PIC S9(9) USAGE COMP-5. PROCEDURE DIVISION USING arg RETURNING ret. END PROGRAM foreign-func.
http://rosettacode.org/wiki/Functional_coverage_tree
Functional coverage tree
Functional coverage is a measure of how much a particular function of a system has been verified as correct. It is used heavily in tracking the completeness of the verification of complex System on Chip (SoC) integrated circuits, where it can also be used to track how well the functional requirements of the system have been verified. This task uses a sub-set of the calculations sometimes used in tracking functional coverage but uses a more familiar(?) scenario. Task Description The head of the clean-up crews for "The Men in a very dark shade of grey when viewed at night" has been tasked with managing the cleansing of two properties after an incident involving aliens. She arranges the task hierarchically with a manager for the crews working on each house who return with a breakdown of how they will report on progress in each house. The overall hierarchy of (sub)tasks is as follows, cleaning house1 bedrooms bathrooms bathroom1 bathroom2 outside lavatory attic kitchen living rooms lounge dining room conservatory playroom basement garage garden house2 upstairs bedrooms suite 1 suite 2 bedroom 3 bedroom 4 bathroom toilet attics groundfloor kitchen living rooms lounge dining room conservatory playroom wet room & toilet garage garden hot tub suite basement cellars wine cellar cinema The head of cleanup knows that her managers will report fractional completion of leaf tasks (tasks with no child tasks of their own), and she knows that she will want to modify the weight of values of completion as she sees fit. Some time into the cleaning, and some coverage reports have come in and she thinks see needs to weight the big house2 60-40 with respect to coverage from house1 She prefers a tabular view of her data where missing weights are assumed to be 1.0 and missing coverage 0.0. NAME_HIERARCHY |WEIGHT |COVERAGE | cleaning | | | house1 |40 | | bedrooms | |0.25 | bathrooms | | | bathroom1 | |0.5 | bathroom2 | | | outside_lavatory | |1 | attic | |0.75 | kitchen | |0.1 | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | |1 | basement | | | garage | | | garden | |0.8 | house2 |60 | | upstairs | | | bedrooms | | | suite_1 | | | suite_2 | | | bedroom_3 | | | bedroom_4 | | | bathroom | | | toilet | | | attics | |0.6 | groundfloor | | | kitchen | | | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | | | wet_room_&_toilet | | | garage | | | garden | |0.9 | hot_tub_suite | |1 | basement | | | cellars | |1 | wine_cellar | |1 | cinema | |0.75 | Calculation The coverage of a node in the tree is calculated as the weighted average of the coverage of its children evaluated bottom-upwards in the tree. The task is to calculate the overall coverage of the cleaning task and display the coverage at all levels of the hierarchy on this page, in a manner that visually shows the hierarchy, weights and coverage of all nodes. Extra Credit After calculating the coverage for all nodes, one can also calculate the additional/delta top level coverage that would occur if any (sub)task were to be fully covered from its current fractional coverage. This is done by multiplying the extra coverage that could be gained 1 − c o v e r a g e {\displaystyle 1-coverage} for any node, by the product of the `powers` of its parent nodes from the top down to the node. The power of a direct child of any parent is given by the power of the parent multiplied by the weight of the child divided by the sum of the weights of all the direct children. The pseudo code would be: method delta_calculation(this, power): sum_of_weights = sum(node.weight for node in children) this.delta = (1 - this.coverage) * power for node in self.children: node.delta_calculation(power * node.weight / sum_of_weights) return this.delta Followed by a call to: top.delta_calculation(power=1) Note: to aid in getting the data into your program you might want to use an alternative, more functional description of the starting data given on the discussion page.
#Go
Go
package main   import "fmt"   type FCNode struct { name string weight int coverage float64 children []*FCNode parent *FCNode }   func newFCN(name string, weight int, coverage float64) *FCNode { return &FCNode{name, weight, coverage, nil, nil} }   func (n *FCNode) addChildren(nodes []*FCNode) { for _, node := range nodes { node.parent = n n.children = append(n.children, node) } n.updateCoverage() }   func (n *FCNode) setCoverage(value float64) { if n.coverage != value { n.coverage = value // update any parent's coverage if n.parent != nil { n.parent.updateCoverage() } } }   func (n *FCNode) updateCoverage() { v1 := 0.0 v2 := 0 for _, node := range n.children { v1 += float64(node.weight) * node.coverage v2 += node.weight } n.setCoverage(v1 / float64(v2)) }   func (n *FCNode) show(level int) { indent := level * 4 nl := len(n.name) + indent fmt.Printf("%*s%*s  %3d | %8.6f |\n", nl, n.name, 32-nl, "|", n.weight, n.coverage) if len(n.children) == 0 { return } for _, child := range n.children { child.show(level + 1) } }   var houses = []*FCNode{ newFCN("house1", 40, 0), newFCN("house2", 60, 0), }   var house1 = []*FCNode{ newFCN("bedrooms", 1, 0.25), newFCN("bathrooms", 1, 0), newFCN("attic", 1, 0.75), newFCN("kitchen", 1, 0.1), newFCN("living_rooms", 1, 0), newFCN("basement", 1, 0), newFCN("garage", 1, 0), newFCN("garden", 1, 0.8), }   var house2 = []*FCNode{ newFCN("upstairs", 1, 0), newFCN("groundfloor", 1, 0), newFCN("basement", 1, 0), }   var h1Bathrooms = []*FCNode{ newFCN("bathroom1", 1, 0.5), newFCN("bathroom2", 1, 0), newFCN("outside_lavatory", 1, 1), }   var h1LivingRooms = []*FCNode{ newFCN("lounge", 1, 0), newFCN("dining_room", 1, 0), newFCN("conservatory", 1, 0), newFCN("playroom", 1, 1), }   var h2Upstairs = []*FCNode{ newFCN("bedrooms", 1, 0), newFCN("bathroom", 1, 0), newFCN("toilet", 1, 0), newFCN("attics", 1, 0.6), }   var h2Groundfloor = []*FCNode{ newFCN("kitchen", 1, 0), newFCN("living_rooms", 1, 0), newFCN("wet_room_&_toilet", 1, 0), newFCN("garage", 1, 0), newFCN("garden", 1, 0.9), newFCN("hot_tub_suite", 1, 1), }   var h2Basement = []*FCNode{ newFCN("cellars", 1, 1), newFCN("wine_cellar", 1, 1), newFCN("cinema", 1, 0.75), }   var h2UpstairsBedrooms = []*FCNode{ newFCN("suite_1", 1, 0), newFCN("suite_2", 1, 0), newFCN("bedroom_3", 1, 0), newFCN("bedroom_4", 1, 0), }   var h2GroundfloorLivingRooms = []*FCNode{ newFCN("lounge", 1, 0), newFCN("dining_room", 1, 0), newFCN("conservatory", 1, 0), newFCN("playroom", 1, 0), }   func main() { cleaning := newFCN("cleaning", 1, 0)   house1[1].addChildren(h1Bathrooms) house1[4].addChildren(h1LivingRooms) houses[0].addChildren(house1)   h2Upstairs[0].addChildren(h2UpstairsBedrooms) house2[0].addChildren(h2Upstairs) h2Groundfloor[1].addChildren(h2GroundfloorLivingRooms) house2[1].addChildren(h2Groundfloor) house2[2].addChildren(h2Basement) houses[1].addChildren(house2)   cleaning.addChildren(houses) topCoverage := cleaning.coverage fmt.Printf("TOP COVERAGE = %8.6f\n\n", topCoverage) fmt.Println("NAME HIERARCHY | WEIGHT | COVERAGE |") cleaning.show(0)   h2Basement[2].setCoverage(1) // change Cinema node coverage to 1 diff := cleaning.coverage - topCoverage fmt.Println("\nIf the coverage of the Cinema node were increased from 0.75 to 1") fmt.Print("the top level coverage would increase by ") fmt.Printf("%8.6f to %8.6f\n", diff, topCoverage+diff) h2Basement[2].setCoverage(0.75) // restore to original value if required }
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#Ada
Ada
function Gamma (X : Long_Float) return Long_Float is A : constant array (0..29) of Long_Float := ( 1.00000_00000_00000_00000, 0.57721_56649_01532_86061, -0.65587_80715_20253_88108, -0.04200_26350_34095_23553, 0.16653_86113_82291_48950, -0.04219_77345_55544_33675, -0.00962_19715_27876_97356, 0.00721_89432_46663_09954, -0.00116_51675_91859_06511, -0.00021_52416_74114_95097, 0.00012_80502_82388_11619, -0.00002_01348_54780_78824, -0.00000_12504_93482_14267, 0.00000_11330_27231_98170, -0.00000_02056_33841_69776, 0.00000_00061_16095_10448, 0.00000_00050_02007_64447, -0.00000_00011_81274_57049, 0.00000_00001_04342_67117, 0.00000_00000_07782_26344, -0.00000_00000_03696_80562, 0.00000_00000_00510_03703, -0.00000_00000_00020_58326, -0.00000_00000_00005_34812, 0.00000_00000_00001_22678, -0.00000_00000_00000_11813, 0.00000_00000_00000_00119, 0.00000_00000_00000_00141, -0.00000_00000_00000_00023, 0.00000_00000_00000_00002 ); Y  : constant Long_Float := X - 1.0; Sum : Long_Float := A (A'Last); begin for N in reverse A'First..A'Last - 1 loop Sum := Sum * Y + A (N); end loop; return 1.0 / Sum; end Gamma;
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#BASIC256
BASIC256
graphsize 150,125 fastgraphics color black rect 0,0,graphwidth,graphheight refresh   N = 10 # number of balls M = 5 # number of pins in last row dim ball(N,5) # (pos_x to center, level, x, y, direction} dim cnt(M+1)   rad = 6 slow = 0.3 diamond = {0,rad,rad,0,0,-rad,-rad,0} stepx = {rad/sqr(2),rad/2,rad/2,(1-1/sqr(2))*rad,0} stepy = {(1-1/sqr(2))*rad,rad/2,rad/2,rad/sqr(2),rad} CX = graphwidth/2 : CY = graphheight/2 iters = 0   # Draw pins for i = 1 to M y = 3*rad*i for j = 1 to i dx = (j-i\2-1)*4*rad + ((i-1)%2)*2*rad color purple stamp CX+dx,y,1.0,diamond color darkpurple stamp CX+dx,y,0.6,diamond next j next i gosub saverefresh   R = 0 : C = 0 font "Tahoma",10,50 do # Release ball if R<N then R = R + 1 ball[R-1,2] = CX : ball[R-1,3] = rad*(1-stepx[?]) : ball[R-1,4] = 0 # How many balls are released color black text 5,5,(R-1)+" balls" color green text 5,5,(R)+" balls" end if # Animate balls on this step for it = 0 to stepx[?]-1 for b = 0 to R-1 gosub moveball next b gosub saverefresh pause slow/stepx[?] next it # Where to go on the next step? for b = 0 to R-1 ball[b,1] = ball[b,1] + 1 if ball[b,1]<=M then if rand>=0.5 then ball[b,4] = 1 else ball[b,4] = -1 end if ball[b,0] = ball[b,0] + ball[b,4] else if ball[b,4]<>0 then gosub eraseball i = (ball[b,0]+M)/2 cnt[i] = cnt[i] + 1 ball[b,4] = 0 C = C + 1 end if end if next b # Draw counter color green y = 3*rad*(M+1) for j = 0 to M dx = (j-(M+1)\2)*4*rad + (M%2)*2*rad stamp CX+dx,y,{-1.2*rad,0,1.2*rad,0,1.2*rad,2*cnt[j],-1.2*rad,2*cnt[j]} next j gosub saverefresh until C >= N end   moveball: if ball[b,1]>M then return gosub eraseball if ball[b,4]<>0.0 then ball[b,2] = ball[b,2]+ball[b,4]*stepx[it] ball[b,3] = ball[b,3]+stepy[it] else ball[b,3] = ball[b,3]+rad end if gosub drawball   drawball: color darkgreen circle ball[b,2],ball[b,3],rad-1 color green circle ball[b,2],ball[b,3],rad-2 return   eraseball: color black circle ball[b,2],ball[b,3],rad-1 return   saverefresh: num$ = string(iters) for k = 1 to 4-length(num$) num$ = "0"+num$ next k imgsave num$+"-Galton_box_BASIC-256.png", "PNG" iters = iters + 1 refresh return
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#BBC_BASIC
BBC BASIC
maxBalls% = 10 DIM ballX%(maxBalls%), ballY%(maxBalls%)   VDU 23,22,180;400;8,16,16,128 ORIGIN 180,0 OFF   REM Draw the pins: GCOL 9 FOR row% = 1 TO 7 FOR col% = 1 TO row% CIRCLE FILL 40*col% - 20*row% - 20, 800 - 40*row%, 12 NEXT NEXT row%   REM Animate last% = 0 tick% = 0 GCOL 3,3 REPEAT IF RND(10) = 5 IF (tick% - last%) > 10 THEN FOR ball% = 1 TO maxBalls% IF ballY%(ball%) = 0 THEN ballX%(ball%) = 0 ballY%(ball%) = 800 last% = tick% EXIT FOR ENDIF NEXT ENDIF FOR ball% = 1 TO maxBalls% IF ballY%(ball%) CIRCLE FILL ballX%(ball%), ballY%(ball%), 12 IF POINT(ballX%(ball%),ballY%(ball%)-10) = 12 OR ballY%(ball%) < 12 THEN IF ballY%(ball%) > 500 END ballY%(ball%) = 0 ENDIF NEXT WAIT 2 FOR ball% = 1 TO maxBalls% IF ballY%(ball%) THEN CIRCLE FILL ballX%(ball%), ballY%(ball%), 12 ballY%(ball%) -= 4 IF POINT(ballX%(ball%),ballY%(ball%)-10) = 9 THEN ballX%(ball%) += 40 * (RND(2) - 1.5) ENDIF ENDIF NEXT tick% += 1 UNTIL FALSE
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Common_Lisp
Common Lisp
(defun first-digit (n) (parse-integer (string (char (write-to-string n) 0))))   (defun last-digit (n) (mod n 10))   (defun bookend-number (n) (+ (* 10 (first-digit n)) (last-digit n)))   (defun gapfulp (n) (and (>= n 100) (zerop (mod n (bookend-number n)))))   (defun gapfuls-in-range (start size) (loop for n from start with include = (gapfulp n) counting include into found if include collecting n until (= found size)))   (defun report-range (range) (destructuring-bind (start size) range (format t "The first ~a gapful numbers >= ~a:~% ~a~%~%" size start (gapfuls-in-range start size))))   (mapcar #'report-range '((1 30) (1000000 15) (1000000000 10)))  
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#Common_Lisp
Common Lisp
  (defmacro mapcar-1 (fn n list) "Maps a function of two parameters where the first one is fixed, over a list" `(mapcar #'(lambda (l) (funcall ,fn ,n l)) ,list) )     (defun gauss (m) (labels ((redc (m) ; Reduce to triangular form (if (null (cdr m)) m (cons (car m) (mapcar-1 #'cons 0 (redc (mapcar #'cdr (mapcar #'(lambda (r) (mapcar #'- (mapcar-1 #'* (caar m) r) (mapcar-1 #'* (car r) (car m)))) (cdr m)))))) )) (rev (m) ; Reverse each row except the last element (reverse (mapcar #'(lambda (r) (append (reverse (butlast r)) (last r))) m)) )) (catch 'result (let ((m1 (redc (rev (redc m))))) (reverse (mapcar #'(lambda (r) (let ((pivot (find-if-not #'zerop r))) (if pivot (/ (car (last r)) pivot) (throw 'result 'singular)))) m1)) ))))  
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Ruby
Ruby
  def hasNK( board, a, b ) for g in -1 .. 1 for f in -1 .. 1 aa = a + f; bb = b + g if aa.between?( 0, 7 ) && bb.between?( 0, 7 ) p = board[aa + 8 * bb] if p == "K" || p == "k"; return true; end end end end return false end def generateBoard( board, pieces ) while( pieces.length > 1 ) p = pieces[pieces.length - 1] pieces = pieces[0...-1] while( true ) a = rand( 8 ); b = rand( 8 ) if ( ( b == 0 || b == 7 ) && ( p == "P" || p == "p" ) ) || ( ( p == "k" || p == "K" ) && hasNK( board, a, b ) ); next; end if board[a + b * 8] == nil; break;end end board[a + b * 8] = p end end pieces = "ppppppppkqrrbbnnPPPPPPPPKQRRBBNN" for i in 0 .. 10 e = pieces.length - 1 while e > 0 p = rand( e ); t = pieces[e]; pieces[e] = pieces[p]; pieces[p] = t; e -= 1 end end board = Array.new( 64 ); generateBoard( board, pieces ) puts e = 0 for j in 0 .. 7 for i in 0 .. 7 if board[i + 8 * j] == nil; e += 1 else if e > 0; print( e ); e = 0; end print( board[i + 8 * j] ) end end if e > 0; print( e ); e = 0; end if j < 7; print( "/" ); end end print( " w - - 0 1\n" ) for j in 0 .. 7 for i in 0 .. 7 if board[i + j * 8] == nil; print( "." ) else print( board[i + j * 8] ); end end puts end  
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Haskell
Haskell
isMatrix xs = null xs || all ((== (length.head $ xs)).length) xs   isSquareMatrix xs = null xs || all ((== (length xs)).length) xs   mult:: Num a => [[a]] -> [[a]] -> [[a]] mult uss vss = map ((\xs -> if null xs then [] else foldl1 (zipWith (+)) xs). zipWith (\vs u -> map (u*) vs) vss) uss   matI::(Num a) => Int -> [[a]] matI n = [ [fromIntegral.fromEnum $ i == j | j <- [1..n]] | i <- [1..n]]   inversion xs = gauss xs (matI $ length xs)   gauss::[[Double]] -> [[Double]] -> [[Double]] gauss xs bs = map (map fromRational) $ solveGauss (toR xs) (toR bs) where toR = map $ map toRational   solveGauss:: (Fractional a, Ord a) => [[a]] -> [[a]] -> [[a]] solveGauss xs bs | null xs || null bs || length xs /= length bs || (not $ isSquareMatrix xs) || (not $ isMatrix bs) = [] | otherwise = uncurry solveTriangle $ triangle xs bs   solveTriangle::(Fractional a,Eq a) => [[a]] -> [[a]] -> [[a]] solveTriangle us _ | not.null.dropWhile ((/= 0).head) $ us = [] solveTriangle ([c]:as) (b:bs) = go as bs [map (/c) b] where val us vs ws = let u = head us in map (/u) $ zipWith (-) vs (head $ mult [tail us] ws) go [] _ zs = zs go _ [] zs = zs go (x:xs) (y:ys) zs = go xs ys $ (val x y zs):zs   triangle::(Num a, Ord a) => [[a]] -> [[a]] -> ([[a]],[[a]]) triangle xs bs = triang ([],[]) (xs,bs) where triang ts (_,[]) = ts triang ts ([],_) = ts triang (os,ps) zs = triang (us:os,cs:ps).unzip $ [(fun tus vs, fun cs es) | (v:vs,es) <- zip uss css,let fun = zipWith (\x y -> v*x - u*y)] where ((us@(u:tus)):uss,cs:css) = bubble zs   bubble::(Num a, Ord a) => ([[a]],[[a]]) -> ([[a]],[[a]]) bubble (xs,bs) = (go xs, go bs) where idmax = snd.maximum.flip zip [0..].map (abs.head) $ xs go ys = let (us,vs) = splitAt idmax ys in vs ++ us   main = do let a = [[1, 2, 3], [4, 1, 6], [7, 8, 9]] let b = [[2, -1, 0], [-1, 2, -1], [0, -1, 2]] putStrLn "inversion a =" mapM_ print $ inversion a putStrLn "\ninversion b =" mapM_ print $ inversion b
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Factor
Factor
USING: assocs combinators.extras io kernel math math.parser math.ranges prettyprint sequences splitting ; IN: rosetta-code.general-fizzbuzz   : prompt ( -- str ) ">" write readln ;   : get-factor ( -- seq ) prompt " " split first2 [ string>number ] dip { } 2sequence ;   : get-input ( -- assoc n ) prompt string>number [1,b] [ get-factor ] thrice { } 3sequence swap ;   : fizzbuzz ( assoc n -- ) swap dupd [ drop swap mod 0 = ] with assoc-filter dup empty? [ drop . ] [ nip values concat print ] if ;   : main ( -- ) get-input [ fizzbuzz ] with each ;   MAIN: main
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Forth
Forth
\ gfb.fs - generalized fizz buzz : times ( xt n -- ) BEGIN dup WHILE 1- over swap 2>r execute 2r> REPEAT 2drop ; \ 'Domain Specific Language' compiling words \ -- First comment: stack-effect at compile-time \ -- Second comment: stack efect of compiled sequence : ]+[ ( u ca u -- ) ( u f -- u f' ) 2>r >r ] ]] over [[ r> ]] literal mod 0= IF [[ 2r> ]] sliteral type 1+ THEN [ [[ ; : ]fb ( -- xt ) ( u f -- u+1 ) ]] IF space ELSE dup u. THEN 1+ ; [[ ; : fb[ ( -- ) ( u -- u 0  ;'u' is START-NUMBER ) :noname 0 ]] literal [ [[ ; \ Usage: START-NUMBER COMPILING-SEQUENCE U times drop ( INCREASED-NUBER ) \ Example: \ 1 fb[ 3 s" fizz" ]+[ 5 s" buzz" ]+[ 7 s" dizz" ]+[ ]fb 40 times drop  
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Visual_Basic
Visual Basic
Option Explicit Dim flag As Boolean ' true to print values Sub main() Dim longest As Long, n As Long Dim i As Long, value As Long ' Task 1: flag = True i = 27 Debug.Print "The hailstone sequence has length of "; i; " is "; hailstones(i) ' Task 2: flag = False longest = 0 For i = 1 To 99999 If longest < hailstones(i) Then longest = hailstones(i) value = i End If Next i Debug.Print value; " has the longest sequence of "; longest End Sub 'main Function hailstones(n As Long) As Long Dim m As Long, p As Long Dim m1 As Long, m2 As Long, m3 As Long, m4 As Long If flag Then Debug.Print "The sequence for"; n; "is: "; p = 1 m = n If flag Then Debug.Print m; While m > 1 p = p + 1 If (m Mod 2) = 0 Then m = m / 2 Else m = 3 * m + 1 End If If p <= 4 Then If flag Then Debug.Print m; m4 = m3 m3 = m2 m2 = m1 m1 = m Wend If flag Then If p <= 4 Then Debug.Print ElseIf p = 5 Then Debug.Print m1 ElseIf p = 6 Then Debug.Print m2; m1 ElseIf p = 7 Then Debug.Print m3; m2; m1 ElseIf p = 8 Then Debug.Print m4; m3; m2; m1 Else Debug.Print "..."; m4; m3; m2; m1 End If End If hailstones = p End Function 'hailstones
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#C.2B.2B
C++
#include <string> #include <numeric>   int main() { std::string lower(26,' ');   std::iota(lower.begin(), lower.end(), 'a'); }
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Clojure
Clojure
(map char (range (int \a) (inc (int \z))))
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#OCaml
OCaml
print_endline "Hello world!"
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Wart
Wart
(swap! x y)
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Wren
Wren
var swap = Fn.new { |l| var t = l[0] l[0] = l[1] l[1] = t }   var a = 6 var b = 3 var c = [a, b] swap.call(c) // pass a list instead of individual variables a = c[0] // unpack b = c[1] // ditto System.print("a is now %(a)") System.print("b is now %(b)") System.print()   // all user defined classes are reference types class Box { construct new(v) { _v = v } v { _v } v=(value) { _v = value } }   // by passing boxed arguments we can mutate them var boxSwap = Fn.new { |a, b| var t = a.v a.v = b.v b.v = t }   var d = Box.new(4) var e = Box.new(8) boxSwap.call(d, e) d = d.v // unbox e = e.v // ditto System.print("d is now %(d)") System.print("e is now %(e)")
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#J
J
coclass 'mthPower' N=: 0 create=: 3 :0 M=: y ) next=: 3 :0 n=. N N=: N+1 n^M )
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#V
V
[gcd [0 >] [dup rollup %] while pop ].
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#VBA
VBA
Function gcd(u As Long, v As Long) As Long Dim t As Long Do While v t = u u = v v = t Mod v Loop gcd = u End Function
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
Print[StringJoin[ RandomChoice[ Select[Union[ Permutations[{"\[WhiteKing]", "\[WhiteQueen]", "\[WhiteRook]", "\[WhiteRook]", "\[WhiteBishop]", "\[WhiteBishop]", "\[WhiteKnight]", "\[WhiteKnight]"}]], MatchQ[#, {___, "\[WhiteRook]", ___, "\[WhiteKing]", ___, "\[WhiteRook]", ___}] && OddQ[Subtract @@ Flatten[Position[#, "\[WhiteBishop]"]]] &]]]];
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#MiniScript
MiniScript
// placeholder knights rank = ["♘"] * 8   // function to get a random free space from a to b, inclusive randFree = function(a, b) free = [] for i in range(a, b) if rank[i] == "♘" then free.push i end for return free[rnd * free.len] end function   // place the king kingIdx = randFree(1, 6) rank[kingIdx] = "♔"   // place rooks rank[randFree(0, kingIdx - 1)] = "♖" rank[randFree(kingIdx + 1, 7)] = "♖"   // place bishops bishIdx = randFree(0, 7) rank[bishIdx] = "♗" while true i = randFree(0, 7) if i % 2 != bishIdx % 2 then break end while rank[i] = "♗"   // place queen rank[randFree(0, 7)] = "♕"   print join(rank, " ")
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Common_Lisp
Common Lisp
  (declaim (inline no-args)) (declaim (inline one-arg)) (declaim (inline two-args)) (declaim (inline optional-args))   (defun no-args () (format nil "no arguments!"))   (defun one-arg (x) ; inserts the value of x into a string (format nil "~a" x))   (defun two-args (x y) ; same as function `one-arg', but with two arguments (format nil "~a ~a" x y))   (defun optional-args (x &optional y) ; optional args are denoted with &optional beforehand ; same as function `two-args', but if y is not given it just prints NIL (format nil "~a ~a~%" x y))     (no-args) ;=> "no arguments!"   (one-arg 1) ;=> "1"   (two-args 1 "example") ;=> "1 example"   (optional-args 1.0) ;=> "1.0 NIL"   (optional-args 1.0 "example") ;=> "1.0 example"  
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#D
D
/// Declare a function with no arguments that returns an integer. int noArgs();   /// Declare a function with no arguments that returns an integer. int twoArgs(int a, int b);   /// Parameter names are optional in a prototype definition. int twoArgs2(int, int);   /// An ellipsis can be used to declare a function that accepts /// C-style varargs. int anyArgs(...);   /// One mandatory integer argument followed by C-style varargs. int atLeastOneArg(int, ...);   /// Declare a function that accepts any number of integers. void anyInts(int[] a...);   /// Declare a function that accepts D-style varargs. void anyArgs2(TArgs...)(TArgs args);   /// Declare a function that accepts two or more D-style varargs. void anyArgs3(TArgs...)(TArgs args) if (TArgs.length > 2);   /// Currently D doesn't support named arguments.   /// One implementation. int twoArgs(int a, int b) { return a + b; }   interface SomeInterface { void foo(); void foo(int, int);   // Varargs void foo(...); // C-style. void foo(int[] a...); void bar(T...)(T args); // D-style.   // Optional arguments are only supported if a default is provided, // the default arg(s) has/have to be at the end of the args list. void foo(int a, int b = 10); }   void main() {}
http://rosettacode.org/wiki/Functional_coverage_tree
Functional coverage tree
Functional coverage is a measure of how much a particular function of a system has been verified as correct. It is used heavily in tracking the completeness of the verification of complex System on Chip (SoC) integrated circuits, where it can also be used to track how well the functional requirements of the system have been verified. This task uses a sub-set of the calculations sometimes used in tracking functional coverage but uses a more familiar(?) scenario. Task Description The head of the clean-up crews for "The Men in a very dark shade of grey when viewed at night" has been tasked with managing the cleansing of two properties after an incident involving aliens. She arranges the task hierarchically with a manager for the crews working on each house who return with a breakdown of how they will report on progress in each house. The overall hierarchy of (sub)tasks is as follows, cleaning house1 bedrooms bathrooms bathroom1 bathroom2 outside lavatory attic kitchen living rooms lounge dining room conservatory playroom basement garage garden house2 upstairs bedrooms suite 1 suite 2 bedroom 3 bedroom 4 bathroom toilet attics groundfloor kitchen living rooms lounge dining room conservatory playroom wet room & toilet garage garden hot tub suite basement cellars wine cellar cinema The head of cleanup knows that her managers will report fractional completion of leaf tasks (tasks with no child tasks of their own), and she knows that she will want to modify the weight of values of completion as she sees fit. Some time into the cleaning, and some coverage reports have come in and she thinks see needs to weight the big house2 60-40 with respect to coverage from house1 She prefers a tabular view of her data where missing weights are assumed to be 1.0 and missing coverage 0.0. NAME_HIERARCHY |WEIGHT |COVERAGE | cleaning | | | house1 |40 | | bedrooms | |0.25 | bathrooms | | | bathroom1 | |0.5 | bathroom2 | | | outside_lavatory | |1 | attic | |0.75 | kitchen | |0.1 | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | |1 | basement | | | garage | | | garden | |0.8 | house2 |60 | | upstairs | | | bedrooms | | | suite_1 | | | suite_2 | | | bedroom_3 | | | bedroom_4 | | | bathroom | | | toilet | | | attics | |0.6 | groundfloor | | | kitchen | | | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | | | wet_room_&_toilet | | | garage | | | garden | |0.9 | hot_tub_suite | |1 | basement | | | cellars | |1 | wine_cellar | |1 | cinema | |0.75 | Calculation The coverage of a node in the tree is calculated as the weighted average of the coverage of its children evaluated bottom-upwards in the tree. The task is to calculate the overall coverage of the cleaning task and display the coverage at all levels of the hierarchy on this page, in a manner that visually shows the hierarchy, weights and coverage of all nodes. Extra Credit After calculating the coverage for all nodes, one can also calculate the additional/delta top level coverage that would occur if any (sub)task were to be fully covered from its current fractional coverage. This is done by multiplying the extra coverage that could be gained 1 − c o v e r a g e {\displaystyle 1-coverage} for any node, by the product of the `powers` of its parent nodes from the top down to the node. The power of a direct child of any parent is given by the power of the parent multiplied by the weight of the child divided by the sum of the weights of all the direct children. The pseudo code would be: method delta_calculation(this, power): sum_of_weights = sum(node.weight for node in children) this.delta = (1 - this.coverage) * power for node in self.children: node.delta_calculation(power * node.weight / sum_of_weights) return this.delta Followed by a call to: top.delta_calculation(power=1) Note: to aid in getting the data into your program you might want to use an alternative, more functional description of the starting data given on the discussion page.
#Haskell
Haskell
{-# LANGUAGE OverloadedStrings #-}   import Data.Bifunctor (first) import Data.Bool (bool) import Data.Char (isSpace) import qualified Data.Text as T import qualified Data.Text.IO as T import qualified Data.Text.Read as T import Data.Tree (Forest, Tree (..), foldTree) import Numeric (showFFloat) import System.Directory (doesFileExist)   ----------------- FUNCTIONAL COVERAGE TREE ---------------   data Coverage = Coverage { name :: T.Text, weight :: Float, coverage :: Float, share :: Float } deriving (Show)   --------------------------- TEST ------------------------- fp = "./coverageOutline.txt"   main :: IO () main = doesFileExist fp >>= bool (print $ "File not found: " <> fp) (T.readFile fp >>= T.putStrLn . updatedCoverageOutline)   ----------------- UPDATED COVERAGE OUTLINE --------------- updatedCoverageOutline :: T.Text -> T.Text updatedCoverageOutline s = let delimiter = "|" indentedLines = T.lines s columnNames = init $ tokenizeWith delimiter ( head indentedLines ) in T.unlines [ tabulation delimiter (columnNames <> ["SHARE OF RESIDUE"]), indentedLinesFromTree " " (showCoverage delimiter) $ withResidueShares 1.0 $ foldTree weightedCoverage (parseTreeFromOutline delimiter indentedLines) ]   ------ WEIGHTED COVERAGE AND SHARES OF REMAINING WORK ---- weightedCoverage :: Coverage -> Forest Coverage -> Tree Coverage weightedCoverage x xs = let cws = ((,) . coverage <*> weight) . rootLabel <$> xs totalWeight = foldr ((+) . snd) 0 cws in Node ( x { coverage = foldr (\(c, w) a -> (c * w) + a) (coverage x) cws / bool 1 totalWeight (0 < totalWeight) } ) xs   withResidueShares :: Float -> Tree Coverage -> Tree Coverage withResidueShares shareOfTotal tree = let go fraction node = let forest = subForest node weights = weight . rootLabel <$> forest weightTotal = sum weights nodeRoot = rootLabel node in Node ( nodeRoot { share = fraction * (1 - coverage nodeRoot) } ) ( zipWith go ((fraction *) . (/ weightTotal) <$> weights) forest ) in go shareOfTotal tree   ---------------------- OUTLINE PARSE --------------------- parseTreeFromOutline :: T.Text -> [T.Text] -> Tree Coverage parseTreeFromOutline delimiter indentedLines = partialRecord . tokenizeWith delimiter <$> head ( forestFromLineIndents $ indentLevelsFromLines $ tail indentedLines )   forestFromLineIndents :: [(Int, T.Text)] -> [Tree T.Text] forestFromLineIndents pairs = let go [] = [] go ((n, s) : xs) = let (firstTreeLines, rest) = span ((n <) . fst) xs in Node s (go firstTreeLines) : go rest in go pairs   indentLevelsFromLines :: [T.Text] -> [(Int, T.Text)] indentLevelsFromLines xs = let pairs = T.span isSpace <$> xs indentUnit = foldr ( \x a -> let w = (T.length . fst) x in bool a w (w < a && 0 < w) ) (maxBound :: Int) pairs in first (flip div indentUnit . T.length) <$> pairs   partialRecord :: [T.Text] -> Coverage partialRecord xs = let [name, weightText, coverageText] = take 3 (xs <> repeat "") in Coverage { name = name, weight = defaultOrRead 1.0 weightText, coverage = defaultOrRead 0.0 coverageText, share = 0.0 }   defaultOrRead :: Float -> T.Text -> Float defaultOrRead n txt = either (const n) fst $ T.rational txt   tokenizeWith :: T.Text -> T.Text -> [T.Text] tokenizeWith delimiter = fmap T.strip . T.splitOn delimiter   -------- SERIALISATION OF TREE TO TABULATED OUTLINE ------ indentedLinesFromTree :: T.Text -> (T.Text -> a -> T.Text) -> Tree a -> T.Text indentedLinesFromTree tab showRoot tree = let go indent node = showRoot indent (rootLabel node) : (subForest node >>= go (T.append tab indent)) in T.unlines $ go "" tree   showCoverage :: T.Text -> T.Text -> Coverage -> T.Text showCoverage delimiter indent x = tabulation delimiter ( [T.append indent (name x), T.pack (showN 0 (weight x))] <> (T.pack . showN 4 <$> ([coverage, share] <*> [x])) )   tabulation :: T.Text -> [T.Text] -> T.Text tabulation delimiter = T.intercalate (T.append delimiter " ") . zipWith (`T.justifyLeft` ' ') [31, 9, 9, 9]   justifyRight :: Int -> a -> [a] -> [a] justifyRight n c = (drop . length) <*> (replicate n c <>)   showN :: Int -> Float -> String showN p n = justifyRight 7 ' ' (showFFloat (Just p) n "")
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#ACL2
ACL2
(in-package "ACL2")   (set-state-ok t)   (defun read-all-objects (limit channel state) (mv-let (eof obj state) (read-object channel state) (if (or eof (zp limit)) (mv nil state) (mv-let (so-far state) (read-all-objects (- limit 1) channel state) (mv (cons obj so-far) state)))))   (defun list-starters (xs) (cond ((endp xs) nil) ((consp (first xs)) (append (if (symbolp (first (first xs))) (list (first (first xs))) nil) (list-starters (rest (first xs))) (list-starters (rest xs)))) (t (list-starters (rest xs)))))   (defun invoked-functions (filename state) (mv-let (channel state) (open-input-channel filename :object state) (mv-let (code state) (read-all-objects 1000 channel state) (mv (list-starters code) state))))   (defun increment-for (key alist) (cond ((endp alist) (list (cons key 1))) ((equal key (car (first alist))) (cons (cons key (1+ (cdr (first alist)))) (rest alist))) (t (cons (first alist) (increment-for key (rest alist))))))   (defun symbol-freq-table (symbols) (if (endp symbols) nil (increment-for (first symbols) (symbol-freq-table (rest symbols)))))   (defun insert-freq-table (pair alist) (cond ((endp alist) (list pair)) ((> (cdr pair) (cdr (first alist))) (cons pair alist)) (t (cons (first alist) (insert-freq-table pair (rest alist))))))   (defun isort-freq-table (alist) (if (endp alist) nil (insert-freq-table (first alist) (isort-freq-table (rest alist)))))   (defun main (state) (mv-let (fns state) (invoked-functions "function-freq.lisp" state) (mv (take 10 (isort-freq-table (symbol-freq-table fns))) state)))
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#ALGOL_68
ALGOL 68
# Coefficients used by the GNU Scientific Library # []LONG REAL p = ( LONG 0.99999 99999 99809 93, LONG 676.52036 81218 851, -LONG 1259.13921 67224 028, LONG 771.32342 87776 5313, -LONG 176.61502 91621 4059, LONG 12.50734 32786 86905, -LONG 0.13857 10952 65720 12, LONG 9.98436 95780 19571 6e-6, LONG 1.50563 27351 49311 6e-7);   PROC lanczos gamma = (LONG REAL in z)LONG REAL: ( # Reflection formula # LONG REAL z := in z; IF z < LONG 0.5 THEN long pi / (long sin(long pi*z)*lanczos gamma(1-z)) ELSE z -:= 1; LONG REAL x := p[1]; FOR i TO UPB p - 1 DO x +:= p[i+1]/(z+i) OD; LONG REAL t = z + UPB p - LONG 1.5; long sqrt(2*long pi) * t**(z+LONG 0.5) * long exp(-t) * x FI );   PROC taylor gamma = (LONG REAL x)LONG REAL: BEGIN # good for values between 0 and 1 # []LONG REAL a = ( LONG 1.00000 00000 00000 00000, LONG 0.57721 56649 01532 86061, -LONG 0.65587 80715 20253 88108, -LONG 0.04200 26350 34095 23553, LONG 0.16653 86113 82291 48950, -LONG 0.04219 77345 55544 33675, -LONG 0.00962 19715 27876 97356, LONG 0.00721 89432 46663 09954, -LONG 0.00116 51675 91859 06511, -LONG 0.00021 52416 74114 95097, LONG 0.00012 80502 82388 11619, -LONG 0.00002 01348 54780 78824, -LONG 0.00000 12504 93482 14267, LONG 0.00000 11330 27231 98170, -LONG 0.00000 02056 33841 69776, LONG 0.00000 00061 16095 10448, LONG 0.00000 00050 02007 64447, -LONG 0.00000 00011 81274 57049, LONG 0.00000 00001 04342 67117, LONG 0.00000 00000 07782 26344, -LONG 0.00000 00000 03696 80562, LONG 0.00000 00000 00510 03703, -LONG 0.00000 00000 00020 58326, -LONG 0.00000 00000 00005 34812, LONG 0.00000 00000 00001 22678, -LONG 0.00000 00000 00000 11813, LONG 0.00000 00000 00000 00119, LONG 0.00000 00000 00000 00141, -LONG 0.00000 00000 00000 00023, LONG 0.00000 00000 00000 00002 ); LONG REAL y = x - 1; LONG REAL sum := a [UPB a]; FOR n FROM UPB a - 1 DOWNTO LWB a DO sum := sum * y + a [n] OD; 1/sum END # taylor gamma #;   LONG REAL long e = long exp(1);   PROC sterling gamma = (LONG REAL n)LONG REAL: ( # improves for values much greater then 1 # long sqrt(2*long pi/n)*(n/long e)**n );   PROC factorial = (LONG INT n)LONG REAL: ( IF n=0 OR n=1 THEN 1 ELIF n=2 THEN 2 ELSE n*factorial(n-1) FI );   REF[]LONG REAL fm := NIL;   PROC sponge gamma = (LONG REAL x)LONG REAL: ( INT a = 12; # alter to get required precision # REF []LONG REAL fm := NIL; LONG REAL res;   IF fm :=: REF[]LONG REAL(NIL) THEN fm := HEAP[0:a-1]LONG REAL; fm[0] := long sqrt(LONG 2*long pi); FOR k TO a-1 DO fm[k] := (((k-1) MOD 2=0) | 1 | -1) * long exp(a-k) * (a-k) **(k-LONG 0.5) / factorial(k-1) OD FI; res := fm[0]; FOR k TO a-1 DO res +:= fm[k] / ( x + k ) OD; res *:= long exp(-(x+a)) * (x+a)**(x + LONG 0.5); res/x );   FORMAT real fmt = $g(-real width, real width - 2)$; FORMAT long real fmt16 = $g(-17, 17 - 2)$; # accurate to about 16 decimal places #   []STRING methods = ("Genie", "Lanczos", "Sponge", "Taylor","Stirling");   printf(($11xg12xg12xg13xg13xgl$,methods));   FORMAT sample fmt = $"gamma("g(-3,1)")="f(real fmt)n(UPB methods-1)(", "f(long real fmt16))l$; FORMAT sqr sample fmt = $"gamma("g(-3,1)")**2="f(real fmt)n(UPB methods-1)(", "f(long real fmt16))l$; FORMAT sample exp fmt = $"gamma("g(-3)")="g(-15,11,0)n(UPB methods-1)(","g(-18,14,0))l$;   PROC sample = (LONG REAL x)[]LONG REAL: (gamma(SHORTEN x), lanczos gamma(x), sponge gamma(x), taylor gamma(x), sterling gamma(x));   FOR i FROM 1 TO 20 DO LONG REAL x = i / LONG 10; printf((sample fmt, x, sample(x))); IF i = 5 THEN # insert special case of a half # printf((sqr sample fmt, x, gamma(SHORTEN x)**2, lanczos gamma(x)**2, sponge gamma(x)**2, taylor gamma(x)**2, sterling gamma(x)**2)) FI OD; FOR x FROM 10 BY 10 TO 70 DO printf((sample exp fmt, x, sample(x))) OD
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#C
C
#include <stdio.h> #include <stdlib.h> #include <string.h>   #define BALLS 1024 int n, w, h = 45, *x, *y, cnt = 0; char *b;   #define B(y, x) b[(y)*w + x] #define C(y, x) ' ' == b[(y)*w + x] #define V(i) B(y[i], x[i]) inline int rnd(int a) { return (rand()/(RAND_MAX/a))%a; }   void show_board() { int i, j; for (puts("\033[H"), i = 0; i < h; i++, putchar('\n')) for (j = 0; j < w; j++, putchar(' ')) printf(B(i, j) == '*' ? C(i - 1, j) ? "\033[32m%c\033[m" : "\033[31m%c\033[m" : "%c", B(i, j)); }   void init() { int i, j; puts("\033[H\033[J"); b = malloc(w * h); memset(b, ' ', w * h);   x = malloc(sizeof(int) * BALLS * 2); y = x + BALLS;   for (i = 0; i < n; i++) for (j = -i; j <= i; j += 2) B(2 * i+2, j + w/2) = '*'; srand(time(0)); }   void move(int idx) { int xx = x[idx], yy = y[idx], c, kill = 0, sl = 3, o = 0;   if (yy < 0) return; if (yy == h - 1) { y[idx] = -1; return; }   switch(c = B(yy + 1, xx)) { case ' ': yy++; break; case '*': sl = 1; default: if (xx < w - 1 && C(yy, xx + 1) && C(yy + 1, xx + 1)) if (!rnd(sl++)) o = 1; if (xx && C(yy, xx - 1) && C(yy + 1, xx - 1)) if (!rnd(sl++)) o = -1; if (!o) kill = 1; xx += o; }   c = V(idx); V(idx) = ' '; idx[y] = yy, idx[x] = xx; B(yy, xx) = c; if (kill) idx[y] = -1; }   int run(void) { static int step = 0; int i; for (i = 0; i < cnt; i++) move(i); if (2 == ++step && cnt < BALLS) { step = 0; x[cnt] = w/2; y[cnt] = 0; if (V(cnt) != ' ') return 0; V(cnt) = rnd(80) + 43; cnt++; } return 1; }   int main(int c, char **v) { if (c < 2 || (n = atoi(v[1])) <= 3) n = 5; if (n >= 20) n = 20; w = n * 2 + 1; init();   do { show_board(), usleep(60000); } while (run());   return 0; }
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Crystal
Crystal
struct Int def gapful? a = self.to_s.chars.map(&.to_i) self % (a.first*10 + a.last) == 0 end end   specs = {100 => 30, 1_000_000 => 15, 1_000_000_000 => 10, 7123 => 25}   specs.each do |start, count| puts "first #{count} gapful numbers >= #{start}:" puts (start..).each.select(&.gapful?).first(count).to_a, "\n" end
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#D
D
import std.stdio, std.math, std.algorithm, std.range, std.numeric, std.typecons;   Tuple!(double[],"x", string,"err") gaussPartial(in double[][] a0, in double[] b0) pure /*nothrow*/ in { assert(a0.length == a0[0].length); assert(a0.length == b0.length); assert(a0.all!(row => row.length == a0[0].length)); } body { enum eps = 1e-6; immutable m = b0.length;   // Make augmented matrix. //auto a = a0.zip(b0).map!(c => c[0] ~ c[1]).array; // Not mutable. auto a = a0.zip(b0).map!(c => [] ~ c[0] ~ c[1]).array;   // Wikipedia algorithm from Gaussian elimination page, // produces row-eschelon form. foreach (immutable k; 0 .. a.length) { // Find pivot for column k and swap. a[k .. m].minPos!((x, y) => x[k] > y[k]).front.swap(a[k]); if (a[k][k].abs < eps) return typeof(return)(null, "singular");   // Do for all rows below pivot. foreach (immutable i; k + 1 .. m) { // Do for all remaining elements in current row. a[i][k+1 .. m+1] -= a[k][k+1 .. m+1] * (a[i][k] / a[k][k]);   a[i][k] = 0; // Fill lower triangular matrix with zeros. } }   // End of WP algorithm. Now back substitute to get result. auto x = new double[m]; foreach_reverse (immutable i; 0 .. m) x[i] = (a[i][m] - a[i][i+1 .. m].dotProduct(x[i+1 .. m])) / a[i][i];   return typeof(return)(x, null); }   void main() { // The test case result is correct to this tolerance. enum eps = 1e-13;   // Common RC example. Result computed with rational arithmetic // then converted to double, and so should be about as close to // correct as double represention allows. immutable a = [[1.00, 0.00, 0.00, 0.00, 0.00, 0.00], [1.00, 0.63, 0.39, 0.25, 0.16, 0.10], [1.00, 1.26, 1.58, 1.98, 2.49, 3.13], [1.00, 1.88, 3.55, 6.70, 12.62, 23.80], [1.00, 2.51, 6.32, 15.88, 39.90, 100.28], [1.00, 3.14, 9.87, 31.01, 97.41, 306.02]]; immutable b = [-0.01, 0.61, 0.91, 0.99, 0.60, 0.02];   immutable r = gaussPartial(a, b); if (!r.err.empty) return writeln("Error: ", r.err); r.x.writeln;   immutable result = [-0.01, 1.602790394502114, -1.6132030599055613, 1.2454941213714368, -0.4909897195846576, 0.065760696175232]; foreach (immutable i, immutable xi; result) if (abs(r.x[i] - xi) > eps) return writeln("Out of tolerance: ", r.x[i], " ", xi); }
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Rust
Rust
use std::fmt::Write;   use rand::{Rng, distributions::{Distribution, Standard}};   const EMPTY: u8 = b'.';   #[derive(Clone, Debug)] struct Board { grid: [[u8; 8]; 8], }   impl Distribution<Board> for Standard { fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Board { let mut board = Board::empty(); board.place_kings(rng); board.place_pieces(rng, b"PPPPPPPP", true); board.place_pieces(rng, b"pppppppp", true); board.place_pieces(rng, b"RNBQBNR", false); board.place_pieces(rng, b"rnbqbnr", false); board } }   impl Board { fn empty() -> Self { Board { grid: [[EMPTY; 8]; 8] } }   fn fen(&self) -> String { let mut fen = String::new(); let mut count_empty = 0; for row in &self.grid { for &ch in row { print!("{} ", ch as char); if ch == EMPTY { count_empty += 1; } else { if count_empty > 0 { write!(fen, "{}", count_empty).unwrap(); count_empty = 0; } fen.push(ch as char); } } if count_empty > 0 { write!(fen, "{}", count_empty).unwrap(); count_empty = 0; } fen.push('/'); println!(); } fen.push_str(" w - - 0 1"); fen }   fn place_kings<R: Rng + ?Sized>(&mut self, rng: &mut R) { loop { let r1: i8 = rng.gen_range(0, 8); let c1: i8 = rng.gen_range(0, 8); let r2: i8 = rng.gen_range(0, 8); let c2: i8 = rng.gen_range(0, 8); if r1 != r2 && (r1 - r2).abs() > 1 && (c1 - c2).abs() > 1 { self.grid[r1 as usize][c1 as usize] = b'K'; self.grid[r2 as usize][c2 as usize] = b'k'; return; } } }   fn place_pieces<R: Rng + ?Sized>(&mut self, rng: &mut R, pieces: &[u8], is_pawn: bool) { let num_to_place = rng.gen_range(0, pieces.len()); for &piece in pieces.iter().take(num_to_place) { let mut r = rng.gen_range(0, 8); let mut c = rng.gen_range(0, 8); while self.grid[r][c] != EMPTY || (is_pawn && (r == 7 || r == 0)) { r = rng.gen_range(0, 8); c = rng.gen_range(0, 8); } self.grid[r][c] = piece; } } }   fn main() { let b: Board = rand::random(); println!("{}", b.fen()); }
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Scala
Scala
import scala.math.abs import scala.util.Random   object RandomFen extends App { val rand = new Random   private def createFen = { val grid = Array.ofDim[Char](8, 8)   def placeKings(grid: Array[Array[Char]]): Unit = { var r1, c1, r2, c2 = 0 do { r1 = rand.nextInt(8) c1 = rand.nextInt(8) r2 = rand.nextInt(8) c2 = rand.nextInt(8) } while (r1 == r2 || abs(r1 - r2) <= 1 || abs(c1 - c2) <= 1) grid(r1)(c1) = 'K' grid(r2)(c2) = 'k' }   def placePieces(grid: Array[Array[Char]], pieces: String, isPawn: Boolean): Unit = { val numToPlace = rand.nextInt(pieces.length)   for (n <- 0 until numToPlace) { var r, c = 0 do { r = rand.nextInt(8) c = rand.nextInt(8) } while (grid(r)(c) != 0 || (isPawn && (r == 7 || r == 0))) grid(r)(c) = pieces(n) } }   def toFen(grid: Array[Array[Char]]) = { val fen = new StringBuilder var countEmpty = 0 for (r <- grid.indices) { for (c <- grid.indices) { val ch = grid(r)(c) print(f"${if (ch == 0) '.' else ch}%2c ") if (ch == 0) countEmpty += 1 else { if (countEmpty > 0) { fen.append(countEmpty) countEmpty = 0 } fen.append(ch) } } if (countEmpty > 0) { fen.append(countEmpty) countEmpty = 0 } fen.append("/") println() } fen.append(" w - - 0 1").toString }   placeKings(grid) placePieces(grid, "PPPPPPPP", isPawn = true) placePieces(grid, "pppppppp", isPawn = true) placePieces(grid, "RNBQBNR", isPawn = false) placePieces(grid, "rnbqbnr", isPawn = false) toFen(grid) }   println(createFen)   }
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#J
J
require 'math/misc/linear' augmentR_I1=: ,. e.@i.@# NB. augment matrix on the right with its Identity matrix matrix_invGJ=: # }."1 [: gauss_jordan@augmentR_I1
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#FreeBASIC
FreeBASIC
' version 01-03-2018 ' compile with: fbc -s console   Dim As UInteger f(), factor, c, i, n Dim As Integer max Dim As String w(), word Dim As boolean flag   Do Input "Enter maximum number, if number < 1 then the program wil end ", max If max < 1 Then Exit Do   Print While c = 0 Or c > max Input "Total number of factors ", c Wend c -= 1 ReDim f(c), w(c)   Print For i = 0 To c Input "Enter factor and word, separated by a comma ", factor, word f(i) = factor w(i) = word Next     While flag = FALSE flag = TRUE For n = 0 To c-1 For i = 1 To c If f(n) > f(i) Then flag = FALSE Swap f(n), f(i) Swap w(n), w(i) End If Next Next Wend   For n = 1 To max flag = FALSE For i = 0 To c If n Mod f(i) = 0 Then flag = TRUE Print w(i); End If Next Print IIf(flag , "", Str(n)) Next   Exit Do Loop   ' empty keyboard buffer While Inkey <> "" : Wend Print : Print "hit any key to end program" Sleep End