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http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #ALGOL_68 | ALGOL 68 |
PROC cf = (INT steps, PROC (INT) INT a, PROC (INT) INT b) REAL:
BEGIN
REAL result;
result := 0;
FOR n FROM steps BY -1 TO 1 DO
result := b(n) / (a(n) + result)
OD;
a(0) + result
END;
PROC asqr2 = (INT n) INT: (n = 0 | 1 | 2);
PROC bsqr2 = (INT n) INT: 1;
PROC anap = (INT n) INT: (n = 0 | 2 | n);
PROC bnap = (INT n) INT: (n = 1 | 1 | n - 1);
PROC api = (INT n) INT: (n = 0 | 3 | 6);
PROC bpi = (INT n) INT: (n = 1 | 1 | (2 * n - 1) ** 2);
INT precision = 10000;
print (("Precision: ", precision, newline));
print (("Sqr(2): ", cf(precision, asqr2, bsqr2), newline));
print (("Napier: ", cf(precision, anap, bnap), newline));
print (("Pi: ", cf(precision, api, bpi)))
|
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #REXX | REXX | /*REXX program converts a rational fraction [n/m] (or nnn.ddd) to it's lowest terms.*/
numeric digits 10 /*use ten decimal digits of precision. */
parse arg orig 1 n.1 "/" n.2; if n.2='' then n.2=1 /*get the fraction.*/
if n.1='' then call er 'no argument specified.'
do j=1 for 2; if \datatype(n.j, 'N') then call er "argument isn't numeric:" n.j
end /*j*/ /* [↑] validate arguments: n.1 n.2 */
if n.2=0 then call er "divisor can't be zero." /*Whoa! We're dividing by zero ! */
say 'old =' space(orig) /*display the original fraction. */
say 'new =' rat(n.1/n.2) /*display the result ──► terminal. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
er: say; say '***error***'; say; say arg(1); say; exit 13
/*──────────────────────────────────────────────────────────────────────────────────────*/
rat: procedure; parse arg x 1 _x,y; if y=='' then y = 10**(digits()-1)
b=0; g=0; a=1; h=1 /* [↑] Y is the tolerance.*/
do while a<=y & g<=y; n=trunc(_x)
_=a; a=n*a+b; b=_
_=g; g=n*g+h; h=_
if n=_x | a/g=x then do; if a>y | g>y then iterate
b=a; h=g; leave
end
_x=1/(_x-n)
end /*while*/
if h==1 then return b /*don't return number ÷ by 1.*/
return b'/'h /*proper or improper fraction. */ |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #DWScript | DWScript | var src = "foobar"
var dst = src |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Dyalect | Dyalect | var src = "foobar"
var dst = src |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #beeswax | beeswax | #>%f# #>%f# #f%<##>%f#
pq":X~7~ :X@~++8~8@:X:X@~-~4~.+~8@T_
## ## #### #`K0[`}`D2[`}BF3< <
>{` wk, `>g?"p{` d, `>g?"p{` hr, `>g?"p{` min, `>g"b{` sec, `b
> d > d > d > d |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #C.23 | C# | interface IEatable
{
void Eat();
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #C.2B.2B | C++ | template<typename T> //Detection helper struct
struct can_eat //Detects presence of non-const member function void eat()
{
private:
template<typename U, void (U::*)()> struct SFINAE {};
template<typename U> static char Test(SFINAE<U, &U::eat>*);
template<typename U> static int Test(...);
public:
static constexpr bool value = sizeof(Test<T>(0)) == sizeof(char);
};
struct potato
{ void eat(); };
struct brick
{};
template<typename T>
class FoodBox
{
//Using static assertion to prohibit non-edible types
static_assert(can_eat<T>::value, "Only edible items are allowed in foodbox");
//Rest of class definition
};
int main()
{
FoodBox<potato> lunch;
//Following leads to compile-time error
//FoodBox<brick> practical_joke;
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Common_Lisp | Common Lisp | (defclass food () ())
(defclass inedible-food (food) ())
(defclass edible-food (food) ())
(defgeneric eat (foodstuff)
(:documentation "Eat the foodstuff."))
(defmethod eat ((foodstuff edible-food))
"A specialized method for eating edible-food."
(format nil "Eating ~w." foodstuff))
(defun eatable-p (thing)
"Returns true if there are eat methods defined for thing."
(not (endp (compute-applicable-methods #'eat (list thing)))))
(deftype eatable ()
"Eatable objects are those satisfying eatable-p."
'(satisfies eatable-p))
(defun make-food-box (extra-type &rest array-args)
"Returns an array whose element-type is (and extra-type food).
array-args should be suitable for MAKE-ARRAY, and any provided
element-type keyword argument is ignored."
(destructuring-bind (dimensions &rest array-args) array-args
(apply 'make-array dimensions
:element-type `(and ,extra-type food)
array-args)))
(defun make-eatable-food-box (&rest array-args)
"Return an array whose elements are declared to be of type (and
eatable food)."
(apply 'make-food-box 'eatable array-args)) |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #ALGOL_68 | ALGOL 68 | BEGIN # find sequences of primes where the gaps between the elements #
# are strictly ascending/descending #
# reurns a list of primes up to n #
PROC prime list = ( INT n )[]INT:
BEGIN
# sieve the primes to n #
INT no = 0, yes = 1;
[ 1 : n ]INT p;
p[ 1 ] := no; p[ 2 ] := yes;
FOR i FROM 3 BY 2 TO n DO p[ i ] := yes OD;
FOR i FROM 4 BY 2 TO n DO p[ i ] := no OD;
FOR i FROM 3 BY 2 TO ENTIER sqrt( n ) DO
IF p[ i ] = yes THEN FOR s FROM i * i BY i + i TO n DO p[ s ] := no OD FI
OD;
# replace the sieve with a list #
INT p pos := 0;
FOR i TO n DO IF p[ i ] = yes THEN p[ p pos +:= 1 ] := i FI OD;
p[ 1 : p pos ]
END # prime list # ;
# shos the results of a search #
PROC show sequence = ( []INT primes, STRING seq name, INT seq start, seq length )VOID:
BEGIN
print( ( " The longest sequence of primes with "
, seq name
, " differences contains "
, whole( seq length, 0 )
, " primes"
, newline
, " First such sequence (differences in brackets):"
, newline
, " "
)
);
print( ( whole( primes[ seq start ], 0 ) ) );
FOR p FROM seq start + 1 TO seq start + ( seq length - 1 ) DO
print( ( " (", whole( ABS( primes[ p ] - primes[ p - 1 ] ), 0 ), ") ", whole( primes[ p ], 0 ) ) )
OD;
print( ( newline ) )
END # show seuence # ;
# find the longest sequence of primes where the successive differences are ascending/descending #
PROC find sequence = ( []INT primes, BOOL ascending, REF INT seq start, seq length )VOID:
BEGIN
seq start := seq length := 0;
INT start diff = IF ascending THEN 0 ELSE UPB primes + 1 FI;
FOR p FROM LWB primes TO UPB primes DO
INT prev diff := start diff;
INT length := 1;
FOR s FROM p + 1 TO UPB primes
WHILE INT diff = ABS ( primes[ s ] - primes[ s - 1 ] );
IF ascending THEN diff > prev diff ELSE diff < prev diff FI
DO
length +:= 1;
prev diff := diff
OD;
IF length > seq length THEN
# found a longer sequence #
seq length := length;
seq start := p
FI
OD
END # find sequence #;
INT max number = 1 000 000;
[]INT primes = prime list( max number );
INT asc length := 0;
INT asc start := 0;
INT desc length := 0;
INT desc start := 0;
find sequence( primes, TRUE, asc start, asc length );
find sequence( primes, FALSE, desc start, desc length );
# show the sequences #
print( ( "For primes up to ", whole( max number, 0 ), newline ) );
show sequence( primes, "ascending", asc start, asc length );
show sequence( primes, "descending", desc start, desc length )
END |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #Arturo | Arturo | calc: function [f, n][
[a, b, temp]: 0.0
loop n..1 'i [
[a, b]: call f @[i]
temp: b // a + temp
]
[a, b]: call f @[0]
return a + temp
]
sqrt2: function [n][
(n > 0)? -> [2.0, 1.0] -> [1.0, 1.0]
]
napier: function [n][
a: (n > 0)? -> to :floating n -> 2.0
b: (n > 1)? -> to :floating n-1 -> 1.0
@[a, b]
]
Pi: function [n][
a: (n > 0)? -> 6.0 -> 3.0
b: ((2 * to :floating n)-1) ^ 2
@[a, b]
]
print calc 'sqrt2 20
print calc 'napier 15
print calc 'Pi 10000 |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Ruby | Ruby | > '0.9054054 0.518518 0.75'.split.each { |d| puts "%s %s" % [d, Rational(d)] }
0.9054054 4527027/5000000
0.518518 259259/500000
0.75 3/4
=> ["0.9054054", "0.518518", "0.75"] |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Rust | Rust |
extern crate rand;
extern crate num;
use num::Integer;
use rand::Rng;
fn decimal_to_rational (mut n : f64) -> [isize;2] {
//Based on Farey sequences
assert!(n.is_finite());
let flag_neg = n < 0.0;
if flag_neg { n = n*(-1.0) }
if n < std::f64::MIN_POSITIVE { return [0,1] }
if (n - n.round()).abs() < std::f64::EPSILON { return [n.round() as isize, 1] }
let mut a : isize = 0;
let mut b : isize = 1;
let mut c : isize = n.ceil() as isize;
let mut d : isize = 1;
let aux1 = isize::max_value()/2;
while c < aux1 && d < aux1 {
let aux2 : f64 = (a as f64 + c as f64)/(b as f64 + d as f64);
if (n - aux2).abs() < std::f64::EPSILON { break }
if n > aux2 {
a = a + c;
b = b + d;
} else {
c = a + c;
d = b + d;
}
}
// Make sure that the fraction is irreducible
let gcd = (a+c).gcd(&(b+d));
if flag_neg { [-(a + c)/gcd, (b + d)/gcd] } else { [(a + c)/gcd, (b + d)/gcd] }
}
#[test]
fn test1 () {
// Test the function with 1_000_000 random decimal numbers
let mut rng = rand::thread_rng();
for _i in 1..1_000_000 {
let number = rng.gen::<f64>();
let result = decimal_to_rational(number);
assert!((number - (result[0] as f64)/(result[1] as f64)).abs() < std::f64::EPSILON);
assert!(result[0].gcd(&result[1]) == 1);
}
}
fn main () {
let mut rng = rand::thread_rng();
for _i in 1..10 {
let number = rng.gen::<f64>();
let result = decimal_to_rational(number);
if result[1] == 1 { println!("{} -> {}", number, result[0]) } else { println!("{} -> {}/{}", number, result[0], result[1]) }
}
for i in [-0.9054054, 0.518518, -0.75, 0.5185185185185185, -0.9054054054054054, 0.0, 1.0, 2.0].iter() {
let result = decimal_to_rational(*i as f64);
if result[1] == 1 { println!("{} = {}",*i, result[0]) } else { println!("{} = {}/{}", *i, result[0], result[1]) }
}
}
|
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #D.C3.A9j.C3.A0_Vu | Déjà Vu | local :orgininal "this is the original"
local :scopy concat( original "" )
!. scopy |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #E | E | a$ = "hello"
b$ = a$ |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #Befunge | Befunge | &>:"<"%\"O{rq"**+\"<"/:"<"%\"r<|":*+*5-\v
v-7*"l~"/7\"d"\%7:/*83\+*:"xD"\%*83:/"<"<
> \:! #v_v#-#<",",#$48*#<,#<.#<>#_:"~"%,v
^_@#:$$< > .02g92p ^ ^!:/"~"< |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Crystal | Crystal | class Apple
def eat
end
end
class Carrot
def eat
end
end
class FoodBox(T)
def initialize(@data : Array(T))
{% if T.union? %}
{% raise "All items should be eatable" unless T.union_types.all? &.has_method?(:eat) %}
{% else %}
{% raise "Items should be eatable" unless T.has_method?(:eat) %}
{% end %}
end
end
FoodBox.new([Apple.new, Apple.new])
FoodBox.new([Apple.new, Carrot.new])
FoodBox.new([Apple.new, Carrot.new, 123]) |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #D | D | enum IsEdible(T) = is(typeof(T.eat));
struct FoodBox(T) if (IsEdible!T) {
T[] food;
alias food this;
}
struct Carrot {
void eat() {}
}
static struct Car {}
void main() {
FoodBox!Carrot carrotsBox; // OK
carrotsBox ~= Carrot(); // Adds a carrot
//FoodBox!Car carsBox; // Not allowed
} |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #C.23 | C# | using System.Linq;
using System.Collections.Generic;
using TG = System.Tuple<int, int>;
using static System.Console;
class Program
{
static void Main(string[] args)
{
const int mil = (int)1e6;
foreach (var amt in new int[] { 1, 2, 6, 12, 18 })
{
int lmt = mil * amt, lg = 0, ng, d, ld = 0;
var desc = new string[] { "A", "", "De" };
int[] mx = new int[] { 0, 0, 0 },
bi = new int[] { 0, 0, 0 },
c = new int[] { 2, 2, 2 };
WriteLine("For primes up to {0:n0}:", lmt);
var pr = PG.Primes(lmt).ToArray();
for (int i = 0; i < pr.Length; i++)
{
ng = pr[i].Item2; d = ng.CompareTo(lg) + 1;
if (ld == d)
c[2 - d]++;
else
{
if (c[d] > mx[d]) { mx[d] = c[d]; bi[d] = i - mx[d] - 1; }
c[d] = 2;
}
ld = d; lg = ng;
}
for (int r = 0; r <= 2; r += 2)
{
Write("{0}scending, found run of {1} consecutive primes:\n {2} ",
desc[r], mx[r] + 1, pr[bi[r]++].Item1);
foreach (var itm in pr.Skip(bi[r]).Take(mx[r]))
Write("({0}) {1} ", itm.Item2, itm.Item1); WriteLine(r == 0 ? "" : "\n");
}
}
}
}
class PG
{
public static IEnumerable<TG> Primes(int lim)
{
bool[] flags = new bool[lim + 1];
int j = 3, lj = 2;
for (int d = 8, sq = 9; sq <= lim; j += 2, sq += d += 8)
if (!flags[j])
{
yield return new TG(j, j - lj);
lj = j;
for (int k = sq, i = j << 1; k <= lim; k += i) flags[k] = true;
}
for (; j <= lim; j += 2)
if (!flags[j])
{
yield return new TG(j, j - lj);
lj = j;
}
}
} |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #ATS | ATS | #include
"share/atspre_staload.hats"
//
(* ****** ****** *)
//
(*
** a coefficient function creates double values from in paramters
*)
typedef coeff_f = int -> double
//
(*
** a continued fraction is described by a record of two coefficent
** functions a and b
*)
typedef frac = @{a= coeff_f, b= coeff_f}
//
(* ****** ****** *)
fun calc
(
f: frac, n: int
) : double = let
//
(*
** recursive definition of the approximation
*)
fun loop
(
n: int, r: double
) : double =
(
if n = 0
then f.a(0) + r
else loop (n - 1, f.b(n) / (f.a(n) + r))
// end of [if]
)
//
in
loop (n, 0.0)
end // end of [calc]
(* ****** ****** *)
val sqrt2 = @{
a= lam (n: int): double => if n = 0 then 1.0 else 2.0
,
b= lam (n: int): double => 1.0
} (* end of [val] *)
val napier = @{
a= lam (n: int): double => if n = 0 then 2.0 else 1.0 * n
,
b= lam (n: int): double => if n = 1 then 1.0 else n - 1.0
} (* end of [val] *)
val pi = @{
a= lam (n: int): double => if n = 0 then 3.0 else 6.0
,
b= lam (n: int): double => let val x = 2.0 * n - 1 in x * x end
}
(* ****** ****** *)
implement
main0 () =
(
println! ("sqrt2 = ", calc(sqrt2, 100));
println! ("napier = ", calc(napier, 100));
println! (" pi = ", calc( pi , 100));
) (* end of [main0] *) |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Scala | Scala | import org.apache.commons.math3.fraction.BigFraction
object Number2Fraction extends App {
val n = Array(0.750000000, 0.518518000, 0.905405400,
0.142857143, 3.141592654, 2.718281828, -0.423310825, 31.415926536)
for (d <- n)
println(f"$d%-12s : ${new BigFraction(d, 0.00000002D, 10000)}%s")
} |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Seed7 | Seed7 | $ include "seed7_05.s7i";
include "bigrat.s7i";
const proc: main is func
begin
writeln(bigRational parse "0.9(054)");
writeln(bigRational parse "0.(518)");
writeln(bigRational parse "0.75");
writeln(bigRational parse "3.(142857)");
writeln(bigRational parse "0.(8867924528301)");
writeln(bigRational parse "0.(846153)");
writeln(bigRational parse "0.9054054");
writeln(bigRational parse "0.518518");
writeln(bigRational parse "0.14285714285714");
writeln(bigRational parse "3.14159265358979");
writeln(bigRational parse "2.718281828");
writeln(bigRational parse "31.415926536");
writeln(bigRational parse "0.000000000");
end func; |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #EasyLang | EasyLang | a$ = "hello"
b$ = a$ |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #EchoLisp | EchoLisp |
(define-syntax-rule (string-copy s) (string-append s)) ;; copy = append nothing
→ #syntax:string-copy
(define s "abc")
(define t (string-copy s))
t → "abc"
(eq? s t) → #t ;; same reference, same object
|
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #C | C | /*
* Program seconds2string, C89 version.
*
* Read input from argv[1] or stdin, write output to stdout.
*/
#define _CRT_SECURE_NO_WARNINGS /* unlocks printf in Microsoft Visual Studio */
#include <stdio.h>
#include <stdlib.h>
/*
* Converting the number of seconds in a human-readable string.
* It is worth noting that direct output to stdout would be even simpler.
*/
char* seconds2string(unsigned long seconds)
{
int i;
const unsigned long s = 1;
const unsigned long m = 60 * s;
const unsigned long h = 60 * m;
const unsigned long d = 24 * h;
const unsigned long w = 7 * d;
const unsigned long coeff[5] = { w, d, h, m, s };
const char units[5][4] = { "wk", "d", "hr", "min", "sec" };
static char buffer[256];
char* ptr = buffer;
for ( i = 0; i < 5; i++ )
{
unsigned long value;
value = seconds / coeff[i];
seconds = seconds % coeff[i];
if ( value )
{
if ( ptr != buffer )
ptr += sprintf(ptr, ", ");
ptr += sprintf(ptr,"%lu %s",value,units[i]);
}
}
return buffer;
}
/*
* Main function for seconds2string program.
*/
int main(int argc, char argv[])
{
unsigned long seconds;
if ( (argc < 2) && scanf( "%lu", &seconds )
|| (argc >= 2) && sscanf( argv[1], "%lu", & seconds ) )
{
printf( "%s\n", seconds2string(seconds) );
return EXIT_SUCCESS;
}
return EXIT_FAILURE;
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #E | E | /** Guard accepting only objects with an 'eat' method */
def Eatable {
to coerce(specimen, ejector) {
if (Ref.isNear(specimen) && specimen.__respondsTo("eat", 0)) {
return specimen
} else {
throw.eject(ejector, `inedible: $specimen`)
}
}
}
def makeFoodBox() {
return [].diverge(Eatable) # A guard-constrained list
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Eiffel | Eiffel |
deferred class
EATABLE
feature -- Basic operations
eat
-- Eat this eatable substance
deferred
end
end
|
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #F.23 | F# | type ^a FoodBox // a generic type FoodBox
when ^a: (member eat: unit -> string) // with an explicit member constraint on ^a,
(items:^a list) = // a one-argument constructor
member inline x.foodItems = items // and a public read-only property
// a class type that fullfills the member constraint
type Banana() =
member x.eat() = "I'm eating a banana."
// an instance of a Banana FoodBox
let someBananas = FoodBox [Banana(); Banana()] |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #C.2B.2B | C++ | #include <cstdint>
#include <iostream>
#include <vector>
#include <primesieve.hpp>
void print_diffs(const std::vector<uint64_t>& vec) {
for (size_t i = 0, n = vec.size(); i != n; ++i) {
if (i != 0)
std::cout << " (" << vec[i] - vec[i - 1] << ") ";
std::cout << vec[i];
}
std::cout << '\n';
}
int main() {
std::cout.imbue(std::locale(""));
std::vector<uint64_t> asc, desc;
std::vector<std::vector<uint64_t>> max_asc, max_desc;
size_t max_asc_len = 0, max_desc_len = 0;
uint64_t prime;
const uint64_t limit = 1000000;
for (primesieve::iterator pi; (prime = pi.next_prime()) < limit; ) {
size_t alen = asc.size();
if (alen > 1 && prime - asc[alen - 1] <= asc[alen - 1] - asc[alen - 2])
asc.erase(asc.begin(), asc.end() - 1);
asc.push_back(prime);
if (asc.size() >= max_asc_len) {
if (asc.size() > max_asc_len) {
max_asc_len = asc.size();
max_asc.clear();
}
max_asc.push_back(asc);
}
size_t dlen = desc.size();
if (dlen > 1 && prime - desc[dlen - 1] >= desc[dlen - 1] - desc[dlen - 2])
desc.erase(desc.begin(), desc.end() - 1);
desc.push_back(prime);
if (desc.size() >= max_desc_len) {
if (desc.size() > max_desc_len) {
max_desc_len = desc.size();
max_desc.clear();
}
max_desc.push_back(desc);
}
}
std::cout << "Longest run(s) of ascending prime gaps up to " << limit << ":\n";
for (const auto& v : max_asc)
print_diffs(v);
std::cout << "\nLongest run(s) of descending prime gaps up to " << limit << ":\n";
for (const auto& v : max_desc)
print_diffs(v);
return 0;
} |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #AutoHotkey | AutoHotkey | sqrt2_a(n) ; function definition is as simple as that
{
return n?2.0:1.0
}
sqrt2_b(n)
{
return 1.0
}
napier_a(n)
{
return n?n:2.0
}
napier_b(n)
{
return n>1.0?n-1.0:1.0
}
pi_a(n)
{
return n?6.0:3.0
}
pi_b(n)
{
return (2.0*n-1.0)**2.0 ; exponentiation operator
}
calc(f,expansions)
{
r:=0,i:=expansions
; A nasty trick: the names of the two coefficient functions are generated dynamically
; a dot surrounded by spaces means string concatenation
f_a:=f . "_a",f_b:=f . "_b"
while i>0 {
; You can see two dynamic function calls here
r:=%f_b%(i)/(%f_a%(i)+r)
i--
}
return %f_a%(0)+r
}
Msgbox, % "sqrt 2 = " . calc("sqrt2", 1000) . "`ne = " . calc("napier", 1000) . "`npi = " . calc("pi", 1000) |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Sidef | Sidef | say 0.75.as_frac #=> 3/4
say 0.518518.as_frac #=> 259259/500000
say 0.9054054.as_frac #=> 4527027/5000000 |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Tcl | Tcl | #!/usr/bin/env tclsh
proc dbl2frac {dbl {eps 0.000001}} {
for {set den 1} {$den<1024} {incr den} {
set num [expr {round($dbl*$den)}]
if {abs(double($num)/$den - $dbl) < $eps} break
}
list $num $den
}
#-------------------- That's all... the rest is the test suite
if {[file tail $argv0] eq [file tail [info script]]} {
foreach {test -> expected} {
{dbl2frac 0.518518} -> {42 81}
{dbl2frac 0.75} -> {3 4}
{dbl2frac 0.9054054} -> {67 74}
} {
catch $test res
if {$res ne $expected} {
puts "$test -> $res, expected $expected"
}
}
} |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #EDSAC_order_code | EDSAC order code | [ Copy a string
=============
A program for the EDSAC
Copies the source string into storage
tank 6, which is assumed to be free,
and then prints it from there
Works with Initial Orders 2 ]
T56K
GK
[ 0 ] A34@ [ copy the string ]
[ 1 ] T192F
[ 2 ] H34@
C32@
S32@
E17@
T31@
A@
A33@
T@
A1@
A33@
T1@
A2@
A33@
T2@
E@
[ 17 ] O192F [ print the copy ]
[ 18 ] H192F
C32@
S32@
E30@
T31@
A17@
A33@
T17@
A18@
A33@
T18@
E17@
[ 30 ] ZF
[ 31 ] PF
[ 32 ] PD
[ 33 ] P1F
[ 34 ] *F
RF
OF
SF
EF
TF
TF
AF
!F
CF
OF
DF
ED
EZPF |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Elena | Elena |
var src := "Hello";
var dst := src; // copying the reference
var copy := src.clone(); // copying the content
|
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #C.23 | C# | using System;
using System.Collections.Generic;
using System.Linq;
namespace ConvertSecondsToCompoundDuration
{
class Program
{
static void Main( string[] args )
{
foreach ( string arg in args )
{
int duration ;
bool isValid = int.TryParse( arg , out duration ) ;
if ( !isValid ) { Console.Error.WriteLine( "ERROR: Not an integer: {0}" , arg ) ; }
if ( duration < 0 ) { Console.Error.WriteLine( "ERROR: duration must be non-negative" , arg ) ; }
Console.WriteLine();
Console.WriteLine( "{0:#,##0} seconds ==> {1}" , duration , FormatAsDuration(duration) ) ;
}
}
private static string FormatAsDuration( int duration )
{
if ( duration < 0 ) throw new ArgumentOutOfRangeException("duration") ;
return string.Join( ", " , GetDurationParts(duration) ) ;
}
private static IEnumerable<string> GetDurationParts( int duration )
{
var parts = new[]
{
new { Name="wk" , Length = 7*24*60*60*1 , } ,
new { Name="d" , Length = 24*60*60*1 , } ,
new { Name="h" , Length = 60*60*1 , } ,
new { Name="m" , Length = 60*1 , } ,
new { Name="s" , Length = 1 , } ,
} ;
foreach ( var part in parts )
{
int n = Math.DivRem( duration , part.Length , out duration ) ;
if ( n > 0 ) yield return string.Format( "{0} {1}" , n , part.Name ) ;
}
}
}
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Forth | Forth | include FMS-SI.f
include FMS-SILib.f
:class Eatable
:m eat ." successful eat " ;m
;class
\ FoodBox is defined without inspecting for the eat message
:class FoodBox
object-list eatable-types
:m init: eatable-types init: ;m
:m add: ( obj -- )
dup is-kindOf Eatable
if eatable-types add:
else drop ." not an eatable type "
then ;m
:m test
begin eatable-types each:
while eat
repeat ;m
;class
FoodBox aFoodBox
Eatable aEatable
aEatable aFoodBox add: \ add the e1 object to the object-list
aFoodBox test \ => successful eat
:class brick
:m eat cr ." successful eat " ;m
;class
brick abrick \ create an object that is not eatable
abrick aFoodBox add: \ => not an eatable type
:class apple <super Eatable
;class
apple anapple
anapple aFoodBox add:
aFoodBox test \ => successful eat successful eat
|
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Fortran | Fortran |
module cg
implicit none
type, abstract :: eatable
end type eatable
type, extends(eatable) :: carrot_t
end type carrot_t
type :: brick_t; end type brick_t
type :: foodbox
class(eatable), allocatable :: food
contains
procedure, public :: add_item => add_item_fb
end type foodbox
contains
subroutine add_item_fb(this, f)
class(foodbox), intent(inout) :: this
class(eatable), intent(in) :: f
allocate(this%food, source=f)
end subroutine add_item_fb
end module cg
program con_gen
use cg
implicit none
type(carrot_t) :: carrot
type(brick_t) :: brick
type(foodbox) :: fbox
! Put a carrot into the foodbox
call fbox%add_item(carrot)
! Try to put a brick in - results in a compiler error
call fbox%add_item(brick)
end program con_gen
|
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Go | Go | type eatable interface {
eat()
} |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #F.23 | F# |
// Longest ascending and decending sequences of difference between consecutive primes: Nigel Galloway. April 5th., 2021
let fN g fW=primes32()|>Seq.takeWhile((>)g)|>Seq.pairwise|>Seq.fold(fun(n,i,g)el->let w=fW el in match w>n with true->(w,el::i,g) |_->(w,[el],if List.length i>List.length g then i else g))(0,[],[])
for i in [1;2;6;12;18;100] do let _,_,g=fN(i*1000000)(fun(n,g)->g-n) in printfn "Longest ascending upto %d000000->%d:" i (g.Length+1); g|>List.rev|>List.iter(fun(n,g)->printf "%d (%d) %d " n (g-n) g); printfn ""
let _,_,g=fN(i*1000000)(fun(n,g)->n-g) in printfn "Longest decending upto %d000000->%d:" i (g.Length+1); g|>List.rev|>List.iter(fun(n,g)->printf "%d (%d) %d " n (g-n) g); printfn ""
|
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Factor | Factor | USING: arrays assocs formatting grouping io kernel literals math
math.primes math.statistics sequences sequences.extras
tools.memory.private ;
<< CONSTANT: limit 1,000,000 >>
CONSTANT: primes $[ limit primes-upto ]
: run ( n quot -- seq quot )
[ primes ] [ <clumps> ] [ ] tri*
'[ differences _ monotonic? ] ; inline
: max-run ( quot -- n )
1 swap '[ 1 + dup _ run find drop ] loop 1 - ; inline
: runs ( quot -- seq )
[ max-run ] keep run filter ; inline
: .run ( seq -- )
dup differences [ [ commas ] map ] bi@
[ "(" ")" surround ] map 2array round-robin " " join print ;
: .runs ( quot -- )
[ runs ] keep [ < ] = "rising" "falling" ? limit commas
"Largest run(s) of %s gaps between primes less than %s:\n"
printf [ .run ] each ; inline
[ < ] [ > ] [ .runs nl ] bi@ |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #Axiom | Axiom | get(obj) == convergents(obj).1000 -- utility to extract the 1000th value
get continuedFraction(1, repeating [1], repeating [2]) :: Float
get continuedFraction(2, cons(1,[i for i in 1..]), [i for i in 1..]) :: Float
get continuedFraction(3, [i^2 for i in 1.. by 2], repeating [6]) :: Float |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #BBC_BASIC | BBC BASIC | *FLOAT64
@% = &1001010
PRINT "SQR(2) = " ; FNcontfrac(1, 1, "2", "1")
PRINT " e = " ; FNcontfrac(2, 1, "N", "N")
PRINT " PI = " ; FNcontfrac(3, 1, "6", "(2*N+1)^2")
END
REM a$ and b$ are functions of N
DEF FNcontfrac(a0, b1, a$, b$)
LOCAL N, expr$
REPEAT
N += 1
expr$ += STR$(EVAL(a$)) + "+" + STR$(EVAL(b$)) + "/("
UNTIL LEN(expr$) > (65500 - N)
= a0 + b1 / EVAL (expr$ + "1" + STRING$(N, ")")) |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Vala | Vala | struct Fraction {
public long d;
public long n;
}
Fraction rat_approx(double f, long md) {
long a;
long[] h = {0, 1, 0};
long[] k = {1, 0, 0};
long x, d, n = 1;
bool neg = false;
if (md <= 1) return {1, (long)f};
if (f < 0) {
neg = true;
f = -f;
}
while (f != Math.floor(f)) {
n <<= 1;
f *= 2;
}
d = (long)f;
for (int i = 0; i < 64; i++) {
a = (n != 0) ? d / n : 0;
if (i != 0 && a == 0) break;
x = d; d = n; n = x %n;
x = a;
if (k[1] * a + k[0] >= md) {
x = (md - k[0]) / k[1];
if (x * 2 >= a || k[1] >= md)
i = 65;
else
break;
}
h[2] = x * h[1] + h[0]; h[0] = h[1]; h[1] = h[2];
k[2] = x * k[1] + k[0]; k[0] = k[1]; k[1] = k[2];
}
return {k[1], neg ? -h[1] : h[1]};
}
void main() {
double f;
print("f = %16.14f\n", f = 1.0/7);
for (int i = 1; i < 20000000; i *= 16) {
print("denom <= %11d: ", i);
var r = rat_approx(f, i);
print("%11ld/%ld\n", r.n, r.d);
}
print("f = %16.14f\n", f = Math.atan2(1,1) * 4);
for (int i = 1; i < 20000000; i *= 16) {
print("denom <= %11d: ", i);
var r = rat_approx(f, i);
print("%11ld/%ld\n", r.n, r.d);
}
} |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Elixir | Elixir | src = "Hello"
dst = src |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Emacs_Lisp | Emacs Lisp | (let* ((str1 "hi")
(str1-ref str1)
(str2 (copy-sequence str1)))
(eq str1 str1-ref) ;=> t
(eq str1 str2) ;=> nil
(equal str1 str1-ref) ;=> t
(equal str1 str2)) ;=> t |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #C.2B.2B | C++ |
#include <iostream>
#include <vector>
using entry = std::pair<int, const char*>;
void print(const std::vector<entry>& entries, std::ostream& out = std::cout)
{
bool first = true;
for(const auto& e: entries) {
if(!first) out << ", ";
first = false;
out << e.first << " " << e.second;
}
out << '\n';
}
std::vector<entry> convert(int seconds)
{
static const entry time_table[] = {
{7*24*60*60, "wk"}, {24*60*60, "d"}, {60*60, "hr"}, {60, "min"}, {1, "sec"}
};
std::vector<entry> result;
for(const auto& e: time_table) {
int time = seconds / e.first;
if(time != 0) result.emplace_back(time, e.second);
seconds %= e.first;
}
return result;
}
int main()
{
std::cout << " 7259 sec is "; print(convert( 7259));
std::cout << " 86400 sec is "; print(convert( 86400));
std::cout << "6000000 sec is "; print(convert(6000000));
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Haskell | Haskell | class Eatable a where
eat :: a -> String |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Icon_and_Unicon | Icon and Unicon | import Utils # From the UniLib package to get the Class class.
class Eatable:Class()
end
class Fish:Eatable(name)
method eat(); write("Eating "+name); end
end
class Rock:Class(name)
method eat(); write("Eating "+name); end
end
class FoodBox(A)
initially
every item := !A do if "Eatable" == item.Type() then next else bad := "yes"
return /bad
end
procedure main()
if FoodBox([Fish("salmon")]) then write("Edible") else write("Inedible")
if FoodBox([Rock("granite")]) then write("Edible") else write("Inedible")
end |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #J | J | coclass'Connoisseur'
isEdible=:3 :0
0<nc<'eat__y'
)
coclass'FoodBox'
create=:3 :0
collection=: 0#y
)
add=:3 :0"0
'inedible' assert isEdible_Connoisseur_ y
collection=: collection, y
EMPTY
) |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #FreeBASIC | FreeBASIC | #define UPPER 1000000
#include"isprime.bas"
dim as uinteger champ = 0, record = 0, streak, i, j, n
'first generate all the primes below UPPER
redim as uinteger prime(1 to 2)
prime(1) = 2 : prime(2) = 3
for i = 5 to UPPER step 2
if isprime(i) then
redim preserve prime(1 to ubound(prime) + 1)
prime(ubound(prime)) = i
end if
next i
n = ubound(prime)
'now look for the longest streak of ascending primes
for i = 2 to n-1
j = i + 1
streak = 1
while j<=n andalso prime(j)-prime(j-1) > prime(j-1)-prime(j-2)
streak += 1
j+=1
wend
if streak > record then
champ = i-1
record = streak
end if
next i
print "The longest sequence of ascending primes (with their difference from the last one) is:"
for i = champ+1 to champ+record
print prime(i-1);" (";prime(i)-prime(i-1);") ";
next i
print prime(i-1) : print
'now for the descending ones
record = 0 : champ = 0
for i = 2 to n-1
j = i + 1
streak = 1
while j<=n andalso prime(j)-prime(j-1) < prime(j-1)-prime(j-2) 'identical to above, but for the inequality sign
streak += 1
j+=1
wend
if streak > record then
champ = i-1
record = streak
end if
next i
print "The longest sequence of descending primes (with their difference from the last one) is:"
for i = champ+1 to champ+record
print prime(i-1);" (";prime(i)-prime(i-1);") ";
next i
print prime(i-1) |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Go | Go | package main
import (
"fmt"
"rcu"
)
const LIMIT = 999999
var primes = rcu.Primes(LIMIT)
func longestSeq(dir string) {
pd := 0
longSeqs := [][]int{{2}}
currSeq := []int{2}
for i := 1; i < len(primes); i++ {
d := primes[i] - primes[i-1]
if (dir == "ascending" && d <= pd) || (dir == "descending" && d >= pd) {
if len(currSeq) > len(longSeqs[0]) {
longSeqs = [][]int{currSeq}
} else if len(currSeq) == len(longSeqs[0]) {
longSeqs = append(longSeqs, currSeq)
}
currSeq = []int{primes[i-1], primes[i]}
} else {
currSeq = append(currSeq, primes[i])
}
pd = d
}
if len(currSeq) > len(longSeqs[0]) {
longSeqs = [][]int{currSeq}
} else if len(currSeq) == len(longSeqs[0]) {
longSeqs = append(longSeqs, currSeq)
}
fmt.Println("Longest run(s) of primes with", dir, "differences is", len(longSeqs[0]), ":")
for _, ls := range longSeqs {
var diffs []int
for i := 1; i < len(ls); i++ {
diffs = append(diffs, ls[i]-ls[i-1])
}
for i := 0; i < len(ls)-1; i++ {
fmt.Print(ls[i], " (", diffs[i], ") ")
}
fmt.Println(ls[len(ls)-1])
}
fmt.Println()
}
func main() {
fmt.Println("For primes < 1 million:\n")
for _, dir := range []string{"ascending", "descending"} {
longestSeq(dir)
}
} |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #C | C | /* calculate approximations for continued fractions */
#include <stdio.h>
/* kind of function that returns a series of coefficients */
typedef double (*coeff_func)(unsigned n);
/* calculates the specified number of expansions of the continued fraction
* described by the coefficient series f_a and f_b */
double calc(coeff_func f_a, coeff_func f_b, unsigned expansions)
{
double a, b, r;
a = b = r = 0.0;
unsigned i;
for (i = expansions; i > 0; i--) {
a = f_a(i);
b = f_b(i);
r = b / (a + r);
}
a = f_a(0);
return a + r;
}
/* series for sqrt(2) */
double sqrt2_a(unsigned n)
{
return n ? 2.0 : 1.0;
}
double sqrt2_b(unsigned n)
{
return 1.0;
}
/* series for the napier constant */
double napier_a(unsigned n)
{
return n ? n : 2.0;
}
double napier_b(unsigned n)
{
return n > 1.0 ? n - 1.0 : 1.0;
}
/* series for pi */
double pi_a(unsigned n)
{
return n ? 6.0 : 3.0;
}
double pi_b(unsigned n)
{
double c = 2.0 * n - 1.0;
return c * c;
}
int main(void)
{
double sqrt2, napier, pi;
sqrt2 = calc(sqrt2_a, sqrt2_b, 1000);
napier = calc(napier_a, napier_b, 1000);
pi = calc(pi_a, pi_b, 1000);
printf("%12.10g\n%12.10g\n%12.10g\n", sqrt2, napier, pi);
return 0;
} |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #VBA | VBA | Function Real2Rational(r As Double, bound As Long) As String
If r = 0 Then
Real2Rational = "0/1"
ElseIf r < 0 Then
Result = Real2Rational(-r, bound)
Real2Rational = "-" & Result
Else
best = 1
bestError = 1E+99
For i = 1 To bound + 1
currentError = Abs(i * r - Round(i * r))
If currentError < bestError Then
best = i
bestError = currentError
If bestError < 1 / bound Then GoTo SkipLoop
End If
Next i
SkipLoop:
Real2Rational = Round(best * r) & "/" & best
End If
End Function
Sub TestReal2Rational()
Debug.Print "0.75" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(0.75, CLng(Order));
Next i
Debug.Print
Debug.Print "0.518518" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(0.518518, CLng(Order));
Next i
Debug.Print
Debug.Print "0.9054054" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(0.9054054, CLng(Order));
Next i
Debug.Print
Debug.Print "0.142857143" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(0.142857143, CLng(Order));
Next i
Debug.Print
Debug.Print "3.141592654" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(3.141592654, CLng(Order));
Next i
Debug.Print
Debug.Print "2.718281828" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(2.718281828, CLng(Order));
Next i
Debug.Print
Debug.Print "-0.423310825" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(-0.423310825, CLng(Order));
Next i
Debug.Print
Debug.Print "31.415926536" & ":";
For i = 0 To 5
Order = CDbl(10) ^ CDbl(i)
Debug.Print " " & Real2Rational(31.415926536, CLng(Order));
Next i
End Sub
|
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Erlang | Erlang | Src = "Hello".
Dst = Src. |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Euphoria | Euphoria | sequence first = "ABC"
sequence newOne = first |
http://rosettacode.org/wiki/Convex_hull | Convex hull | Find the points which form a convex hull from a set of arbitrary two dimensional points.
For example, given the points (16,3), (12,17), (0,6), (-4,-6), (16,6), (16,-7), (16,-3), (17,-4), (5,19), (19,-8), (3,16), (12,13), (3,-4), (17,5), (-3,15), (-3,-9), (0,11), (-9,-3), (-4,-2) and (12,10) the convex hull would be (-9,-3), (-3,-9), (19,-8), (17,5), (12,17), (5,19) and (-3,15).
See also
Convex Hull (youtube)
http://www.geeksforgeeks.org/convex-hull-set-2-graham-scan/
| #11l | 11l | F orientation(p, q, r)
V val = (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y)
I val == 0
R 0
R I val > 0 {1} E 2
F calculateConvexHull(points)
[(Int, Int)] result
I points.len < 3
R points
V indexMinX = 0
L(p) points
V i = L.index
I p.x < points[indexMinX].x
indexMinX = i
V p = indexMinX
V q = 0
L
result.append(points[p])
q = (p + 1) % points.len
L(i) 0 .< points.len
I orientation(points[p], points[i], points[q]) == 2
q = i
p = q
I p == indexMinX
L.break
R result
V points = [(16, 3),
(12, 17),
(0, 6),
(-4, -6),
(16, 6),
(16, -7),
(17, -4),
(5, 19),
(19, -8),
(3, 16),
(12, 13),
(3, -4),
(17, 5),
(-3, 15),
(-3, -9),
(0, 11),
(-9, -3),
(-4, -2),
(12, 10)]
V hull = calculateConvexHull(points)
L(i) hull
print(i) |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #Clojure | Clojure | (require '[clojure.string :as string])
(def seconds-in-minute 60)
(def seconds-in-hour (* 60 seconds-in-minute))
(def seconds-in-day (* 24 seconds-in-hour))
(def seconds-in-week (* 7 seconds-in-day))
(defn seconds->duration [seconds]
(let [weeks ((juxt quot rem) seconds seconds-in-week)
wk (first weeks)
days ((juxt quot rem) (last weeks) seconds-in-day)
d (first days)
hours ((juxt quot rem) (last days) seconds-in-hour)
hr (first hours)
min (quot (last hours) seconds-in-minute)
sec (rem (last hours) seconds-in-minute)]
(string/join ", "
(filter #(not (string/blank? %))
(conj []
(when (> wk 0) (str wk " wk"))
(when (> d 0) (str d " d"))
(when (> hr 0) (str hr " hr"))
(when (> min 0) (str min " min"))
(when (> sec 0) (str sec " sec")))))))
(seconds->duration 7259)
(seconds->duration 86400)
(seconds->duration 6000000) |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Java | Java | interface Eatable
{
void eat();
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Julia | Julia | abstract type Edible end
eat(::Edible) = "Yum!"
mutable struct FoodBox{T<:Edible}
food::Vector{T}
end
struct Carrot <: Edible
variety::AbstractString
end
struct Brick
volume::Float64
end
c = Carrot("Baby")
b = Brick(125.0)
eat(c)
eat(b) |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Kotlin | Kotlin | // version 1.0.6
interface Eatable {
fun eat()
}
class Cheese(val name: String) : Eatable {
override fun eat() {
println("Eating $name")
}
override fun toString() = name
}
class Meat(val name: String) : Eatable {
override fun eat() {
println("Eating $name")
}
override fun toString() = name
}
class FoodBox<T: Eatable> {
private val foodList = mutableListOf<T>()
fun add(food: T) {
foodList.add(food)
}
override fun toString() = foodList.toString()
}
fun main(args: Array<String>) {
val cheddar = Cheese("cheddar")
val feta = Cheese("feta")
val cheeseBox = FoodBox<Cheese>()
cheeseBox.add(cheddar)
cheeseBox.add(feta)
println("CheeseBox contains : $cheeseBox")
val beef = Meat("beef")
val ham = Meat("ham")
val meatBox = FoodBox<Meat>()
meatBox.add(beef)
meatBox.add(ham)
println("MeatBox contains : $meatBox")
cheddar.eat()
beef.eat()
println("Full now!")
} |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Haskell | Haskell | import Data.Numbers.Primes (primes)
-- generates consecutive subsequences defined by given equivalence relation
consecutives equiv = filter ((> 1) . length) . go []
where
go r [] = [r]
go [] (h : t) = go [h] t
go (y : ys) (h : t)
| y `equiv` h = go (h : y : ys) t
| otherwise = (y : ys) : go [h] t
-- finds maximal values in a list and returns the first one
maximumBy g (h : t) = foldr f h t
where
f r x = if g r < g x then x else r
-- the task implementation
task ord n = reverse $ p + s : p : (fst <$> rest)
where
(p, s) : rest =
maximumBy length $
consecutives (\(_, a) (_, b) -> a `ord` b) $
differences $
takeWhile (< n) primes
differences l = zip l $ zipWith (-) (tail l) l |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #jq | jq | # For streams of strings or of arrays or of numbers:
def add(s): reduce s as $x (null; .+$x);
# Primes less than . // infinite
def primes:
(. // infinite) as $n
| if $n < 3 then empty
else 2, (range(3; $n) | select(is_prime))
end;
|
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #C.23 | C# | using System;
using System.Collections.Generic;
namespace ContinuedFraction {
class Program {
static double Calc(Func<int, int[]> f, int n) {
double temp = 0.0;
for (int ni = n; ni >= 1; ni--) {
int[] p = f(ni);
temp = p[1] / (p[0] + temp);
}
return f(0)[0] + temp;
}
static void Main(string[] args) {
List<Func<int, int[]>> fList = new List<Func<int, int[]>>();
fList.Add(n => new int[] { n > 0 ? 2 : 1, 1 });
fList.Add(n => new int[] { n > 0 ? n : 2, n > 1 ? (n - 1) : 1 });
fList.Add(n => new int[] { n > 0 ? 6 : 3, (int) Math.Pow(2 * n - 1, 2) });
foreach (var f in fList) {
Console.WriteLine(Calc(f, 200));
}
}
}
} |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #Wren | Wren | import "/rat" for Rat
import "/fmt" for Fmt
var tests = [0.9054054, 0.518518, 0.75]
for (test in tests) {
var r = Rat.fromFloat(test)
System.print("%(Fmt.s(-9, test)) -> %(r)")
} |
http://rosettacode.org/wiki/Convert_decimal_number_to_rational | Convert decimal number to rational | This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.
The task is to write a program to transform a decimal number into a fraction in lowest terms.
It is not always possible to do this exactly. For instance, while rational numbers can be converted to decimal representation, some of them need an infinite number of digits to be represented exactly in decimal form. Namely, repeating decimals such as 1/3 = 0.333...
Because of this, the following fractions cannot be obtained (reliably) unless the language has some way of representing repeating decimals:
67 / 74 = 0.9(054) = 0.9054054...
14 / 27 = 0.(518) = 0.518518...
Acceptable output:
0.9054054 → 4527027 / 5000000
0.518518 → 259259 / 500000
Finite decimals are of course no problem:
0.75 → 3 / 4
| #zkl | zkl | fcn real2Rational(r,bound){
if (r == 0.0) return(0,1);
if (r < 0.0){
result := real2Rational(-r, bound);
return(-result[0],result[1]);
} else {
best,bestError := 1,(1.0).MAX;
foreach i in ([1 .. bound + 1]){
error := (r*i - (r*i).round()).abs();
if (error < bestError) best,bestError = i,error;
}
return((r*best).round().toInt(),best);
}
} |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #F.23 | F# | let str = "hello"
let additionalReference = str
let deepCopy = System.String.Copy( str )
printfn "%b" <| System.Object.ReferenceEquals( str, additionalReference ) // prints true
printfn "%b" <| System.Object.ReferenceEquals( str, deepCopy ) // prints false |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Factor | Factor | "This is a mutable string." dup ! reference
"Let's make a deal!" dup clone ! copy
"New" " string" append . ! new string
"New string" |
http://rosettacode.org/wiki/Convex_hull | Convex hull | Find the points which form a convex hull from a set of arbitrary two dimensional points.
For example, given the points (16,3), (12,17), (0,6), (-4,-6), (16,6), (16,-7), (16,-3), (17,-4), (5,19), (19,-8), (3,16), (12,13), (3,-4), (17,5), (-3,15), (-3,-9), (0,11), (-9,-3), (-4,-2) and (12,10) the convex hull would be (-9,-3), (-3,-9), (19,-8), (17,5), (12,17), (5,19) and (-3,15).
See also
Convex Hull (youtube)
http://www.geeksforgeeks.org/convex-hull-set-2-graham-scan/
| #Action.21 | Action! | DEFINE POINTSIZE="4"
TYPE PointI=[INT x,y]
CARD FUNC GetAddr(INT ARRAY points BYTE index)
RETURN (points+POINTSIZE*index)
BYTE FUNC GetMinXIndex(INT ARRAY points BYTE pLen)
PointI POINTER p
BYTE i,index
INT minX
p=GetAddr(points,0)
minX=p.x
index=0
FOR i=1 TO pLen-1
DO
p=GetAddr(points,i)
IF p.x<minX THEN
minX=p.x
index=i
FI
OD
RETURN (index)
BYTE FUNC Orientation(PointI POINTER p,q,r)
INT v
v=(q.y-p.y)*(r.x-q.x)
v==-(q.x-p.x)*(r.y-q.y)
IF v=0 THEN
RETURN (0)
ELSEIF v>0 THEN
RETURN (1)
FI
RETURN (2)
PROC ConvexHull(INT ARRAY points BYTE pLen
INT ARRAY res BYTE POINTER resLen)
PointI POINTER pSrc,pDst,p1,p2,p3
BYTE minIndex,i,p,q
IF pLen<3 THEN
resLen^=pLen
MoveBlock(res,points,pLen*POINTSIZE)
RETURN
FI
resLen^=0
minIndex=GetMinXIndex(points,pLen)
p=minIndex q=0
DO
pSrc=GetAddr(points,p)
pDst=GetAddr(res,resLen^)
pDst.x=pSrc.x
pDst.y=pSrc.y
resLen^==+1
q=(p+1) MOD pLen
FOR i=0 TO pLen-1
DO
p1=GetAddr(points,p)
p2=GetAddr(points,i)
p3=GetAddr(points,q)
IF Orientation(p1,p2,p3)=2 THEN
q=i
FI
OD
p=q
UNTIL p=minIndex
OD
RETURN
PROC PrintPoints(INT ARRAY points BYTE len)
PointI POINTER p
BYTE i
FOR i=0 TO len-1
DO
p=GetAddr(points,i)
PrintF("(%I,%I) ",p.x,p.y)
OD
RETURN
PROC Main()
INT ARRAY points=[
16 3 12 17 0 6 65532 65530
16 6 16 65529 17 65532 5 19
19 65528 3 16 12 13 3 65532
17 5 65533 15 65533 65527
0 11 65527 65533 65532 65534
12 10]
INT ARRAY result(38)
BYTE pLen=[19],rlen
ConvexHull(points,pLen,result,@rlen)
PrintE("Points:")
PrintPoints(points,pLen)
PutE() PutE()
PrintE("Convex hull:")
PrintPoints(result,rLen)
RETURN |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #CLU | CLU | duration = proc (s: int) returns (string)
own units: array[string] := array[string]$["wk","d","hr","min","sec"]
own sizes: array[int] := array[int]$[2:7,24,60,60]
d: string := ""
r: int
for i: int in int$from_to_by(5,1,-1) do
begin
r := s // sizes[i]
s := s / sizes[i]
end except when bounds:
r := s
end
if r ~= 0 then
d := ", " || int$unparse(r) || " " || units[i] || d
end
end
return(string$rest(d,3))
end duration
start_up = proc ()
po: stream := stream$primary_output()
tests: array[int] := array[int]$[7259,86400,6000000]
for test: int in array[int]$elements(tests) do
stream$putl(po, int$unparse(test) || " => " || duration(test))
end
end start_up |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #COBOL | COBOL | identification division.
program-id. fmt-dura.
data division.
working-storage section.
1 input-seconds pic 9(8).
1 formatted-duration pic x(30) global.
1 fractions.
2 weeks pic z(3)9.
2 days pic z(3)9.
2 hours pic z(3)9.
2 minutes pic z(3)9.
2 seconds pic z(3)9.
1 .
2 weeks-str pic x(4) value "wk".
2 days-str pic x(4) value "d".
2 hours-str pic x(4) value "hr".
2 minutes-str pic x(4) value "min".
2 seconds-str pic x(4) value "sec".
1 work binary global.
2 str-pos pic 9(4).
2 chars-transferred pic 9(4).
procedure division.
begin.
display "Enter duration (seconds): " no advancing
accept input-seconds
divide input-seconds by 60 giving input-seconds
remainder seconds
divide input-seconds by 60 giving input-seconds
remainder minutes
divide input-seconds by 24 giving input-seconds
remainder hours
divide input-seconds by 7 giving weeks
remainder days
move 1 to str-pos
call "fmt" using weeks weeks-str
call "fmt" using days days-str
call "fmt" using hours hours-str
call "fmt" using minutes minutes-str
call "fmt" using seconds seconds-str
display formatted-duration
stop run
.
identification division.
program-id. fmt.
data division.
working-storage section.
77 nothing pic x.
linkage section.
1 formatted-value pic x(4).
1 duration-size pic x(4).
procedure division using formatted-value duration-size.
begin.
if function numval (formatted-value) not = 0
perform insert-comma-space
unstring formatted-value delimited all space
into nothing formatted-duration (str-pos:)
count chars-transferred
add chars-transferred to str-pos
string space delimited size
duration-size delimited space
into formatted-duration pointer str-pos
end-if
exit program
.
insert-comma-space.
if str-pos > 1
move ", " to formatted-duration (str-pos:)
add 2 to str-pos
end-if
.
end program fmt.
end program fmt-dura. |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Morfa | Morfa | import morfa.type.traits;
template < T >
alias IsEdible = HasMember< T, "eat" >;
template < T >
if (IsEdible< T >)
struct FoodBox
{
var food: T[];
}
struct Carrot
{
func eat(): void {}
}
struct Car {}
func main(): void
{
var carrotBox: FoodBox< Carrot >; // OK
carrotBox.food ~= Carrot(); // Adds a carrot
// var carBox: FoodBox< Car >; // Not allowed
static assert( not trait(compiles, func() { var carBox: FoodBox< Car >; } ));
} |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Nemerle | Nemerle | using System.Collections.Generic;
interface IEatable
{
Eat() : void;
}
class FoodBox[T] : IEnumerable[T]
where T : IEatable
{
private _foods : list[T] = [];
public this() {}
public this(items : IEnumerable[T])
{
this._foods = $[food | food in items];
}
public Add(food : T) : FoodBox[T]
{
FoodBox(food::_foods);
}
public GetEnumerator() : IEnumerator[T]
{
_foods.GetEnumerator();
}
}
class Apple : IEatable
{
public this() {}
public Eat() : void
{
System.Console.WriteLine("nom..nom..nom");
}
}
mutable appleBox = FoodBox();
repeat(3) {
appleBox = appleBox.Add(Apple());
}
foreach (apple in appleBox) apple.Eat(); |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Nim | Nim | type
Eatable = concept e
eat(e)
FoodBox[e: Eatable] = seq[e]
Food = object
name: string
count: int
proc eat(x: int) = echo "Eating the int: ", x
proc eat(x: Food) = echo "Eating ", x.count, " ", x.name, "s"
var ints = FoodBox[int](@[1,2,3,4,5])
var fs = FoodBox[Food](@[])
fs.add Food(name: "Hamburger", count: 3)
fs.add Food(name: "Cheeseburger", count: 5)
for f in fs:
eat(f) |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Objeck | Objeck | use Collection.Generic;
interface Eatable {
method : virtual : Eat() ~ Nil;
}
class FoodBox<T : Eatable> {
food : List<T>;
}
class Plum implements Eatable {
method : Eat() ~ Nil {
"Yummy Plum!"->PrintLine();
}
}
class Genericity {
function : Main(args : String[]) ~ Nil {
plums : FoodBox<Plum>;
}
} |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Julia | Julia | using Primes
function primediffseqs(maxnum = 1_000_000)
mprimes = primes(maxnum)
diffs = map(p -> mprimes[p[1] + 1] - p[2], enumerate(@view mprimes[begin:end-1]))
incstart, decstart, bestinclength, bestdeclength = 1, 1, 0, 0
for i in 1:length(diffs)-1
foundinc, founddec = false, false
for j in i+1:length(diffs)
if !foundinc && diffs[j] <= diffs[j - 1]
if (runlength = j - i) > bestinclength
bestinclength, incstart = runlength, i
end
foundinc = true
end
if !founddec && diffs[j] >= diffs[j - 1]
if (runlength = j - i) > bestdeclength
bestdeclength, decstart = runlength, i
end
founddec = true
end
foundinc && founddec && break
end
end
println("Ascending: ", mprimes[incstart:incstart+bestinclength], " Diffs: ", diffs[incstart:incstart+bestinclength-1])
println("Descending: ", mprimes[decstart:decstart+bestdeclength], " Diffs: ", diffs[decstart:decstart+bestdeclength-1])
end
primediffseqs()
|
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Lua | Lua | function findcps(primelist, fcmp)
local currlist = {primelist[1]}
local longlist, prevdiff = currlist, 0
for i = 2, #primelist do
local diff = primelist[i] - primelist[i-1]
if fcmp(diff, prevdiff) then
currlist[#currlist+1] = primelist[i]
if #currlist > #longlist then
longlist = currlist
end
else
currlist = {primelist[i-1], primelist[i]}
end
prevdiff = diff
end
return longlist
end
primegen:generate(nil, 1000000)
cplist = findcps(primegen.primelist, function(a,b) return a>b end)
print("ASC ("..#cplist.."): ["..table.concat(cplist, " ").."]")
cplist = findcps(primegen.primelist, function(a,b) return a<b end)
print("DESC ("..#cplist.."): ["..table.concat(cplist, " ").."]") |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #C.2B.2B | C++ | #include <iomanip>
#include <iostream>
#include <tuple>
typedef std::tuple<double,double> coeff_t; // coefficients type
typedef coeff_t (*func_t)(int); // callback function type
double calc(func_t func, int n)
{
double a, b, temp = 0;
for (; n > 0; --n) {
std::tie(a, b) = func(n);
temp = b / (a + temp);
}
std::tie(a, b) = func(0);
return a + temp;
}
coeff_t sqrt2(int n)
{
return coeff_t(n > 0 ? 2 : 1, 1);
}
coeff_t napier(int n)
{
return coeff_t(n > 0 ? n : 2, n > 1 ? n - 1 : 1);
}
coeff_t pi(int n)
{
return coeff_t(n > 0 ? 6 : 3, (2 * n - 1) * (2 * n - 1));
}
int main()
{
std::streamsize old_prec = std::cout.precision(15); // set output digits
std::cout
<< calc(sqrt2, 20) << '\n'
<< calc(napier, 15) << '\n'
<< calc(pi, 10000) << '\n'
<< std::setprecision(old_prec); // reset precision
} |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Forth | Forth | \ Allocate two string buffers
create stringa 256 allot
create stringb 256 allot
\ Copy a constant string into a string buffer
s" Hello" stringa place
\ Copy the contents of one string buffer into another
stringa count stringb place |
http://rosettacode.org/wiki/Constrained_random_points_on_a_circle | Constrained random points on a circle | Task
Generate 100 <x,y> coordinate pairs such that x and y are integers sampled from the uniform distribution with the condition that
10
≤
x
2
+
y
2
≤
15
{\displaystyle 10\leq {\sqrt {x^{2}+y^{2}}}\leq 15}
.
Then display/plot them. The outcome should be a "fuzzy" circle. The actual number of points plotted may be less than 100, given that some pairs may be generated more than once.
There are several possible approaches to accomplish this. Here are two possible algorithms.
1) Generate random pairs of integers and filter out those that don't satisfy this condition:
10
≤
x
2
+
y
2
≤
15
{\displaystyle 10\leq {\sqrt {x^{2}+y^{2}}}\leq 15}
.
2) Precalculate the set of all possible points (there are 404 of them) and select randomly from this set.
| #11l | 11l | F print_circle(lo, hi, ndots)
V canvas = [[0B] * (2*hi+1)] * (2*hi+1)
V i = 0
L i < ndots
V x = random:(-hi..hi)
V y = random:(-hi..hi)
I x^2 + y^2 C lo^2 .. hi^2
canvas[x + hi][y + hi] = 1B
i++
L(i) 0 .. 2*hi
print(canvas[i].map(j -> I j {‘♦ ’} E ‘ ’).join(‘’))
print_circle(10, 15, 100) |
http://rosettacode.org/wiki/Convex_hull | Convex hull | Find the points which form a convex hull from a set of arbitrary two dimensional points.
For example, given the points (16,3), (12,17), (0,6), (-4,-6), (16,6), (16,-7), (16,-3), (17,-4), (5,19), (19,-8), (3,16), (12,13), (3,-4), (17,5), (-3,15), (-3,-9), (0,11), (-9,-3), (-4,-2) and (12,10) the convex hull would be (-9,-3), (-3,-9), (19,-8), (17,5), (12,17), (5,19) and (-3,15).
See also
Convex Hull (youtube)
http://www.geeksforgeeks.org/convex-hull-set-2-graham-scan/
| #Ada | Ada | with Ada.Text_IO;
with Ada.Containers.Vectors;
procedure Convex_Hull is
type Point is record
X, Y : Integer;
end record;
package Point_Vectors is
new Ada.Containers.Vectors (Index_Type => Positive,
Element_Type => Point);
use Point_Vectors;
function Find_Convex_Hull (Vec : in Vector) return Vector is
function Counter_Clock_Wise (A, B, C : in Point) return Boolean is
((B.X - A.X) * (C.Y - A.Y) > (B.Y - A.Y) * (C.X - A.X));
function Less_Than (Left, Right : Point) return Boolean is
(Left.X < Right.X);
package Sorter is
new Point_Vectors.Generic_Sorting (Less_Than);
Sorted : Vector := Vec;
Result : Vector := Empty_vector;
use type Ada.Containers.Count_Type;
begin
if Vec = Empty_Vector then
return Empty_Vector;
end if;
Sorter.Sort (Sorted);
-- Lower hull
for Index in Sorted.First_Index .. Sorted.Last_Index loop
while
Result.Length >= 2 and then
not Counter_Clock_Wise (Result (Result.Last_Index - 1),
Result (Result.Last_Index),
Sorted (Index))
loop
Result.Delete_Last;
end loop;
Result.Append (Sorted (Index));
end loop;
-- Upper hull
declare
T : constant Ada.Containers.Count_Type := Result.Length + 1;
begin
for Index in reverse Sorted.First_Index .. Sorted.Last_Index loop
while
Result.Length >= T and then
not Counter_Clock_Wise (Result (Result.Last_Index - 1),
Result (Result.Last_Index),
Sorted (Index))
loop
Result.Delete_Last;
end loop;
Result.Append (Sorted (Index));
end loop;
end;
Result.Delete_Last;
return Result;
end Find_Convex_Hull;
procedure Show (Vec : in Vector) is
use Ada.Text_IO;
begin
Put ("[ ");
for Point of Vec loop
Put ("(" & Point.X'Image & "," & Point.Y'Image & ")");
end loop;
Put (" ]");
end Show;
Vec : constant Vector :=
(16, 3) & (12,17) & ( 0, 6) & (-4,-6) & (16, 6) &
(16,-7) & (16,-3) & (17,-4) & ( 5,19) & (19,-8) &
( 3,16) & (12,13) & ( 3,-4) & (17, 5) & (-3,15) &
(-3,-9) & ( 0,11) & (-9,-3) & (-4,-2) & (12,10);
begin
Show (Find_Convex_Hull (Vec));
Ada.Text_IO.New_Line;
end Convex_Hull; |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #Common_Lisp | Common Lisp | (defconstant +seconds-in-minute* 60)
(defconstant +seconds-in-hour* (* 60 +seconds-in-minute*))
(defconstant +seconds-in-day* (* 24 +seconds-in-hour*))
(defconstant +seconds-in-week* (* 7 +seconds-in-day*))
(defun seconds->duration (seconds)
(multiple-value-bind (weeks wk-remainder) (floor seconds +seconds-in-week*)
(multiple-value-bind (days d-remainder) (floor wk-remainder +seconds-in-day*)
(multiple-value-bind (hours hr-remainder) (floor d-remainder +seconds-in-hour*)
(multiple-value-bind (minutes secs) (floor hr-remainder +seconds-in-minute*)
(let ((chunks nil))
(unless (zerop secs) (push (format nil "~D sec" secs) chunks))
(unless (zerop minutes) (push (format nil "~D min" minutes) chunks))
(unless (zerop hours) (push (format nil "~D hr" hours) chunks))
(unless (zerop days) (push (format nil "~D d" days) chunks))
(unless (zerop weeks) (push (format nil "~D wk" weeks) chunks))
(format t "~{~A~^, ~}~%" chunks)))))))
(seconds->duration 7259)
(seconds->duration 86400)
(seconds->duration 6000000)
|
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Objective-C | Objective-C | @protocol Eatable
- (void)eat;
@end |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #OCaml | OCaml | module type Eatable = sig
type t
val eat : t -> unit
end |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #ooRexx | ooRexx | call dinnerTime "yogurt"
call dinnerTime .pizza~new
call dinnerTime .broccoli~new
-- a mixin class that defines the interface for being "food", and
-- thus expected to implement an "eat" method
::class food mixinclass object
::method eat abstract
::class pizza subclass food
::method eat
Say "mmmmmmmm, pizza".
-- mixin classes can also be used for multiple inheritance
::class broccoli inherit food
::method eat
Say "ugh, do I have to?".
::routine dinnerTime
use arg dish
-- ooRexx arguments are typeless, so tests for constrained
-- types must be peformed at run time. The isA method will
-- check if an object is of the required type
if \dish~isA(.food) then do
say "I can't eat that!"
return
end
else dish~eat |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #OxygenBasic | OxygenBasic |
macro Gluttony(vartype, capacity, foodlist)
'==========================================
typedef vartype physical
enum food foodlist
type ActualFood
sys name
physical size
physical quantity
end type
Class foodbox
'============
has ActualFood Item[capacity]
sys max
method put(sys f, physical s,q)
max++
Item[max]<=f,s,q
end method
method GetNext(ActualFood *Stuff)
if max then
copy @stuff,@Item[max], sizeof Item
max--
end if
end method
end class
Class Gourmand
'=============
physical WeightGain, SleepTime
method eats(ActualFood *stuff)
WeightGain+=stuff.size*stuff.quantity*0.75
stuff.size=0
stuff.quantity=0
end method
end class
end macro
'IMPLEMENTATION
'==============
Gluttony (
double,100,{
oyster,trout,bloater,
chocolate,truffles,
cheesecake,cream,pudding,pie
})
% small 1
% medium 2
% large 3
% huge 7
% none 0
% single 1
% few 3
% several 7
% many 12
'INSTANCE
'========
FoodBox Hamper
Gourmand MrG
'TEST
'====
Hamper.put food.pudding,large,several
Hamper.put food.pie,huge,few
ActualFood Course
Hamper.GetNext Course
MrG.eats Course
print MrG.WeightGain 'result 15.75
|
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | prime = Prime[Range[PrimePi[10^6]]];
s = Split[Differences[prime], Less];
max = Max[Length /@ s];
diffs = Select[s, Length/*EqualTo[max]];
seqs = SequencePosition[Flatten[s], #, 1][[1]] & /@ diffs;
Take[prime, # + {0, 1}] & /@ seqs
s = Split[Differences[prime], Greater];
max = Max[Length /@ s];
diffs = Select[s, Length/*EqualTo[max]];
seqs = SequencePosition[Flatten[s], #, 1][[1]] & /@ diffs;
Take[prime, # + {0, 1}] & /@ seqs |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Nim | Nim | import math, strformat, sugar
const N = 1_000_000
####################################################################################################
# Erathostenes sieve.
var composite: array[2..N, bool] # Initialized to false i.e. prime.
for n in 2..int(sqrt(float(N))):
if not composite[n]:
for k in countup(n * n, N, n):
composite[k] = true
let primes = collect(newSeq):
for n in 2..N:
if not composite[n]: n
####################################################################################################
# Longest sequences.
type Order {.pure.} = enum Ascending, Descending
proc longestSeq(order: Order): seq[int] =
## Return the longest sequence for the given order.
let ascending = order == Ascending
var
currseq: seq[int]
prevPrime = 2
diff = if ascending: 0 else: N
for prime in primes:
let nextDiff = prime - prevPrime
if nextDiff != diff and nextDiff > diff == ascending:
currseq.add prime
else:
if currseq.len > result.len:
result = move(currseq)
currseq = @[prevPrime, prime]
diff = nextDiff
prevPrime = prime
if currseq.len > result.len:
result = move(currseq)
proc `$`(list: seq[int]): string =
## Return the representation of a list of primes with interleaved differences.
var prevPrime: int
for i, prime in list:
if i != 0: result.add &" ({prime - prevPrime}) "
result.addInt prime
prevPrime = prime
echo "For primes < 1000000.\n"
echo "First longest sequence of consecutive primes with ascending differences:"
echo longestSeq(Ascending)
echo()
echo "First longest sequence of consecutive primes with descending differences:"
echo longestSeq(Descending) |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Pari.2FGP | Pari/GP | showPrecPrimes(p, n)=
{
my(v=vector(n));
v[n]=p;
forstep(i=n-1,1,-1,
v[i]=precprime(v[i+1]-1)
);
for(i=1,n, print1(v[i]" "));
}
list(lim)=
{
my(p=3,asc,dec,ar,dr,arAt=3,drAt=3,last=2);
forprime(q=5,lim,
my(g=q-p);
if(g<last,
asc=0;
if(desc++>dr,
dr=desc;
drAt=q
)
,g>last,
desc=0;
if(asc++>ar,
ar=asc;
arAt=q
)
,
asc=desc=0
);
p=q;
last=g
);
print("Descending differences:");
showPrecPrimes(drAt, dr+2);
print("\nAscending differences:");
showPrecPrimes(arAt, ar+2);
}
list(10^6) |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #Chapel | Chapel | proc calc(f, n) {
var r = 0.0;
for k in 1..n by -1 {
var v = f.pair(k);
r = v(2) / (v(1) + r);
}
return f.pair(0)(1) + r;
}
record Sqrt2 {
proc pair(n) {
return (if n == 0 then 1 else 2,
1);
}
}
record Napier {
proc pair(n) {
return (if n == 0 then 2 else n,
if n == 1 then 1 else n - 1);
}
}
record Pi {
proc pair(n) {
return (if n == 0 then 3 else 6,
(2*n - 1)**2);
}
}
config const n = 200;
writeln(calc(new Sqrt2(), n));
writeln(calc(new Napier(), n));
writeln(calc(new Pi(), n)); |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #Clojure | Clojure |
(defn cfrac
[a b n]
(letfn [(cfrac-iter [[x k]] [(+ (a k) (/ (b (inc k)) x)) (dec k)])]
(ffirst (take 1 (drop (inc n) (iterate cfrac-iter [1 n]))))))
(def sq2 (cfrac #(if (zero? %) 1.0 2.0) (constantly 1.0) 100))
(def e (cfrac #(if (zero? %) 2.0 %) #(if (= 1 %) 1.0 (double (dec %))) 100))
(def pi (cfrac #(if (zero? %) 3.0 6.0) #(let [x (- (* 2.0 %) 1.0)] (* x x)) 900000))
|
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #Fortran | Fortran | str2 = str1 |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
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
| #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
Dim s As String = "This is a string"
Dim t As String = s
' a separate copy of the string contents has been made as can be seen from the addresses
Print s, StrPtr(s)
Print t, StrPtr(t)
' to refer to the same string a pointer needs to be used
Dim u As String Ptr = @s
Print
Print *u, StrPtr(*u)
Sleep |
http://rosettacode.org/wiki/Constrained_random_points_on_a_circle | Constrained random points on a circle | Task
Generate 100 <x,y> coordinate pairs such that x and y are integers sampled from the uniform distribution with the condition that
10
≤
x
2
+
y
2
≤
15
{\displaystyle 10\leq {\sqrt {x^{2}+y^{2}}}\leq 15}
.
Then display/plot them. The outcome should be a "fuzzy" circle. The actual number of points plotted may be less than 100, given that some pairs may be generated more than once.
There are several possible approaches to accomplish this. Here are two possible algorithms.
1) Generate random pairs of integers and filter out those that don't satisfy this condition:
10
≤
x
2
+
y
2
≤
15
{\displaystyle 10\leq {\sqrt {x^{2}+y^{2}}}\leq 15}
.
2) Precalculate the set of all possible points (there are 404 of them) and select randomly from this set.
| #Action.21 | Action! | PROC DrawCircle(BYTE rmin,rmax,max,x0,y0)
BYTE count,limit
INT x,y,r2,rmin2,rmax2
limit=rmax*2+1
rmin2=rmin*rmin
rmax2=rmax*rmax
count=0
WHILE count<max
DO
x=Rand(limit) y=Rand(limit)
x==-rmax y==-rmax
r2=x*x+y*y
IF r2>=rmin2 AND r2<=rmax2 THEN
Plot(x+x0,y+y0)
count==+1
FI
OD
RETURN
PROC Main()
BYTE CH=$02FC,COLOR0=$02C4
Graphics(5+16)
Color=1
COLOR0=$0C
DrawCircle(10,15,100,40,24)
DO UNTIL CH#$FF OD
CH=$FF
RETURN |
http://rosettacode.org/wiki/Convex_hull | Convex hull | Find the points which form a convex hull from a set of arbitrary two dimensional points.
For example, given the points (16,3), (12,17), (0,6), (-4,-6), (16,6), (16,-7), (16,-3), (17,-4), (5,19), (19,-8), (3,16), (12,13), (3,-4), (17,5), (-3,15), (-3,-9), (0,11), (-9,-3), (-4,-2) and (12,10) the convex hull would be (-9,-3), (-3,-9), (19,-8), (17,5), (12,17), (5,19) and (-3,15).
See also
Convex Hull (youtube)
http://www.geeksforgeeks.org/convex-hull-set-2-graham-scan/
| #Arturo | Arturo | define :point [x y][]
orientation: function [P Q R][
val: sub (Q\y - P\y)*(R\x - Q\x) (Q\x - P\x)*(R\y - Q\y)
if val=0 -> return 0
if val>0 -> return 1
return 2
]
calculateConvexHull: function [points][
result: new []
if 3 > size points [
loop points 'p -> 'result ++ p
]
indexMinX: 0
loop.with:'i points 'p [
if p\x < get points\[indexMinX] 'x ->
indexMinX: i
]
p: indexMinX
q: 0
while [true][
'result ++ points\[p]
q: (p + 1) % size points
loop 0..dec size points 'i [
if 2 = orientation points\[p] points\[i] points\[q] ->
q: i
]
p: q
if p=indexMinX -> break
]
return result
]
points: @[
to :point [16 3],
to :point [12 17],
to :point [0 6],
to :point @[neg 4 neg 6],
to :point [16 6],
to :point @[16 neg 7],
to :point @[17 neg 4],
to :point [5 19],
to :point @[19 neg 8],
to :point [3 16],
to :point [12 13],
to :point @[3 neg 4],
to :point [17 5],
to :point @[neg 3 15],
to :point @[neg 3 neg 9],
to :point [0 11],
to :point @[neg 9 neg 3],
to :point @[neg 4 neg 2],
to :point [12 10]
]
hull: calculateConvexHull points
loop hull 'i ->
print i |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrate that it passes the following three test-cases:
Test Cases
input number
output string
7259
2 hr, 59 sec
86400
1 d
6000000
9 wk, 6 d, 10 hr, 40 min
Details
The following five units should be used:
unit
suffix used in output
conversion
week
wk
1 week = 7 days
day
d
1 day = 24 hours
hour
hr
1 hour = 60 minutes
minute
min
1 minute = 60 seconds
second
sec
However, only include quantities with non-zero values in the output (e.g., return "1 d" and not "0 wk, 1 d, 0 hr, 0 min, 0 sec").
Give larger units precedence over smaller ones as much as possible (e.g., return 2 min, 10 sec and not 1 min, 70 sec or 130 sec)
Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
| #D | D |
import std.stdio, std.conv, std.algorithm;
immutable uint SECSPERWEEK = 604_800;
immutable uint SECSPERDAY = 86_400;
immutable uint SECSPERHOUR = 3_600;
immutable uint SECSPERMIN = 60;
string ConvertSeconds(in uint seconds)
{
uint rem = seconds;
uint weeks = rem / SECSPERWEEK;
rem %= SECSPERWEEK;
uint days = rem / SECSPERDAY;
rem %= SECSPERDAY;
uint hours = rem / SECSPERHOUR;
rem %= SECSPERHOUR;
uint mins = rem / SECSPERMIN;
rem %= SECSPERMIN;
string formatted = "";
(weeks != 0) ? formatted ~= (weeks.to!string ~ " wk, ") : formatted;
(days != 0) ? formatted ~= (days.to!string ~ " d, ") : formatted;
(hours != 0) ? formatted ~= (hours.to!string ~ " hr, ") : formatted;
(mins != 0) ? formatted ~= (mins.to!string ~ " min, ") : formatted;
(rem != 0) ? formatted ~= (rem.to!string ~ " sec") : formatted;
if (formatted.endsWith(", ")) return formatted[0..$-2];
return formatted;
}
void main()
{
7_259.ConvertSeconds.writeln;
86_400.ConvertSeconds.writeln;
6_000_000.ConvertSeconds.writeln;
}
|
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Phix | Phix | include builtins\structs.e as structs
class foodbox
sequence contents = {}
procedure add(class food)
-- (aside: class food is 100% abstract here...
-- ie: class is *the* root|anything class,
-- and food is just an arbitrary name)
integer t = structs:get_field_flags(food,"eat")
if t!=SF_PROC+SF_PUBLIC then
throw("not edible") -- no public method eat...
end if
-- you might also want something like this:
-- t = structs:fetch_field(food,"eat")
-- if t=NULL then
-- throw("eat not implemented")
-- end if
this.contents = append(this.contents,food)
end procedure
procedure dine()
integer l = length(this.contents)
string s = iff(l=1?"":"s")
printf(1,"foodbox contains %d item%s\n",{l,s})
for i=1 to l do
class food = this.contents[i];
--food.eat(); -- error...
-- If you don't define an [abstract] eat() method, or use
-- "class", you end up having to do something like this:
integer eat = structs:fetch_field(food,"eat")
eat(food)
end for
end procedure
end class
foodbox lunchbox = new()
class fruit
string name
procedure eat()
printf(1,"mmm... %s\n",{this.name})
end procedure
end class
fruit banana = new({"banana"})
class clay
string name = "fletton"
end class
clay brick = new()
lunchbox.add(banana)
try
lunchbox.add(brick) -- throws exception
catch e
printf(1,"%s line %d error: %s\n",{e[E_FILE],e[E_LINE],e[E_USER]})
end try
lunchbox.dine() |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #PicoLisp | PicoLisp | (class +Eatable)
(dm eat> ()
(prinl "I'm eatable") )
(class +FoodBox)
# obj
(dm set> (Obj)
(unless (method 'eat> Obj) # Check if the object is eatable
(quit "Object is not eatable" Obj) )
(=: obj Obj) ) # If so, set the object
(let (Box (new '(+FoodBox)) Eat (new '(+Eatable)) NoEat (new '(+Bla)))
(set> Box Eat) # Works
(set> Box NoEat) ) # Gives an error |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Racket | Racket | #lang racket
(module+ test (require tests/eli-tester))
;; This is all that an object should need to properly implement.
(define edible<%>
(interface () [eat (->m void?)]))
(define (generic-container<%> containee/c)
(interface ()
[contents (->m (listof containee/c))]
[insert (->m containee/c void?)]
[remove-at (->m exact-nonnegative-integer? containee/c)]
[count (->m exact-nonnegative-integer?)]))
(define ((generic-box-mixin containee/c) %)
(->i ([containee/c contract?])
(rv (containee/c) (implementation?/c (generic-container<%> containee/c))))
(class* % ((generic-container<%> containee/c))
(super-new)
(define l empty)
(define/public (contents) l)
(define/public (insert o) (set! l (cons o l)))
(define/public (remove-at i)
(begin0 (list-ref l i)
(append (take l i) (drop l (add1 i)))))
(define/public (count) (length l))))
;; As I understand it, a "Food Box" from the task is still a generic... i.e.
;; you will specify it down ;; to an "apple-box%" so: food-box%-generic is still
;; generic. food-box% will take any kind of food.
(define/contract (food-box-mixin T%)
(-> (or/c (λ (i) (eq? edible<%> i)) (implementation?/c edible<%>))
(make-mixin-contract))
(generic-box-mixin (and/c (is-a?/c edible<%>) (is-a?/c T%))))
(module+ test
(define integer-box% ((generic-box-mixin integer?) object%))
(define integer-box (new integer-box%))
(define apple%
(class* object% (edible<%>)
(super-new)
(define/public (eat)
(displayln "nom!"))))
(define banana%
(class* object% (edible<%>)
(super-new)
(define/public (eat)
(displayln "peel.. peel... nom... nom!"))))
(define semolina%
(class* object% () ; <-- empty interfaces clause
(super-new)
;; you can call eat on it... but it's not explicitly (or even vaguely)
;; edible<%>
(define/public (eat) (displayln "blech!"))))
;; this will take any object that is edible<%> and edible<%> (therefore all
;; edible<%> objects)
(define any-food-box (new ((food-box-mixin edible<%>) object%)))
;; this will take any object that is edible and an apple<%>
;; (therefore only apple<%>s)
(define apple-food-box (new ((food-box-mixin apple%) object%)))
(test
;; Test generic boxes
(send integer-box insert 22)
(send integer-box insert "a string") =error> exn:fail:contract?
;; Test the food box that takes any edible<%>
(send any-food-box insert (new apple%))
(send any-food-box insert (new banana%))
(send any-food-box insert (new semolina%)) =error> exn:fail:contract?
;; Test the food box that takes any apple%
(send apple-food-box insert (new apple%))
(send apple-food-box insert (new banana%)) =error> exn:fail:contract?
(send apple-food-box insert (new semolina%)) =error> exn:fail:contract?
(send apple-food-box count) => 1
;; Show that you cannot make a food-box from the non-edible<%> semolina cannot
(implementation? semolina% edible<%>) => #f
(new ((food-box-mixin semolina%) object%)) =error> exn:fail:contract?)) |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a generic type FoodBox which contains a collection of objects of
a type given as parameter, but can only be instantiated on eatable types.
The FoodBox shall not use the function eat in any way (i.e. without the explicit restriction, it could be instantiated on any type).
The specification of a type being eatable should be as generic as possible
in your language (i.e. the restrictions on the implementation of eatable types
should be as minimal as possible).
Also explain the restrictions, if any, on the implementation of eatable types,
and show at least one example of an eatable type.
| #Raku | Raku | subset Eatable of Any where { .^can('eat') };
class Cake { method eat() {...} }
role FoodBox[Eatable] {
has %.foodbox;
}
class Yummy does FoodBox[Cake] { } # composes correctly
# class Yucky does FoodBox[Int] { } # fails to compose
my Yummy $foodbox .= new;
say $foodbox; |
http://rosettacode.org/wiki/Consecutive_primes_with_ascending_or_descending_differences | Consecutive primes with ascending or descending differences | Task
Find and display here on this page, the longest sequence of consecutive prime numbers where the differences between the primes are strictly ascending.
Do the same for sequences of primes where the differences are strictly descending.
In both cases, show the sequence for primes < 1,000,000.
If there are multiple sequences of the same length, only the first need be shown.
| #Perl | Perl | use strict;
use warnings;
use feature 'say';
use ntheory 'primes';
use List::AllUtils <indexes max>;
my $limit = 1000000;
my @primes = @{primes( $limit )};
sub runs {
my($op) = @_;
my @diff = my $diff = my $run = 1;
push @diff, map {
my $next = $primes[$_] - $primes[$_ - 1];
if ($op eq '>') { if ($next > $diff) { ++$run } else { $run = 1 } }
else { if ($next < $diff) { ++$run } else { $run = 1 } }
$diff = $next;
$run
} 1 .. $#primes;
my @prime_run;
my $max = max @diff;
for my $r ( indexes { $_ == $max } @diff ) {
push @prime_run, join ' ', map { $primes[$r - $_] } reverse 0..$max
}
@prime_run
}
say "Longest run(s) of ascending prime gaps up to $limit:\n" . join "\n", runs('>');
say "\nLongest run(s) of descending prime gaps up to $limit:\n" . join "\n", runs('<'); |
http://rosettacode.org/wiki/Continued_fraction | Continued fraction | continued fraction
Mathworld
a
0
+
b
1
a
1
+
b
2
a
2
+
b
3
a
3
+
⋱
{\displaystyle a_{0}+{\cfrac {b_{1}}{a_{1}+{\cfrac {b_{2}}{a_{2}+{\cfrac {b_{3}}{a_{3}+\ddots }}}}}}}
The task is to write a program which generates such a number and prints a real representation of it. The code should be tested by calculating and printing the square root of 2, Napier's Constant, and Pi, using the following coefficients:
For the square root of 2, use
a
0
=
1
{\displaystyle a_{0}=1}
then
a
N
=
2
{\displaystyle a_{N}=2}
.
b
N
{\displaystyle b_{N}}
is always
1
{\displaystyle 1}
.
2
=
1
+
1
2
+
1
2
+
1
2
+
⋱
{\displaystyle {\sqrt {2}}=1+{\cfrac {1}{2+{\cfrac {1}{2+{\cfrac {1}{2+\ddots }}}}}}}
For Napier's Constant, use
a
0
=
2
{\displaystyle a_{0}=2}
, then
a
N
=
N
{\displaystyle a_{N}=N}
.
b
1
=
1
{\displaystyle b_{1}=1}
then
b
N
=
N
−
1
{\displaystyle b_{N}=N-1}
.
e
=
2
+
1
1
+
1
2
+
2
3
+
3
4
+
⋱
{\displaystyle e=2+{\cfrac {1}{1+{\cfrac {1}{2+{\cfrac {2}{3+{\cfrac {3}{4+\ddots }}}}}}}}}
For Pi, use
a
0
=
3
{\displaystyle a_{0}=3}
then
a
N
=
6
{\displaystyle a_{N}=6}
.
b
N
=
(
2
N
−
1
)
2
{\displaystyle b_{N}=(2N-1)^{2}}
.
π
=
3
+
1
6
+
9
6
+
25
6
+
⋱
{\displaystyle \pi =3+{\cfrac {1}{6+{\cfrac {9}{6+{\cfrac {25}{6+\ddots }}}}}}}
See also
Continued fraction/Arithmetic for tasks that do arithmetic over continued fractions.
| #COBOL | COBOL | identification division.
program-id. show-continued-fractions.
environment division.
configuration section.
repository.
function continued-fractions
function all intrinsic.
procedure division.
fractions-main.
display "Square root 2 approximately : "
continued-fractions("sqrt-2-alpha", "sqrt-2-beta", 100)
display "Napier constant approximately : "
continued-fractions("napier-alpha", "napier-beta", 40)
display "Pi approximately : "
continued-fractions("pi-alpha", "pi-beta", 10000)
goback.
end program show-continued-fractions.
*> **************************************************************
identification division.
function-id. continued-fractions.
data division.
working-storage section.
01 alpha-function usage program-pointer.
01 beta-function usage program-pointer.
01 alpha usage float-long.
01 beta usage float-long.
01 running usage float-long.
01 i usage binary-long.
linkage section.
01 alpha-name pic x any length.
01 beta-name pic x any length.
01 iterations pic 9 any length.
01 approximation usage float-long.
procedure division using
alpha-name beta-name iterations
returning approximation.
set alpha-function to entry alpha-name
if alpha-function = null then
display "error: no " alpha-name " function" upon syserr
goback
end-if
set beta-function to entry beta-name
if beta-function = null then
display "error: no " beta-name " function" upon syserr
goback
end-if
move 0 to alpha beta running
perform varying i from iterations by -1 until i = 0
call alpha-function using i returning alpha
call beta-function using i returning beta
compute running = beta / (alpha + running)
end-perform
call alpha-function using 0 returning alpha
compute approximation = alpha + running
goback.
end function continued-fractions.
*> ******************************
identification division.
program-id. sqrt-2-alpha.
data division.
working-storage section.
01 result usage float-long.
linkage section.
01 iteration usage binary-long unsigned.
procedure division using iteration returning result.
if iteration equal 0 then
move 1.0 to result
else
move 2.0 to result
end-if
goback.
end program sqrt-2-alpha.
*> ******************************
identification division.
program-id. sqrt-2-beta.
data division.
working-storage section.
01 result usage float-long.
linkage section.
01 iteration usage binary-long unsigned.
procedure division using iteration returning result.
move 1.0 to result
goback.
end program sqrt-2-beta.
*> ******************************
identification division.
program-id. napier-alpha.
data division.
working-storage section.
01 result usage float-long.
linkage section.
01 iteration usage binary-long unsigned.
procedure division using iteration returning result.
if iteration equal 0 then
move 2.0 to result
else
move iteration to result
end-if
goback.
end program napier-alpha.
*> ******************************
identification division.
program-id. napier-beta.
data division.
working-storage section.
01 result usage float-long.
linkage section.
01 iteration usage binary-long unsigned.
procedure division using iteration returning result.
if iteration = 1 then
move 1.0 to result
else
compute result = iteration - 1.0
end-if
goback.
end program napier-beta.
*> ******************************
identification division.
program-id. pi-alpha.
data division.
working-storage section.
01 result usage float-long.
linkage section.
01 iteration usage binary-long unsigned.
procedure division using iteration returning result.
if iteration equal 0 then
move 3.0 to result
else
move 6.0 to result
end-if
goback.
end program pi-alpha.
*> ******************************
identification division.
program-id. pi-beta.
data division.
working-storage section.
01 result usage float-long.
linkage section.
01 iteration usage binary-long unsigned.
procedure division using iteration returning result.
compute result = (2 * iteration - 1) ** 2
goback.
end program pi-beta.
|
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