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http://rosettacode.org/wiki/Fusc_sequence
Fusc sequence
Definitions The   fusc   integer sequence is defined as:   fusc(0) = 0   fusc(1) = 1   for n>1,   the   nth   term is defined as:   if   n   is even;     fusc(n) = fusc(n/2)   if   n   is   odd;     fusc(n) = fusc((n-1)/2)   +   fusc((n+1)/2) Note that MathWorld's definition starts with unity, not zero.   This task will be using the OEIS' version   (above). An observation   fusc(A) = fusc(B) where   A   is some non-negative integer expressed in binary,   and where   B   is the binary value of   A   reversed. Fusc numbers are also known as:   fusc function   (named by Dijkstra, 1982)   Stern's Diatomic series   (although it starts with unity, not zero)   Stern-Brocot sequence   (although it starts with unity, not zero) Task   show the first   61   fusc numbers (starting at zero) in a horizontal format.   show the fusc number (and its index) whose length is greater than any previous fusc number length.   (the length is the number of decimal digits when the fusc number is expressed in base ten.)   show all numbers with commas   (if appropriate).   show all output here. Related task   RosettaCode Stern-Brocot sequence Also see   the MathWorld entry:   Stern's Diatomic Series.   the OEIS entry:   A2487.
#C
C
  #include<limits.h> #include<stdio.h>   int fusc(int n){ if(n==0||n==1) return n; else if(n%2==0) return fusc(n/2); else return fusc((n-1)/2) + fusc((n+1)/2); }   int numLen(int n){ int sum = 1;   while(n>9){ n = n/10; sum++; }   return sum; }   void printLargeFuscs(int limit){ int i,f,len,maxLen = 1;   printf("\n\nPrinting all largest Fusc numbers upto %d \nIndex-------Value",limit);   for(i=0;i<=limit;i++){ f = fusc(i); len = numLen(f);   if(len>maxLen){ maxLen = len; printf("\n%5d%12d",i,f); } } }     int main() { int i;   printf("Index-------Value"); for(i=0;i<61;i++) printf("\n%5d%12d",i,fusc(i)); printLargeFuscs(INT_MAX); return 0; }  
http://rosettacode.org/wiki/Functional_coverage_tree
Functional coverage tree
Functional coverage is a measure of how much a particular function of a system has been verified as correct. It is used heavily in tracking the completeness of the verification of complex System on Chip (SoC) integrated circuits, where it can also be used to track how well the functional requirements of the system have been verified. This task uses a sub-set of the calculations sometimes used in tracking functional coverage but uses a more familiar(?) scenario. Task Description The head of the clean-up crews for "The Men in a very dark shade of grey when viewed at night" has been tasked with managing the cleansing of two properties after an incident involving aliens. She arranges the task hierarchically with a manager for the crews working on each house who return with a breakdown of how they will report on progress in each house. The overall hierarchy of (sub)tasks is as follows, cleaning house1 bedrooms bathrooms bathroom1 bathroom2 outside lavatory attic kitchen living rooms lounge dining room conservatory playroom basement garage garden house2 upstairs bedrooms suite 1 suite 2 bedroom 3 bedroom 4 bathroom toilet attics groundfloor kitchen living rooms lounge dining room conservatory playroom wet room & toilet garage garden hot tub suite basement cellars wine cellar cinema The head of cleanup knows that her managers will report fractional completion of leaf tasks (tasks with no child tasks of their own), and she knows that she will want to modify the weight of values of completion as she sees fit. Some time into the cleaning, and some coverage reports have come in and she thinks see needs to weight the big house2 60-40 with respect to coverage from house1 She prefers a tabular view of her data where missing weights are assumed to be 1.0 and missing coverage 0.0. NAME_HIERARCHY |WEIGHT |COVERAGE | cleaning | | | house1 |40 | | bedrooms | |0.25 | bathrooms | | | bathroom1 | |0.5 | bathroom2 | | | outside_lavatory | |1 | attic | |0.75 | kitchen | |0.1 | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | |1 | basement | | | garage | | | garden | |0.8 | house2 |60 | | upstairs | | | bedrooms | | | suite_1 | | | suite_2 | | | bedroom_3 | | | bedroom_4 | | | bathroom | | | toilet | | | attics | |0.6 | groundfloor | | | kitchen | | | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | | | wet_room_&_toilet | | | garage | | | garden | |0.9 | hot_tub_suite | |1 | basement | | | cellars | |1 | wine_cellar | |1 | cinema | |0.75 | Calculation The coverage of a node in the tree is calculated as the weighted average of the coverage of its children evaluated bottom-upwards in the tree. The task is to calculate the overall coverage of the cleaning task and display the coverage at all levels of the hierarchy on this page, in a manner that visually shows the hierarchy, weights and coverage of all nodes. Extra Credit After calculating the coverage for all nodes, one can also calculate the additional/delta top level coverage that would occur if any (sub)task were to be fully covered from its current fractional coverage. This is done by multiplying the extra coverage that could be gained 1 − c o v e r a g e {\displaystyle 1-coverage} for any node, by the product of the `powers` of its parent nodes from the top down to the node. The power of a direct child of any parent is given by the power of the parent multiplied by the weight of the child divided by the sum of the weights of all the direct children. The pseudo code would be: method delta_calculation(this, power): sum_of_weights = sum(node.weight for node in children) this.delta = (1 - this.coverage) * power for node in self.children: node.delta_calculation(power * node.weight / sum_of_weights) return this.delta Followed by a call to: top.delta_calculation(power=1) Note: to aid in getting the data into your program you might want to use an alternative, more functional description of the starting data given on the discussion page.
#Swift
Swift
import Foundation   extension String { func paddedLeft(totalLen: Int) -> String { let needed = totalLen - count   guard needed > 0 else { return self }   return String(repeating: " ", count: needed) + self } }   class FCNode { let name: String let weight: Int   var coverage: Double { didSet { if oldValue != coverage { parent?.updateCoverage() } } }   weak var parent: FCNode? var children = [FCNode]()   init(name: String, weight: Int = 1, coverage: Double = 0) { self.name = name self.weight = weight self.coverage = coverage }   func addChildren(_ children: [FCNode]) { for child in children { child.parent = self }   self.children += children   updateCoverage() }   func show(level: Int = 0) { let indent = level * 4 let nameLen = name.count + indent   print(name.paddedLeft(totalLen: nameLen), terminator: "") print("|".paddedLeft(totalLen: 32 - nameLen), terminator: "") print(String(format: "  %3d |", weight), terminator: "") print(String(format: " %8.6f |", coverage))   for child in children { child.show(level: level + 1) } }   func updateCoverage() { let v1 = children.reduce(0.0, { $0 + $1.coverage * Double($1.weight) }) let v2 = children.reduce(0.0, { $0 + Double($1.weight) })   coverage = v1 / v2 } }   let houses = [ FCNode(name: "house1", weight: 40), FCNode(name: "house2", weight: 60) ]   let house1 = [ FCNode(name: "bedrooms", weight: 1, coverage: 0.25), FCNode(name: "bathrooms"), FCNode(name: "attic", weight: 1, coverage: 0.75), FCNode(name: "kitchen", weight: 1, coverage: 0.1), FCNode(name: "living_rooms"), FCNode(name: "basement"), FCNode(name: "garage"), FCNode(name: "garden", weight: 1, coverage: 0.8) ]   let house2 = [ FCNode(name: "upstairs"), FCNode(name: "groundfloor"), FCNode(name: "basement") ]   let h1Bathrooms = [ FCNode(name: "bathroom1", weight: 1, coverage: 0.5), FCNode(name: "bathroom2"), FCNode(name: "outside_lavatory", weight: 1, coverage: 1.0) ]   let h1LivingRooms = [ FCNode(name: "lounge"), FCNode(name: "dining_room"), FCNode(name: "conservatory"), FCNode(name: "playroom", weight: 1, coverage: 1.0) ]   let h2Upstairs = [ FCNode(name: "bedrooms"), FCNode(name: "bathroom"), FCNode(name: "toilet"), FCNode(name: "attics", weight: 1, coverage: 0.6) ]   let h2Groundfloor = [ FCNode(name: "kitchen"), FCNode(name: "living_rooms"), FCNode(name: "wet_room_&_toilet"), FCNode(name: "garage"), FCNode(name: "garden", weight: 1, coverage: 0.9), FCNode(name: "hot_tub_suite", weight: 1, coverage: 1.0) ]   let h2Basement = [ FCNode(name: "cellars", weight: 1, coverage: 1.0), FCNode(name: "wine_cellar", weight: 1, coverage: 1.0), FCNode(name: "cinema", weight: 1, coverage: 0.75) ]   let h2UpstairsBedrooms = [ FCNode(name: "suite_1"), FCNode(name: "suite_2"), FCNode(name: "bedroom_3"), FCNode(name: "bedroom_4") ]   let h2GroundfloorLivingRooms = [ FCNode(name: "lounge"), FCNode(name: "dining_room"), FCNode(name: "conservatory"), FCNode(name: "playroom") ]   let cleaning = FCNode(name: "cleaning")   house1[1].addChildren(h1Bathrooms) house1[4].addChildren(h1LivingRooms) houses[0].addChildren(house1)   h2Upstairs[0].addChildren(h2UpstairsBedrooms) house2[0].addChildren(h2Upstairs) h2Groundfloor[1].addChildren(h2GroundfloorLivingRooms) house2[1].addChildren(h2Groundfloor) house2[2].addChildren(h2Basement) houses[1].addChildren(house2)   cleaning.addChildren(houses)   let top = cleaning.coverage   print("Top Coverage: \(String(format: "%8.6f", top))") print("Name Hierarchy | Weight | Coverage |")   cleaning.show()   h2Basement[2].coverage = 1.0   let diff = cleaning.coverage - top   print("\nIf the coverage of the Cinema node were increased from 0.75 to 1.0") print("the top level coverage would increase by ") print("\(String(format: "%8.6f", diff)) to \(String(format: "%8.6f", top))")
http://rosettacode.org/wiki/Functional_coverage_tree
Functional coverage tree
Functional coverage is a measure of how much a particular function of a system has been verified as correct. It is used heavily in tracking the completeness of the verification of complex System on Chip (SoC) integrated circuits, where it can also be used to track how well the functional requirements of the system have been verified. This task uses a sub-set of the calculations sometimes used in tracking functional coverage but uses a more familiar(?) scenario. Task Description The head of the clean-up crews for "The Men in a very dark shade of grey when viewed at night" has been tasked with managing the cleansing of two properties after an incident involving aliens. She arranges the task hierarchically with a manager for the crews working on each house who return with a breakdown of how they will report on progress in each house. The overall hierarchy of (sub)tasks is as follows, cleaning house1 bedrooms bathrooms bathroom1 bathroom2 outside lavatory attic kitchen living rooms lounge dining room conservatory playroom basement garage garden house2 upstairs bedrooms suite 1 suite 2 bedroom 3 bedroom 4 bathroom toilet attics groundfloor kitchen living rooms lounge dining room conservatory playroom wet room & toilet garage garden hot tub suite basement cellars wine cellar cinema The head of cleanup knows that her managers will report fractional completion of leaf tasks (tasks with no child tasks of their own), and she knows that she will want to modify the weight of values of completion as she sees fit. Some time into the cleaning, and some coverage reports have come in and she thinks see needs to weight the big house2 60-40 with respect to coverage from house1 She prefers a tabular view of her data where missing weights are assumed to be 1.0 and missing coverage 0.0. NAME_HIERARCHY |WEIGHT |COVERAGE | cleaning | | | house1 |40 | | bedrooms | |0.25 | bathrooms | | | bathroom1 | |0.5 | bathroom2 | | | outside_lavatory | |1 | attic | |0.75 | kitchen | |0.1 | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | |1 | basement | | | garage | | | garden | |0.8 | house2 |60 | | upstairs | | | bedrooms | | | suite_1 | | | suite_2 | | | bedroom_3 | | | bedroom_4 | | | bathroom | | | toilet | | | attics | |0.6 | groundfloor | | | kitchen | | | living_rooms | | | lounge | | | dining_room | | | conservatory | | | playroom | | | wet_room_&_toilet | | | garage | | | garden | |0.9 | hot_tub_suite | |1 | basement | | | cellars | |1 | wine_cellar | |1 | cinema | |0.75 | Calculation The coverage of a node in the tree is calculated as the weighted average of the coverage of its children evaluated bottom-upwards in the tree. The task is to calculate the overall coverage of the cleaning task and display the coverage at all levels of the hierarchy on this page, in a manner that visually shows the hierarchy, weights and coverage of all nodes. Extra Credit After calculating the coverage for all nodes, one can also calculate the additional/delta top level coverage that would occur if any (sub)task were to be fully covered from its current fractional coverage. This is done by multiplying the extra coverage that could be gained 1 − c o v e r a g e {\displaystyle 1-coverage} for any node, by the product of the `powers` of its parent nodes from the top down to the node. The power of a direct child of any parent is given by the power of the parent multiplied by the weight of the child divided by the sum of the weights of all the direct children. The pseudo code would be: method delta_calculation(this, power): sum_of_weights = sum(node.weight for node in children) this.delta = (1 - this.coverage) * power for node in self.children: node.delta_calculation(power * node.weight / sum_of_weights) return this.delta Followed by a call to: top.delta_calculation(power=1) Note: to aid in getting the data into your program you might want to use an alternative, more functional description of the starting data given on the discussion page.
#Wren
Wren
import "/fmt" for Fmt   class FCNode { construct new(name, weight, coverage) { _name = name _weight = weight _coverage = coverage _children = [] _parent = null }   static new(name, weight) { new(name, weight, 0) } static new(name) { new(name, 1, 0) }   name { _name } weight { _weight } coverage { _coverage }   coverage=(value) { if (_coverage != value) { _coverage = value if (_parent) { _parent.updateCoverage_() // update any parent's coverage } } }   parent { _parent } parent=(p) { _parent = p }   addChildren(nodes) { _children.addAll(nodes) for (node in nodes) node.parent = this updateCoverage_() }   updateCoverage_() { var v1 = _children.reduce(0) { |acc, n| acc + n.weight * n.coverage } var v2 = _children.reduce(0) { |acc, n| acc + n.weight } coverage = v1 / v2 }   show(level) { var indent = level * 4 var nl = _name.count + indent Fmt.lprint("$*s$*s $3d | $8.6f |", [nl, _name, 32-nl, "|", _weight, _coverage]) if (_children.isEmpty) return for (child in _children) child.show(level+1) } }   var houses = [ FCNode.new("house1", 40), FCNode.new("house2", 60) ]   var house1 = [ FCNode.new("bedrooms", 1, 0.25), FCNode.new("bathrooms"), FCNode.new("attic", 1, 0.75), FCNode.new("kitchen", 1, 0.1), FCNode.new("living_rooms"), FCNode.new("basement"), FCNode.new("garage"), FCNode.new("garden", 1, 0.8) ]   var house2 = [ FCNode.new("upstairs"), FCNode.new("groundfloor"), FCNode.new("basement") ]   var h1Bathrooms = [ FCNode.new("bathroom1", 1, 0.5), FCNode.new("bathroom2"), FCNode.new("outside_lavatory", 1, 1) ]   var h1LivingRooms = [ FCNode.new("lounge"), FCNode.new("dining_room"), FCNode.new("conservatory"), FCNode.new("playroom", 1, 1) ]   var h2Upstairs = [ FCNode.new("bedrooms"), FCNode.new("bathroom"), FCNode.new("toilet"), FCNode.new("attics", 1, 0.6) ]   var h2Groundfloor = [ FCNode.new("kitchen"), FCNode.new("living_rooms"), FCNode.new("wet_room_&_toilet"), FCNode.new("garage"), FCNode.new("garden", 1, 0.9), FCNode.new("hot_tub_suite", 1, 1) ]   var h2Basement = [ FCNode.new("cellars", 1, 1), FCNode.new("wine_cellar", 1, 1), FCNode.new("cinema", 1, 0.75) ]   var h2UpstairsBedrooms = [ FCNode.new("suite_1"), FCNode.new("suite_2"), FCNode.new("bedroom_3"), FCNode.new("bedroom_4") ]   var h2GroundfloorLivingRooms = [ FCNode.new("lounge"), FCNode.new("dining_room"), FCNode.new("conservatory"), FCNode.new("playroom") ]   var cleaning = FCNode.new("cleaning")   house1[1].addChildren(h1Bathrooms) house1[4].addChildren(h1LivingRooms) houses[0].addChildren(house1)   h2Upstairs[0].addChildren(h2UpstairsBedrooms) house2[0].addChildren(h2Upstairs) h2Groundfloor[1].addChildren(h2GroundfloorLivingRooms) house2[1].addChildren(h2Groundfloor) house2[2].addChildren(h2Basement) houses[1].addChildren(house2)   cleaning.addChildren(houses) var topCoverage = cleaning.coverage Fmt.print("TOP COVERAGE = $8.6f\n", topCoverage) System.print("NAME HIERARCHY | WEIGHT | COVERAGE |") cleaning.show(0)   h2Basement[2].coverage = 1 // change Cinema node coverage to 1 var diff = cleaning.coverage - topCoverage System.print("\nIf the coverage of the Cinema node were increased from 0.75 to 1") System.write("the top level coverage would increase by ") Fmt.print("$8.6f to $8.6f", diff, topCoverage + diff) h2Basement[2].coverage = 0.75 // restore to original value if required
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Julia
Julia
using Printf, DataStructures   function funcfreqs(expr::Expr) cnt = counter(Symbol) expr.head == :call && push!(cnt, expr.args[1]) for e in expr.args e isa Expr && merge!(cnt, funcfreqs(e)) end return cnt end   function parseall(str::AbstractString) exs = Any[] pos = start(str) while !done(str, pos) ex, pos = parse(str, pos) # returns next starting point as well as expr ex.head == :toplevel ? append!(exs, ex.args) : push!(exs, ex) end if isempty(exs) throw(ParseError("end of input")) elseif length(exs) == 1 return exs[1] else return Expr(:block, exs...) end end   freqs = readstring("src/Function_frequency.jl") |> parseall |> funcfreqs   for (v, f) in freqs @printf("%10s → %i\n", v, f) end
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#LiveCode
LiveCode
function handlerNames pScript put pScript into pScriptCopy filter pScript with regex pattern "^(on|function).*" -- add in the built-in commands & functions put the commandNames & the functionnames into cmdfunc repeat for each line builtin in cmdfunc put 0 into handlers[builtin] end repeat   -- add user defined handlers, remove this section of you do not want your own functions included repeat with x = 1 to the number of lines of pScript put word 2 of line x of pScript into handlername put 0 into handlers[handlername] end repeat   -- count handlers used repeat with x = 1 to the number of lines of pScriptCopy repeat for each key k in handlers if k is among the tokens of line x of pScriptCopy then add 1 to handlers[k] end if end repeat end repeat   combine handlers using cr and space sort lines of handlers descending by word 2 of each put line 1 to 10 of handlers into handlers return handlers end handlerNames
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
programCount[fn_] := Reverse[If[Length[#] > 10, Take[#, -10], #] &[SortBy[Tally[Cases[DownValues[fn], s_Symbol, \[Infinity], Heads -> True]], Last]]]
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#C.23
C#
using System; using System.Numerics;   static int g = 7; static double[] p = {0.99999999999980993, 676.5203681218851, -1259.1392167224028, 771.32342877765313, -176.61502916214059, 12.507343278686905, -0.13857109526572012, 9.9843695780195716e-6, 1.5056327351493116e-7};   Complex Gamma(Complex z) { // Reflection formula if (z.Real < 0.5) { return Math.PI / (Complex.Sin( Math.PI * z) * Gamma(1 - z)); } else { z -= 1; Complex x = p[0]; for (var i = 1; i < g + 2; i++) { x += p[i]/(z+i); } Complex t = z + g + 0.5; return Complex.Sqrt(2 * Math.PI) * (Complex.Pow(t, z + 0.5)) * Complex.Exp(-t) * x; } }  
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#J
J
initpins=: '* ' {~ '1'&i.@(-@|. |."_1 [: ":@-.&0"1 <:~/~)@i.
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Groovy
Groovy
class GapfulNumbers { private static String commatize(long n) { StringBuilder sb = new StringBuilder(Long.toString(n)) int le = sb.length() for (int i = le - 3; i >= 1; i -= 3) { sb.insert(i, ',') } return sb.toString() }   static void main(String[] args) { List<Long> starts = [(long) 1e2, (long) 1e6, (long) 1e7, (long) 1e9, (long) 7123] List<Integer> counts = [30, 15, 15, 10, 25] for (int i = 0; i < starts.size(); ++i) { println("First ${counts.get(i)} gapful numbers starting at ${commatize(starts.get(i))}")   long j = starts.get(i) long pow = 100 while (j >= pow * 10) { pow *= 10 }   int count = 0 while (count < counts.get(i)) { long fl = ((long) (j / pow)) * 10 + (j % 10) if (j % fl == 0) { print("$j ") count++ } if (++j >= 10 * pow) { pow *= 10 } }   println() println() } } }
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#J
J
  f=: 6j2&": NB. formatting verb   sin=: 1&o. NB. verb to evaluate circle function 1, the sine   add_noise=: ] + (* (_0.5 + 0 ?@:#~ #)) NB. AMPLITUDE add_noise SIGNAL   f RADIANS=: o.@:(%~ i.@:>:)5 NB. monadic circle function is pi times 0.00 0.63 1.26 1.88 2.51 3.14   f SINES=: sin RADIANS 0.00 0.59 0.95 0.95 0.59 0.00   f NOISY_SINES=: 0.1 add_noise SINES _0.01 0.61 0.91 0.99 0.60 0.02   A=: (^/ i.@:#) RADIANS NB. A is the quintic coefficient matrix   NB. display the equation to solve (f A) ; 'x' ; '=' ; f@:,. NOISY_SINES ┌────────────────────────────────────┬─┬─┬──────┐ │ 1.00 0.00 0.00 0.00 0.00 0.00│x│=│ _0.01│ │ 1.00 0.63 0.39 0.25 0.16 0.10│ │ │ 0.61│ │ 1.00 1.26 1.58 1.98 2.49 3.13│ │ │ 0.91│ │ 1.00 1.88 3.55 6.70 12.62 23.80│ │ │ 0.99│ │ 1.00 2.51 6.32 15.88 39.90100.28│ │ │ 0.60│ │ 1.00 3.14 9.87 31.01 97.41306.02│ │ │ 0.02│ └────────────────────────────────────┴─┴─┴──────┘   f QUINTIC_COEFFICIENTS=: NOISY_SINES %. A NB. %. solves the linear system _0.01 1.71 _1.88 1.48 _0.58 0.08   quintic=: QUINTIC_COEFFICIENTS&p. NB. verb to evaluate the polynomial   NB. %. also solves the least squares fit for overdetermined system quadratic=: (NOISY_SINES %. (^/ i.@:3:) RADIANS)&p. NB. verb to evaluate quadratic. quadratic _0.0200630695393961729 1.26066877804926536 _0.398275112136019516&p.   NB. The quintic is agrees with the noisy data, as it should f@:(NOISY_SINES ,. sin ,. quadratic ,. quintic) RADIANS _0.01 0.00 _0.02 _0.01 0.61 0.59 0.61 0.61 0.91 0.95 0.94 0.91 0.99 0.95 0.94 0.99 0.60 0.59 0.63 0.60 0.02 0.00 0.01 0.02   f MID_POINTS=: (+ -:@:(-/@:(2&{.)))RADIANS _0.31 0.31 0.94 1.57 2.20 2.83   f@:(sin ,. quadratic ,. quintic) MID_POINTS _0.31 _0.46 _0.79 0.31 0.34 0.38 0.81 0.81 0.77 1.00 0.98 1.00 0.81 0.83 0.86 0.31 0.36 0.27  
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Nim
Nim
import strformat, strutils   const Eps = 1e-10   type Matrix[M, N: static Positive] = array[M, array[N, float]] SquareMatrix[N: static Positive] = Matrix[N, N]     func toSquareMatrix[N: static Positive](a: array[N, array[N, int]]): SquareMatrix[N] = ## Convert a square matrix of integers to a square matrix of floats.   for i in 0..<N: for j in 0..<N: result[i][j] = a[i][j].toFloat     func transformToRref(mat: var Matrix) = ## Transform a matrix to reduced row echelon form.   var lead = 0   for r in 0..<mat.M:   if lead >= mat.N: return   var i = r while mat[i][lead] == 0: inc i if i == mat.M: i = r inc lead if lead == mat.N: return swap mat[i], mat[r]   let d = mat[r][lead] if abs(d) > Eps: # Checking "d != 0" will give wrong results in some cases. for item in mat[r].mitems: item /= d   for i in 0..<mat.M: if i != r: let m = mat[i][lead] for c in 0..<mat.N: mat[i][c] -= mat[r][c] * m   inc lead     func inverse(mat: SquareMatrix): SquareMatrix[mat.N] = ## Return the inverse of a matrix.   # Build augmented matrix. var augmat: Matrix[mat.N, 2 * mat.N] for i in 0..<mat.N: augmat[i][0..<mat.N] = mat[i] augmat[i][mat.N + i] = 1   # Transform it to reduced row echelon form. augmat.transformToRref()   # Check if the first half is the identity matrix and extract second half. for i in 0..<mat.N: for j in 0..<mat.N: if augmat[i][j] != float(i == j): raise newException(ValueError, "matrix is singular") result[i][j] = augmat[i][mat.N + j]     proc `$`(mat: Matrix): string = ## Display a matrix (which may be a square matrix).   for row in mat: var line = "" for val in row: line.addSep(" ", 0) line.add &"{val:9.5f}" echo line     #———————————————————————————————————————————————————————————————————————————————————————————————————   template runTest(mat: SquareMatrix) = ## Run a test using square matrix "mat".   echo "Matrix:" echo $mat echo "Inverse:" echo mat.inverse echo ""   let m1 = [[1, 2, 3], [4, 1, 6], [7, 8, 9]].toSquareMatrix()   let m2 = [[ 2, -1, 0], [-1, 2, -1], [ 0, -1, 2]].toSquareMatrix()   let m3 = [[ -1, -2, 3, 2], [ -4, -1, 6, 2], [ 7, -8, 9, 1], [ 1, -2, 1, 3]].toSquareMatrix()   runTest(m1) runTest(m2) runTest(m3)
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Maple
Maple
findNum := proc(str) #help parse input local i; i := 1: while (true) do if (StringTools:-IsAlpha(str[i])) then return i-2: end if: i := i+1: end do: end proc: path := "input.txt"; input := readline(path): T := table(): maxnum := parse(input): while (true) do input := readline(path): if input = 0 then break; end if: pos := findNum(input): num := parse(input[..pos]): T[num] := input[pos+2..]: end do: for i from 1 to maxnum do factored := false: for j in [indices(T)] do if i mod j[1] = 0 then factored := true: printf(T[j[1]]); end if: end do: if (not factored) then printf("%d", i): end if: printf("\n"); end do:
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
list={{5,"Buzz"},{3,"Fizz"},{7,"Baxx"}}; runTo=(*LCM@@list[[All,1]]+1*)20; Column@Table[ Select[list,Mod[x,#[[1]]]==0&][[All,2]]/.{}->{x} ,{x,1,runTo} ]
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Erlang
Erlang
lists:seq($a,$z).
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Excel
Excel
showAlphabet =LAMBDA(az, ENUMFROMTOCHAR( MID(az, 1, 1) )( MID(az, 2, 1) ) )
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#OpenLisp
OpenLisp
  #!/openlisp/uxlisp -shell (format t "Hello world!~%") (print "Hello world!")  
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
lastsquare = 1; nextsquare = -1; lastcube = -1; midcube = 0; nextcube = 1; Gensquares[] := Module[{}, lastsquare += nextsquare; nextsquare += 2; squares = lastsquare; squares ] Gencubes[] := Module[{}, lastcube += nextcube; nextcube += midcube; midcube += 6; cubes = lastcube ]     c = Gencubes[]; Do[ While[True, s = Gensquares[]; While[c < s, c = Gencubes[]; ]; If[s =!= c, Break[] ]; ]; If[i > 20, Print[s] ] , {i, 30} ]
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#REXX
REXX
/*REXX program generates a random starting position for the Chess960 game. */ parse arg seed . /*allow for (RANDOM BIF) repeatability.*/ if seed\=='' then call random ,,seed /*if SEED was specified, use the seed.*/ @.=. /*define the first rank as being empty.*/ r1=random(1,6) /*generate the first rook: rank 1. */ @.r1='R' /*place the first rook on rank1. */ do until r2\==r1 & r2\==r1-1 & r2\==r1+1 r2=random(1,8) /*find placement for the 2nd rook. */ end /*forever*/ @.r2='r' /*place the second rook on rank 1. */ k=random(min(r1, r2)+1, max(r1, r2)-1) /*find a random position for the king. */ @.k='K' /*place king between the two rooks. */ do _=0  ; b1=random(1,8); if @.b1\==. then iterate; c=b1//2 do forever; b2=random(1,8) /* c=color of bishop ►──┘ */ if @.b2\==. | b2==b1 | b2//2==c then iterate /*is a bad position?*/ leave _ /*found position for the 2 clergy*/ end /*forever*/ /* [↑] find a place for the 1st bishop*/ end /* _ */ /* [↑] " " " " " 2nd " */ @.b1='B' /*place the 1st bishop on rank 1. */ @.b2='b' /* " " 2nd " " " " */ /*place the two knights on rank 1. */ do until @._='N'; _=random(1,8); if @._\==. then iterate; @._='N'; end do until @.!='n';  !=random(1,8); if @.!\==. then iterate; @.!='n'; end _= /*only the queen is left to be placed. */ do i=1 for 8; _=_ || @.i; end /*construct the output: first rank only*/ say translate(translate(_, 'q', .)) /*stick a fork in it, we're all done. */
http://rosettacode.org/wiki/Function_composition
Function composition
Task Create a function, compose,   whose two arguments   f   and   g,   are both functions with one argument. The result of compose is to be a function of one argument, (lets call the argument   x),   which works like applying function   f   to the result of applying function   g   to   x. Example compose(f, g) (x) = f(g(x)) Reference: Function composition Hint: In some languages, implementing compose correctly requires creating a closure.
#Arturo
Arturo
compose: function [f,g] -> return function [x].import:[f,g][ call f @[call g @[x]] ]   splitupper: compose 'split 'upper   print call 'splitupper ["done"]
http://rosettacode.org/wiki/Function_composition
Function composition
Task Create a function, compose,   whose two arguments   f   and   g,   are both functions with one argument. The result of compose is to be a function of one argument, (lets call the argument   x),   which works like applying function   f   to the result of applying function   g   to   x. Example compose(f, g) (x) = f(g(x)) Reference: Function composition Hint: In some languages, implementing compose correctly requires creating a closure.
#ATS
ATS
(* The task:   Create a function, compose, whose two arguments f and g, are both functions with one argument.   The result of compose is to be a function of one argument, (let's call the argument x), which works like applying function f to the result of applying function g to x.   In ATS, we have to choose whether to use non-linear closures (cloref) or linear closures (cloptr). In the latter case, we also have to choose between closures allocated with malloc (or similar) and closures allocated on the stack.   For simplicity, we will use non-linear closures and assume there is a garbage collector, or that the memory allocated for the closures can be allowed to leak. (This is often the case in a program that does not run continuously.) *)   #include "share/atspre_staload.hats"   (* The following is actually a *template function*, rather than a function proper. It is expanded during template processing. *)   fn {t1, t2, t3 : t@ype} compose (f : t2 -<cloref1> t3, g : t1 -<cloref1> t2) : t1 -<cloref1> t3 = lam x => f (g (x))     implement main0 () = let val one_hundred = 100.0 val char_zero = '0' val f = (lam y =<cloref1> add_double_int (one_hundred, y)) val g = (lam x =<cloref1> char2i x - char2i char_zero) val z = compose (f, g) ('5') val fg = compose (f, g) val w = fg ('7') in println! (z : double); println! (w : double) end
http://rosettacode.org/wiki/Fractal_tree
Fractal tree
Generate and draw a fractal tree. Draw the trunk At the end of the trunk, split by some angle and draw two branches Repeat at the end of each branch until a sufficient level of branching is reached Related tasks Pythagoras Tree
#11l
11l
-V Width = 1000 Height = 1000 TrunkLength = 400 ScaleFactor = 0.6 StartingAngle = 1.5 * math:pi DeltaAngle = 0.2 * math:pi   F drawTree(outfile, Float x, Float y; len, theta) -> N I len >= 1 V x2 = x + len * cos(theta) V y2 = y + len * sin(theta) outfile.write("<line x1='#.6' y1='#.6' x2='#.6' y2='#.6' style='stroke:white;stroke-width:1'/>\n".format(x, y, x2, y2)) drawTree(outfile, x2, y2, len * ScaleFactor, theta + DeltaAngle) drawTree(outfile, x2, y2, len * ScaleFactor, theta - DeltaAngle)   V outsvg = File(‘tree.svg’, ‘w’) outsvg.write(|‘<?xml version='1.0' encoding='utf-8' standalone='no'?> <!DOCTYPE svg PUBLIC '-//W3C//DTD SVG 1.1//EN' 'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'> <svg width='100%%' height='100%%' version='1.1' xmlns='http://www.w3.org/2000/svg'> <rect width="100%" height="100%" fill="black"/> ’) drawTree(outsvg, 0.5 * Width, Height, TrunkLength, StartingAngle) outsvg.write("</svg>\n")
http://rosettacode.org/wiki/Fractran
Fractran
FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Horton Conway. A FRACTRAN program is an ordered list of positive fractions P = ( f 1 , f 2 , … , f m ) {\displaystyle P=(f_{1},f_{2},\ldots ,f_{m})} , together with an initial positive integer input n {\displaystyle n} . The program is run by updating the integer n {\displaystyle n} as follows: for the first fraction, f i {\displaystyle f_{i}} , in the list for which n f i {\displaystyle nf_{i}} is an integer, replace n {\displaystyle n} with n f i {\displaystyle nf_{i}}  ; repeat this rule until no fraction in the list produces an integer when multiplied by n {\displaystyle n} , then halt. Conway gave a program for primes in FRACTRAN: 17 / 91 {\displaystyle 17/91} , 78 / 85 {\displaystyle 78/85} , 19 / 51 {\displaystyle 19/51} , 23 / 38 {\displaystyle 23/38} , 29 / 33 {\displaystyle 29/33} , 77 / 29 {\displaystyle 77/29} , 95 / 23 {\displaystyle 95/23} , 77 / 19 {\displaystyle 77/19} , 1 / 17 {\displaystyle 1/17} , 11 / 13 {\displaystyle 11/13} , 13 / 11 {\displaystyle 13/11} , 15 / 14 {\displaystyle 15/14} , 15 / 2 {\displaystyle 15/2} , 55 / 1 {\displaystyle 55/1} Starting with n = 2 {\displaystyle n=2} , this FRACTRAN program will change n {\displaystyle n} to 15 = 2 × ( 15 / 2 ) {\displaystyle 15=2\times (15/2)} , then 825 = 15 × ( 55 / 1 ) {\displaystyle 825=15\times (55/1)} , generating the following sequence of integers: 2 {\displaystyle 2} , 15 {\displaystyle 15} , 825 {\displaystyle 825} , 725 {\displaystyle 725} , 1925 {\displaystyle 1925} , 2275 {\displaystyle 2275} , 425 {\displaystyle 425} , 390 {\displaystyle 390} , 330 {\displaystyle 330} , 290 {\displaystyle 290} , 770 {\displaystyle 770} , … {\displaystyle \ldots } After 2, this sequence contains the following powers of 2: 2 2 = 4 {\displaystyle 2^{2}=4} , 2 3 = 8 {\displaystyle 2^{3}=8} , 2 5 = 32 {\displaystyle 2^{5}=32} , 2 7 = 128 {\displaystyle 2^{7}=128} , 2 11 = 2048 {\displaystyle 2^{11}=2048} , 2 13 = 8192 {\displaystyle 2^{13}=8192} , 2 17 = 131072 {\displaystyle 2^{17}=131072} , 2 19 = 524288 {\displaystyle 2^{19}=524288} , … {\displaystyle \ldots } which are the prime powers of 2. Task Write a program that reads a list of fractions in a natural format from the keyboard or from a string, to parse it into a sequence of fractions (i.e. two integers), and runs the FRACTRAN starting from a provided integer, writing the result at each step. It is also required that the number of steps is limited (by a parameter easy to find). Extra credit Use this program to derive the first 20 or so prime numbers. See also For more on how to program FRACTRAN as a universal programming language, see: J. H. Conway (1987). Fractran: A Simple Universal Programming Language for Arithmetic. In: Open Problems in Communication and Computation, pages 4–26. Springer. J. H. Conway (2010). "FRACTRAN: A simple universal programming language for arithmetic". In Jeffrey C. Lagarias. The Ultimate Challenge: the 3x+1 problem. American Mathematical Society. pp. 249–264. ISBN 978-0-8218-4940-8. Zbl 1216.68068. Number Pathology: Fractran by Mark C. Chu-Carroll; October 27, 2006.
#Ada
Ada
with Ada.Text_IO;   procedure Fractan is   type Fraction is record Nom: Natural; Denom: Positive; end record; type Frac_Arr is array(Positive range <>) of Fraction;   function "/" (N: Natural; D: Positive) return Fraction is Frac: Fraction := (Nom => N, Denom => D); begin return Frac; end "/";   procedure F(List: Frac_Arr; Start: Positive; Max_Steps: Natural) is N: Positive := Start; J: Positive; begin Ada.Text_IO.Put(" 0:" & Integer'Image(N) & " "); for I in 1 .. Max_Steps loop J := List'First; loop if N mod List(J).Denom = 0 then N := (N/List(J).Denom) * List(J).Nom; exit; -- found fraction elsif J >= List'Last then return; -- did try out all fractions else J := J + 1; -- try the next fraction end if; end loop; Ada.Text_IO.Put(Integer'Image(I) & ":" & Integer'Image(N) & " "); end loop; end F;   begin -- F((2/3, 7/2, 1/5, 1/7, 1/9, 1/4, 1/8), 2, 100); -- output would be "0: 2 1: 7 2: 1" and then terminate   F((17/91, 78/85, 19/51, 23/38, 29/33, 77/29, 95/23, 77/19, 1/17, 11/13, 13/11, 15/14, 15/2, 55/1), 2, 15); -- output is "0: 2 1: 15 2: 825 3: 725 ... 14: 132 15: 116" end Fractan;
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Java
Java
import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import org.apache.commons.net.ftp.FTP; import org.apache.commons.net.ftp.FTPClient; import org.apache.commons.net.ftp.FTPFile; import org.apache.commons.net.ftp.FTPReply;   public class FTPconn {   public static void main(String[] args) throws IOException { String server = "ftp.hq.nasa.gov"; int port = 21; String user = "anonymous"; String pass = "[email protected]";   OutputStream output = null;   FTPClient ftpClient = new FTPClient(); try { ftpClient.connect(server, port);   serverReply(ftpClient);   int replyCode = ftpClient.getReplyCode(); if (!FTPReply.isPositiveCompletion(replyCode)) { System.out.println("Failure. Server reply code: " + replyCode); return; }   serverReply(ftpClient);   if (!ftpClient.login(user, pass)) { System.out.println("Could not login to the server."); return; }   String dir = "pub/issoutreach/Living in Space Stories (MP3 Files)/"; if (!ftpClient.changeWorkingDirectory(dir)) { System.out.println("Change directory failed."); return; }   ftpClient.enterLocalPassiveMode();   for (FTPFile file : ftpClient.listFiles()) System.out.println(file);   String filename = "Can People go to Mars.mp3"; output = new FileOutputStream(filename);   ftpClient.setFileType(FTP.BINARY_FILE_TYPE); if (!ftpClient.retrieveFile(filename, output)) { System.out.println("Retrieving file failed"); return; }   serverReply(ftpClient);   ftpClient.logout();   } finally { if (output != null) output.close(); } }   private static void serverReply(FTPClient ftpClient) { for (String reply : ftpClient.getReplyStrings()) { System.out.println(reply); } } }
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Oforth
Oforth
Method new: myMethod
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Ol
Ol
  'DECLARE FUNCTION' ABBREVIATED TO '!'   ! f() ' a procedure with no params ! f(int a) ' with 1 int param ! f(int *a) ' with 1 int pointer param ! f(int a, int b, inc c) ' with 3 int params ! f(int a,b,c) ' compaction with 3 int params ! f(string s, int a,b) ' with 1 string and 2 int params ! f() as string ' function returning a string ! f(string s) as string ' with 1 string param ! *f(string s) as string ' as a function pointer: @f=address ! f(string s, optional i) ' with opptional param ! f(string s = "Hello") ' optional param with default value ! f(int n, ...) ' 1 specific param and varargs ! f(...) ' any params or none   'TRADITIONAL BASIC DECLARATIONS declare sub f( s as string, i as long, j as long) ' byref by default declare function f( byref s as string, byval i as long, byval j as long) as string   'C-STYLE DECLARATIONS void f(string *s, long i, long j) string f(string *s, long i, long j)       'BLOCK DIRECTIVES FOR FUNCTION PROTOTYPES:   extern ' shareable stdcall functions   extern lib "xyz.dll" ' for accessing functions in xyz Dynamic Link Library   extern export ' functions to be exported if this is a DLL   extern virtual ' for accssing interfaces and other virtual classes   end extern ' revert to internal function mode    
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#OxygenBasic
OxygenBasic
  'DECLARE FUNCTION' ABBREVIATED TO '!'   ! f() ' a procedure with no params ! f(int a) ' with 1 int param ! f(int *a) ' with 1 int pointer param ! f(int a, int b, inc c) ' with 3 int params ! f(int a,b,c) ' compaction with 3 int params ! f(string s, int a,b) ' with 1 string and 2 int params ! f() as string ' function returning a string ! f(string s) as string ' with 1 string param ! *f(string s) as string ' as a function pointer: @f=address ! f(string s, optional i) ' with opptional param ! f(string s = "Hello") ' optional param with default value ! f(int n, ...) ' 1 specific param and varargs ! f(...) ' any params or none   'TRADITIONAL BASIC DECLARATIONS declare sub f( s as string, i as long, j as long) ' byref by default declare function f( byref s as string, byval i as long, byval j as long) as string   'C-STYLE DECLARATIONS void f(string *s, long i, long j) string f(string *s, long i, long j)       'BLOCK DIRECTIVES FOR FUNCTION PROTOTYPES:   extern ' shareable stdcall functions   extern lib "xyz.dll" ' for accessing functions in xyz Dynamic Link Library   extern export ' functions to be exported if this is a DLL   extern virtual ' for accssing interfaces and other virtual classes   end extern ' revert to internal function mode    
http://rosettacode.org/wiki/Function_definition
Function definition
A function is a body of code that returns a value. The value returned may depend on arguments provided to the function. Task Write a definition of a function called "multiply" that takes two arguments and returns their product. (Argument types should be chosen so as not to distract from showing how functions are created and values returned). Related task   Function prototype
#8086_Assembly
8086 Assembly
start: mov al, 0x04 mov bl, 0x05 call multiply ;at this point in execution, the AX register contains 0x0900. ;more code goes here, ideally with some sort of guard against "fallthrough" into multiply.   ; somewhere far away from start multiply: mul bl ;outputs 0x0014 to ax ret
http://rosettacode.org/wiki/French_Republican_calendar
French Republican calendar
Write a program to convert dates between the Gregorian calendar and the French Republican calendar. The year 1 of the Republican calendar began on 22 September 1792. There were twelve months (Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor) of 30 days each, followed by five intercalary days or Sansculottides (Fête de la vertu / Virtue Day, Fête du génie / Talent Day, Fête du travail / Labour Day, Fête de l'opinion / Opinion Day, and Fête des récompenses / Honours Day). In leap years (the years 3, 7, and 11) a sixth Sansculottide was added: Fête de la Révolution / Revolution Day. As a minimum, your program should give correct results for dates in the range from 1 Vendémiaire 1 = 22 September 1792 to 10 Nivôse 14 = 31 December 1805 (the last day when the Republican calendar was officially in use). If you choose to accept later dates, be aware that there are several different methods (described on the Wikipedia page) about how to determine leap years after the year 14. You should indicate which method you are using. (Because of these different methods, correct programs may sometimes give different results for dates after 1805.) Test your program by converting the following dates both from Gregorian to Republican and from Republican to Gregorian: • 1 Vendémiaire 1 = 22 September 1792 • 1 Prairial 3 = 20 May 1795 • 27 Messidor 7 = 15 July 1799 (Rosetta Stone discovered) • Fête de la Révolution 11 = 23 September 1803 • 10 Nivôse 14 = 31 December 1805
#Nim
Nim
  import strformat, strscans, strutils, times   const   RcMonths = ["Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse", "Ventôse", "Germinal", "Floréal", "Prairial", "Messidor", "Thermidor", "Fructidor"]   SansCulottides = ["Fête de la vertu", "Fête du génie", "Fête du travail", "Fête de l’opinion", "Fête des récompenses", "Fête de la Révolution"]   let # First and last dates of republican calendar expressed in gregorian calendar. FirstRcDate = initDateTime(22, mSep, 1792, 0, 0, 0) LastRcDate = initDateTime(31, mDec, 1805, 0, 0, 0)   type # French republican date representation. RcDayRange = 1..30 RcMonthRange = 1..13 RcYearRange = 1..14 RepublicanDate = tuple[year: RcYearRange, month: RcMonthRange, day: RcDayRange]   # Last dates of republican calendar expressed in republican calendar. const RcLastDate: RepublicanDate = (RcYearRange(14), RcMonthRange(4), RcDayRange(10))     proc notnum(input: string; str: var string; start: int): int = # Parsing procedure to extract non numerical part of a date. var i = start while i <= input.high: if input[i] in '0'..'9': break str.add input[i] inc i if str.len == 0 or str[^1] != ' ': return -1 # Not terminated by a space. str.setLen(str.len - 1) # Back before the space. result = str.len     proc parseRepublicanDate(rdate: string): RepublicanDate = ## Parse a French republican date and return its representation.   let date = rdate.strip() var day, month, year: int var monthString, dayString: string   if date.scanf("$i $+ $i", day, monthString, year): # Normal day. if day notin 1..30: raise newException(ValueError, "wrong day number: $1.".format(day)) month = RcMonths.find(monthString) + 1 if month == 0: raise newException(ValueError, "unknown French republican month: $1." % monthString)   elif date.scanf("${notnum} $i", dayString, year): # Sans-culottide day (also known as “jour complémentaire”). month = 13 # Value used for sans-culottide days. day = SansCulottides.find(dayString) + 1 if day == 0: raise newException(ValueError, "wrong “sans-culottide” day: « $1 »." % dayString) if day == 6 and year mod 4 != 3: raise newException(ValueError, "republican year $1 is not a leap year".format(year))   else: raise newException(ValueError, "invalid French republican date: « $1 »." % date)   result = (RcYearRange(year), RcMonthRange(month), RcDayRange(day)) if result > RcLastDate: raise newException(ValueError, "republican date out of range: « $1 »." % date)     proc `$`(date: RepublicanDate): string = ## Return the string representation of a French republican date.   if date.month != 13: # Normal day. result = "$1 $2 $3".format(date.day, RcMonths[date.month - 1], date.year) else: # Supplementary day. result = "$1 $2".format(SansCulottides[date.day - 1], date.year)     proc toGregorian(rdate: RepublicanDate): DateTime = ## Convert a republican date tuple to a gregorian date (DateTime object). let day = (rdate.day - 1) + (rdate.month - 1) * 30 + (rdate.year - 1) * 365 + rdate.year div 4 result = FirstRcDate + initTimeInterval(days = day)     proc toGregorian(rdate: string): string = ## Convert a republican date string to a gregorian date string. let date = rdate.parseRepublicanDate() result = date.toGregorian().format("dd MMMM yyyy")     proc toRepublican(gdate: DateTime): RepublicanDate = ## Convert a gregorian date (DateTime object) to a republican date tuple.   if gdate notin FirstRcDate..LastRcDate: raise newException(ValueError, "impossible conversion to republican date.") let d = gdate - FirstRcDate   # Add a dummy year before year 1 in order to use a four years period. let dayNumber = d.inDays + 365 let periodNum = dayNumber div 1461 let dayInPeriod = dayNumber mod 1461   # Compute year and day in year. let yearInPeriod = min(dayInPeriod div 365, 3) result.year = periodNum * 4 + yearInPeriod let dayInYear = dayInPeriod - yearInPeriod * 365   # Compute month and day. result.month = dayInYear div 30 + 1 result.day = dayInYear mod 30 + 1     proc toRepublican(gdate: string): string = ## Convert a gregorian date string to a republican date string. let date = gdate.parse("d MMMM yyyy") result = $(date.toRepublican())     when isMainModule:   const RepublicanDates = ["1 Vendémiaire 1", "1 Prairial 3", "27 Messidor 7", "Fête de la Révolution 11", "10 Nivôse 14"] GregorianDates = ["22 September 1792", "20 May 1795", "15 July 1799", "23 September 1803", "31 December 1805"]   echo "From French republican dates to gregorian dates:" for rdate in RepublicanDates: echo &"{rdate:>24} → {rdate.toGregorian()}" echo()   echo "From gregorian dates to French republican dates:" for gdate in GregorianDates: echo &"{gdate:>24} → {gdate.toRepublican()}"
http://rosettacode.org/wiki/French_Republican_calendar
French Republican calendar
Write a program to convert dates between the Gregorian calendar and the French Republican calendar. The year 1 of the Republican calendar began on 22 September 1792. There were twelve months (Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor) of 30 days each, followed by five intercalary days or Sansculottides (Fête de la vertu / Virtue Day, Fête du génie / Talent Day, Fête du travail / Labour Day, Fête de l'opinion / Opinion Day, and Fête des récompenses / Honours Day). In leap years (the years 3, 7, and 11) a sixth Sansculottide was added: Fête de la Révolution / Revolution Day. As a minimum, your program should give correct results for dates in the range from 1 Vendémiaire 1 = 22 September 1792 to 10 Nivôse 14 = 31 December 1805 (the last day when the Republican calendar was officially in use). If you choose to accept later dates, be aware that there are several different methods (described on the Wikipedia page) about how to determine leap years after the year 14. You should indicate which method you are using. (Because of these different methods, correct programs may sometimes give different results for dates after 1805.) Test your program by converting the following dates both from Gregorian to Republican and from Republican to Gregorian: • 1 Vendémiaire 1 = 22 September 1792 • 1 Prairial 3 = 20 May 1795 • 27 Messidor 7 = 15 July 1799 (Rosetta Stone discovered) • Fête de la Révolution 11 = 23 September 1803 • 10 Nivôse 14 = 31 December 1805
#Perl
Perl
use feature 'state'; use DateTime; my @month_names = qw{ Vendémiaire Brumaire Frimaire Nivôse Pluviôse Ventôse Germinal Floréal Prairial Messidor Thermidor Fructidor }; my @intercalary = ( 'Fête de la vertu', 'Fête du génie', 'Fête du travail', "Fête de l'opinion", 'Fête des récompenses', 'Fête de la Révolution', ); my %month_nums = map { $month_names[$_] => $_+1 } 0 .. $#month_names; my %i_cal_nums = map { $intercalary[$_] => $_+1 } 0 .. $#intercalary; my $i_cal_month = 13; my $epoch = DateTime->new( year => 1792, month => 9, day => 22 );   sub is_republican_leap_year { my $y = $_[0] + 1; return !!( ($y % 4)==0 and (($y % 100)!=0 or ($y % 400)==0) ); }   sub Republican_to_Gregorian { my ($rep_date) = @_; state $months = join '|', map { quotemeta } @month_names; state $intercal = join '|', map { quotemeta } @intercalary; state $re = qr{ \A \s* (?: (?<ic> $intercal) | (?<day> \d+) \s+ (?<month> $months) ) \s+ (?<year> \d+) \s* \z }msx;   $rep_date =~ /$re/ or die "Republican date not recognized: '$rep_date'";   my $day1 = $+{ic} ? $i_cal_nums{$+{ic}} : $+{day}; my $month1 = $+{month} ? $month_nums{$+{month}} : $i_cal_month; my $year1 = $+{year};   my $days_since_epoch = ($year1-1) * 365 + ($month1-1) * 30 + ($day1-1);   my $leap_days = grep { is_republican_leap_year($_) } 1 .. $year1-1; return $epoch->clone->add( days => ($days_since_epoch + $leap_days) ); }   sub Gregorian_to_Republican { my ($greg_date) = @_;   my $days_since_epoch = $epoch->delta_days($greg_date)->in_units('days'); die if $days_since_epoch < 0; my ( $year, $days ) = ( 1, $days_since_epoch ); while (1) { my $year_length = 365 + ( is_republican_leap_year($year) ? 1 : 0 ); last if $days < $year_length; $days -= $year_length; $year += 1; } my $day0 = $days % 30; my $month0 = ($days - $day0) / 30;   my ( $day1, $month1 ) = ( $day0 + 1, $month0 + 1 );   return $month1 == $i_cal_month ? "$intercalary[$day0 ] $year" : "$day1 $month_names[$month0] $year"; }   while (<DATA>) { s{\s*\#.+\n?\z}{}; /^(\d{4})-(\d{2})-(\d{2})\s+(\S.+?\S)\s*$/ or die;   my $g = DateTime->new( year => $1, month => $2, day => $3 ); my $r = $4;   die if Republican_to_Gregorian($r) != $g or Gregorian_to_Republican($g) ne $r;   die if Gregorian_to_Republican(Republican_to_Gregorian($r)) ne $r or Republican_to_Gregorian(Gregorian_to_Republican($g)) != $g; } say 'All tests successful.';   __DATA__ 1792-09-22 1 Vendémiaire 1 1795-05-20 1 Prairial 3 1799-07-15 27 Messidor 7 1803-09-23 Fête de la Révolution 11 1805-12-31 10 Nivôse 14 1871-03-18 27 Ventôse 79 1944-08-25 7 Fructidor 152 2016-09-19 Fête du travail 224 1871-05-06 16 Floréal 79 # Paris Commune begins 1871-05-23 3 Prairial 79 # Paris Commune ends 1799-11-09 18 Brumaire 8 # Revolution ends by Napoléon coup 1804-12-02 11 Frimaire 13 # Republic ends by Napoléon coronation 1794-10-30 9 Brumaire 3 # École Normale Supérieure established 1794-07-27 9 Thermidor 2 # Robespierre falls 1799-05-27 8 Prairial 7 # Fromental Halévy born 1792-09-22 1 Vendémiaire 1 1793-09-22 1 Vendémiaire 2 1794-09-22 1 Vendémiaire 3 1795-09-23 1 Vendémiaire 4 1796-09-22 1 Vendémiaire 5 1797-09-22 1 Vendémiaire 6 1798-09-22 1 Vendémiaire 7 1799-09-23 1 Vendémiaire 8 1800-09-23 1 Vendémiaire 9 1801-09-23 1 Vendémiaire 10 1802-09-23 1 Vendémiaire 11 1803-09-24 1 Vendémiaire 12 1804-09-23 1 Vendémiaire 13 1805-09-23 1 Vendémiaire 14 1806-09-23 1 Vendémiaire 15 1807-09-24 1 Vendémiaire 16 1808-09-23 1 Vendémiaire 17 1809-09-23 1 Vendémiaire 18 1810-09-23 1 Vendémiaire 19 1811-09-24 1 Vendémiaire 20 2015-09-23 1 Vendémiaire 224 2016-09-22 1 Vendémiaire 225 2017-09-22 1 Vendémiaire 226  
http://rosettacode.org/wiki/Fusc_sequence
Fusc sequence
Definitions The   fusc   integer sequence is defined as:   fusc(0) = 0   fusc(1) = 1   for n>1,   the   nth   term is defined as:   if   n   is even;     fusc(n) = fusc(n/2)   if   n   is   odd;     fusc(n) = fusc((n-1)/2)   +   fusc((n+1)/2) Note that MathWorld's definition starts with unity, not zero.   This task will be using the OEIS' version   (above). An observation   fusc(A) = fusc(B) where   A   is some non-negative integer expressed in binary,   and where   B   is the binary value of   A   reversed. Fusc numbers are also known as:   fusc function   (named by Dijkstra, 1982)   Stern's Diatomic series   (although it starts with unity, not zero)   Stern-Brocot sequence   (although it starts with unity, not zero) Task   show the first   61   fusc numbers (starting at zero) in a horizontal format.   show the fusc number (and its index) whose length is greater than any previous fusc number length.   (the length is the number of decimal digits when the fusc number is expressed in base ten.)   show all numbers with commas   (if appropriate).   show all output here. Related task   RosettaCode Stern-Brocot sequence Also see   the MathWorld entry:   Stern's Diatomic Series.   the OEIS entry:   A2487.
#C.23
C#
using System; using System.Collections.Generic;   static class program { static int n = 61; static List<int> l = new List<int>() { 0, 1 };   static int fusc(int n) { if (n < l.Count) return l[n]; int f = (n & 1) == 0 ? l[n >> 1] : l[(n - 1) >> 1] + l[(n + 1) >> 1]; l.Add(f); return f; }   static void Main(string[] args) { bool lst = true; int w = -1, c = 0, t; string fs = "{0,11:n0} {1,-9:n0}", res = ""; Console.WriteLine("First {0} numbers in the fusc sequence:", n); for (int i = 0; i < int.MaxValue; i++) { int f = fusc(i); if (lst) { if (i < 61) Console.Write("{0} ", f); else { lst = false; Console.WriteLine(); Console.WriteLine("Points in the sequence where an item has more digits than any previous items:"); Console.WriteLine(fs, "Index\\", "/Value"); Console.WriteLine(res); res = ""; } } if ((t = f.ToString().Length) > w) { w = t; res += (res == "" ? "" : "\n") + string.Format(fs, i, f); if (!lst) { Console.WriteLine(res); res = ""; } if (++c > 5) break; } } l.Clear(); } }
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Nim
Nim
# naive function calling counter # TODO consider a more sophisticated condition on counting function callings # without parenthesis which are common in nim lang. Be aware that the AST of # object accessor and procedure calling without parenthesis are same.   import macros, tables, strformat, os proc visitCall(node: NimNode, table: CountTableRef) = if node.kind == nnkCall: if node[0].kind == nnkDotExpr: table.inc($node[0][1]) visitCall(node[0][0], table) else: if node[0].kind == nnkBracketExpr: if node[0][0].kind == nnkDotExpr: table.inc($node[0][0][1]) visitCall(node[0][0][0], table) return else: table.inc($node[0][0]) if len(node[0]) > 1: for child in node[0][1..^1]: visitCall(child, table) elif node[0].kind == nnkPar: visitCall(node[0], table) else: table.inc($node[0]) if len(node) > 1: for child in node[1..^1]: visitCall(child, table) else: for child in node.children(): visitCall(child, table)   static: const code = staticRead(expandTilde(&"~/.choosenim/toolchains/nim-{NimVersion}/lib/system.nim")) var ast = parseStmt(code) callCounts = newCountTable[string]() ast.visitCall(callCounts) sort(callCounts) var total = 10 for ident, times in callCounts.pairs(): echo(&"{ident} called {times} times") total-=1 if total == 0: break
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Perl
Perl
use PPI::Tokenizer; my $Tokenizer = PPI::Tokenizer->new( '/path/to/your/script.pl' ); my %counts; while (my $token = $Tokenizer->get_token) { # We consider all Perl identifiers. The following regex is close enough. if ($token =~ /\A[\$\@\%*[:alpha:]]/) { $counts{$token}++; } } my @desc_by_occurrence = sort {$counts{$b} <=> $counts{$a} || $a cmp $b} keys(%counts); my @top_ten_by_occurrence = @desc_by_occurrence[0 .. 9]; foreach my $token (@top_ten_by_occurrence) { print $counts{$token}, "\t", $token, "\n"; }
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#C.2B.2B
C++
#include <math.h> #include <numbers> #include <stdio.h> #include <vector>   // Calculate the coefficients used by Spouge's approximation (based on the C // implemetation) std::vector<double> CalculateCoefficients(int numCoeff) { std::vector<double> c(numCoeff); double k1_factrl = 1.0; c[0] = sqrt(2.0 * std::numbers::pi); for(size_t k=1; k < numCoeff; k++) { c[k] = exp(numCoeff-k) * pow(numCoeff-k, k-0.5) / k1_factrl; k1_factrl *= -(double)k; } return c; }   // The Spouge approximation double Gamma(const std::vector<double>& coeffs, double x) { const size_t numCoeff = coeffs.size(); double accm = coeffs[0]; for(size_t k=1; k < numCoeff; k++) { accm += coeffs[k] / ( x + k ); } accm *= exp(-(x+numCoeff)) * pow(x+numCoeff, x+0.5); return accm/x; }   int main() { // estimate the gamma function with 1, 4, and 10 coefficients const auto coeff1 = CalculateCoefficients(1); const auto coeff4 = CalculateCoefficients(4); const auto coeff10 = CalculateCoefficients(10);   const auto inputs = std::vector<double>{ 0.001, 0.01, 0.1, 0.5, 1.0, 1.461632145, // minimum of the gamma function 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 150 // causes overflow for this implemetation };   printf("%16s%16s%16s%16s%16s\n", "gamma( x ) =", "Spouge 1", "Spouge 4", "Spouge 10", "built-in"); for(auto x : inputs) { printf("gamma(%7.3f) = %16.10g %16.10g %16.10g %16.10g\n", x, Gamma(coeff1, x), Gamma(coeff4, x), Gamma(coeff10, x), std::tgamma(x)); // built-in gamma function } }  
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#Java
Java
import java.util.Random; import java.util.List; import java.util.ArrayList;   public class GaltonBox { public static void main( final String[] args ) { new GaltonBox( 8, 200 ).run(); }   private final int m_pinRows; private final int m_startRow; private final Position[] m_balls; private final Random m_random = new Random();   public GaltonBox( final int pinRows, final int ballCount ) { m_pinRows = pinRows; m_startRow = pinRows + 1; m_balls = new Position[ ballCount ];   for ( int ball = 0; ball < ballCount; ball++ ) m_balls[ ball ] = new Position( m_startRow, 0, 'o' ); }   private static class Position { int m_row; int m_col; char m_char;   Position( final int row, final int col, final char ch ) { m_row = row; m_col = col; m_char = ch; } }   public void run() { for ( int ballsInPlay = m_balls.length; ballsInPlay > 0; ) { ballsInPlay = dropBalls(); print(); } }   private int dropBalls() { int ballsInPlay = 0; int ballToStart = -1;   // Pick a ball to start dropping for ( int ball = 0; ball < m_balls.length; ball++ ) if ( m_balls[ ball ].m_row == m_startRow ) ballToStart = ball;   // Drop balls that are already in play for ( int ball = 0; ball < m_balls.length; ball++ ) if ( ball == ballToStart ) { m_balls[ ball ].m_row = m_pinRows; ballsInPlay++; } else if ( m_balls[ ball ].m_row > 0 && m_balls[ ball ].m_row != m_startRow ) { m_balls[ ball ].m_row -= 1; m_balls[ ball ].m_col += m_random.nextInt( 2 ); if ( 0 != m_balls[ ball ].m_row ) ballsInPlay++; }   return ballsInPlay; }   private void print() { for ( int row = m_startRow; row --> 1; ) { for ( int ball = 0; ball < m_balls.length; ball++ ) if ( m_balls[ ball ].m_row == row ) printBall( m_balls[ ball ] ); System.out.println(); printPins( row ); } printCollectors(); System.out.println(); }   private static void printBall( final Position pos ) { for ( int col = pos.m_row + 1; col --> 0; ) System.out.print( ' ' ); for ( int col = 0; col < pos.m_col; col++ ) System.out.print( " " ); System.out.print( pos.m_char ); }   private void printPins( final int row ) { for ( int col = row + 1; col --> 0; ) System.out.print( ' ' ); for ( int col = m_startRow - row; col --> 0; ) System.out.print( ". " ); System.out.println(); }   private void printCollectors() { final List<List<Position>> collectors = new ArrayList<List<Position>>();   for ( int col = 0; col < m_startRow; col++ ) { final List<Position> collector = new ArrayList<Position>();   collectors.add( collector ); for ( int ball = 0; ball < m_balls.length; ball++ ) if ( m_balls[ ball ].m_row == 0 && m_balls[ ball ].m_col == col ) collector.add( m_balls[ ball ] ); }   for ( int row = 0, rows = longest( collectors ); row < rows; row++ ) { for ( int col = 0; col < m_startRow; col++ ) { final List<Position> collector = collectors.get( col ); final int pos = row + collector.size() - rows;   System.out.print( '|' ); if ( pos >= 0 ) System.out.print( collector.get( pos ).m_char ); else System.out.print( ' ' ); } System.out.println( '|' ); } }   private static final int longest( final List<List<Position>> collectors ) { int result = 0;   for ( final List<Position> collector : collectors ) result = Math.max( collector.size(), result );   return result; } }
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Haskell
Haskell
{-# LANGUAGE NumericUnderscores #-}   gapful :: Int -> Bool gapful n = n `rem` firstLastDigit == 0 where firstLastDigit = read [head asDigits, last asDigits] asDigits = show n   main :: IO () main = do putStrLn $ "\nFirst 30 Gapful numbers >= 100 :\n" ++ r 30 [100,101..] putStrLn $ "\nFirst 15 Gapful numbers >= 1,000,000 :\n" ++ r 15 [1_000_000,1_000_001..] putStrLn $ "\nFirst 10 Gapful numbers >= 1,000,000,000 :\n" ++ r 10 [1_000_000_000,1_000_000_001..] where r n = show . take n . filter gapful
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#Java
Java
import java.util.Locale;   public class GaussianElimination { public static double solve(double[][] a, double[][] b) { if (a == null || b == null || a.length == 0 || b.length == 0) { throw new IllegalArgumentException("Invalid dimensions"); }   int n = b.length, p = b[0].length; if (a.length != n || a[0].length != n) { throw new IllegalArgumentException("Invalid dimensions"); }   double det = 1.0;   for (int i = 0; i < n - 1; i++) { int k = i; for (int j = i + 1; j < n; j++) { if (Math.abs(a[j][i]) > Math.abs(a[k][i])) { k = j; } }   if (k != i) { det = -det;   for (int j = i; j < n; j++) { double s = a[i][j]; a[i][j] = a[k][j]; a[k][j] = s; }   for (int j = 0; j < p; j++) { double s = b[i][j]; b[i][j] = b[k][j]; b[k][j] = s; } }   for (int j = i + 1; j < n; j++) { double s = a[j][i] / a[i][i]; for (k = i + 1; k < n; k++) { a[j][k] -= s * a[i][k]; }   for (k = 0; k < p; k++) { b[j][k] -= s * b[i][k]; } } }   for (int i = n - 1; i >= 0; i--) { for (int j = i + 1; j < n; j++) { double s = a[i][j]; for (int k = 0; k < p; k++) { b[i][k] -= s * b[j][k]; } } double s = a[i][i]; det *= s; for (int k = 0; k < p; k++) { b[i][k] /= s; } }   return det; }   public static void main(String[] args) { double[][] a = new double[][] {{4.0, 1.0, 0.0, 0.0, 0.0}, {1.0, 4.0, 1.0, 0.0, 0.0}, {0.0, 1.0, 4.0, 1.0, 0.0}, {0.0, 0.0, 1.0, 4.0, 1.0}, {0.0, 0.0, 0.0, 1.0, 4.0}};   double[][] b = new double[][] {{1.0 / 2.0}, {2.0 / 3.0}, {3.0 / 4.0}, {4.0 / 5.0}, {5.0 / 6.0}};   double[] x = {39.0 / 400.0, 11.0 / 100.0, 31.0 / 240.0, 37.0 / 300.0, 71.0 / 400.0};   System.out.println("det: " + solve(a, b));     for (int i = 0; i < 5; i++) { System.out.printf(Locale.US, "%12.8f %12.4e\n", b[i][0], b[i][0] - x[i]); } } }
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Perl
Perl
sub rref { our @m; local *m = shift; @m or return; my ($lead, $rows, $cols) = (0, scalar(@m), scalar(@{$m[0]}));   foreach my $r (0 .. $rows - 1) { $lead < $cols or return; my $i = $r;   until ($m[$i][$lead]) {++$i == $rows or next; $i = $r; ++$lead == $cols and return;}   @m[$i, $r] = @m[$r, $i]; my $lv = $m[$r][$lead]; $_ /= $lv foreach @{ $m[$r] };   my @mr = @{ $m[$r] }; foreach my $i (0 .. $rows - 1) {$i == $r and next; ($lv, my $n) = ($m[$i][$lead], -1); $_ -= $lv * $mr[++$n] foreach @{ $m[$i] };}   ++$lead;} }   sub display { join("\n" => map join(" " => map(sprintf("%6.2f", $_), @$_)), @{+shift})."\n" }   sub gauss_jordan_invert { my(@m) = @_; my $rows = @m; my @i = identity(scalar @m); push @{$m[$_]}, @{$i[$_]} for 0..$rows-1; rref(\@m); map { splice @$_, 0, $rows } @m; @m; }   sub identity { my($n) = @_; map { [ (0) x $_, 1, (0) x ($n-1 - $_) ] } 0..$n-1 }   my @tests = ( [ [ 2, -1, 0 ], [-1, 2, -1 ], [ 0, -1, 2 ] ], [ [ -1, -2, 3, 2 ], [ -4, -1, 6, 2 ], [ 7, -8, 9, 1 ], [ 1, -2, 1, 3 ] ], );   for my $matrix (@tests) { print "Original Matrix:\n" . display(\@$matrix) . "\n"; my @gj = gauss_jordan_invert( @$matrix ); print "Gauss-Jordan Inverted Matrix:\n" . display(\@gj) . "\n"; my @rt = gauss_jordan_invert( @gj ); print "After round-trip:\n" . display(\@rt) . "\n";} . "\n" }
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#MiniScript
MiniScript
factorWords = {}   maxNr = val(input("Max number? "))   while true factorInput = input("Factor? ") if factorInput == "" then break // Split input parts = factorInput.split(" ") factor = val(parts[0]) word = parts[1] // Assign factor/word factorWords[factor] = word end while   for nr in range(1,maxNr) matchingWords = "" for factor in factorWords.indexes if nr % factor == 0 then matchingWords = matchingWords + factorWords[factor] end if end for if matchingWords then print matchingWords else print nr end for
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Modula-2
Modula-2
MODULE GeneralFizzBuzz; FROM Conversions IMPORT StrToInt; FROM FormatString IMPORT FormatString; FROM Terminal IMPORT Write,WriteString,WriteLn,ReadChar;   TYPE Word = ARRAY[0..63] OF CHAR;   PROCEDURE WriteInt(i : INTEGER); VAR buf : Word; BEGIN FormatString("%i", buf, i); WriteString(buf); END WriteInt;   PROCEDURE ReadInt() : INTEGER; VAR buf : ARRAY[0..9] OF CHAR; c : CHAR; i : INTEGER; BEGIN i := 0; LOOP c := ReadChar(); IF (c=0C) OR (i>9) THEN BREAK ELSIF (c=012C) OR (c=015C) THEN WriteLn; buf[i] := 0C; BREAK ELSIF (c<'0') OR (c>'9') THEN Write(c); buf[i] := 0C; BREAK ELSE Write(c); buf[i] := c; INC(i) END END; StrToInt(buf, i); RETURN i END ReadInt;   PROCEDURE ReadLine() : Word; VAR buf : Word; i : INTEGER; c : CHAR; BEGIN i := 0; WHILE i<HIGH(buf) DO c := ReadChar(); IF (c=0C) OR (c=012C) OR (c=015C) THEN WriteLn; buf[i] := 0C; BREAK ELSE Write(c); buf[i] := c; INC(i) END END; RETURN buf; END ReadLine;   VAR i,max : INTEGER; fa,fb,fc : INTEGER; wa,wb,wc : Word; done : BOOLEAN; BEGIN max := ReadInt();   fa := ReadInt(); wa := ReadLine(); fb := ReadInt(); wb := ReadLine(); fc := ReadInt(); wc := ReadLine();   FOR i:=1 TO max DO done := FALSE; IF i MOD fa = 0 THEN done := TRUE; WriteString(wa); END; IF i MOD fb = 0 THEN done := TRUE; WriteString(wb); END; IF i MOD fc = 0 THEN done := TRUE; WriteString(wc); END; IF NOT done THEN WriteInt(i) END; WriteLn; END;   ReadChar END GeneralFizzBuzz.
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#F.23
F#
let lower = ['a'..'z']   printfn "%A" lower
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Factor
Factor
USING: spelling ; ! ALPHABET   ALPHABET print 0x61 0x7A [a,b] >string print : russian-alphabet-without-io ( -- str ) 0x0430 0x0450 [a,b) >string ; : russian-alphabet ( -- str ) 0x0451 6 russian-alphabet-without-io insert-nth ; russian-alphabet print
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Openscad
Openscad
  echo("Hello world!"); // writes to the console text("Hello world!"); // creates 2D text in the object space linear_extrude(height=10) text("Hello world!"); // creates 3D text in the object space  
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Nim
Nim
type Iterator = iterator(): int   proc `^`*(base: Natural; exp: Natural): int = var (base, exp) = (base, exp) result = 1 while exp != 0: if (exp and 1) != 0: result *= base exp = exp shr 1 base *= base   proc next(s: Iterator): int = for n in s(): return n   proc powers(m: Natural): Iterator = iterator it(): int {.closure.} = for n in 0 ..< int.high: yield n ^ m result = it   iterator filtered(s1, s2: Iterator): int = var v = next(s1) var f = next(s2) while true: if v > f: f = next(s2) continue elif v < f: yield v v = next(s1)   var squares = powers(2) cubes = powers(3) i = 1 for x in filtered(squares, cubes): if i > 20: echo x if i >= 30: break inc i
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Ruby
Ruby
pieces = %i(♔ ♕ ♘ ♘ ♗ ♗ ♖ ♖) regexes = [/♗(..)*♗/, /♖.*♔.*♖/] row = pieces.shuffle.join until regexes.all?{|re| re.match(row)} puts row
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Rust
Rust
use std::collections::BTreeSet;   struct Chess960 ( BTreeSet<String> );   impl Chess960 { fn invoke(&mut self, b: &str, e: &str) { if e.len() <= 1 { let s = b.to_string() + e; if Chess960::is_valid(&s) { self.0.insert(s); } } else { for (i, c) in e.char_indices() { let mut b = b.to_string(); b.push(c); let mut e = e.to_string(); e.remove(i); self.invoke(&b, &e); } } }   fn is_valid(s: &str) -> bool { let k = s.find('K').unwrap(); k > s.find('R').unwrap() && k < s.rfind('R').unwrap() && s.find('B').unwrap() % 2 != s.rfind('B').unwrap() % 2 } }   // Program entry point. fn main() { let mut chess960 = Chess960(BTreeSet::new()); chess960.invoke("", "KQRRNNBB");   for (i, p) in chess960.0.iter().enumerate() { println!("{}: {}", i, p); } }
http://rosettacode.org/wiki/Function_composition
Function composition
Task Create a function, compose,   whose two arguments   f   and   g,   are both functions with one argument. The result of compose is to be a function of one argument, (lets call the argument   x),   which works like applying function   f   to the result of applying function   g   to   x. Example compose(f, g) (x) = f(g(x)) Reference: Function composition Hint: In some languages, implementing compose correctly requires creating a closure.
#AutoHotkey
AutoHotkey
MsgBox % compose("sin","cos",1.5)   compose(f,g,x) { ; function composition Return %f%(%g%(x)) }
http://rosettacode.org/wiki/Function_composition
Function composition
Task Create a function, compose,   whose two arguments   f   and   g,   are both functions with one argument. The result of compose is to be a function of one argument, (lets call the argument   x),   which works like applying function   f   to the result of applying function   g   to   x. Example compose(f, g) (x) = f(g(x)) Reference: Function composition Hint: In some languages, implementing compose correctly requires creating a closure.
#BBC_BASIC
BBC BASIC
REM Create some functions for testing: DEF FNsqr(a) = SQR(a) DEF FNabs(a) = ABS(a)   REM Create the function composition: SqrAbs = FNcompose(FNsqr(), FNabs())   REM Test calling the composition: x = -2 : PRINT ; x, FN(SqrAbs)(x) END   DEF FNcompose(RETURN f%, RETURN g%) LOCAL f$, p% : DIM p% 7 : p%!0 = f% : p%!4 = g% f$ = "(x)=" + CHR$&A4 + "(&" + STR$~p% + ")(" + \ \ CHR$&A4 + "(&" + STR$~(p%+4) + ")(x))" DIM p% LEN(f$) + 4 : $(p%+4) = f$ : !p% = p%+4 = p%
http://rosettacode.org/wiki/Fractal_tree
Fractal tree
Generate and draw a fractal tree. Draw the trunk At the end of the trunk, split by some angle and draw two branches Repeat at the end of each branch until a sufficient level of branching is reached Related tasks Pythagoras Tree
#Action.21
Action!
DEFINE MAXSIZE="12"   INT ARRAY SinTab=[ 0 4 9 13 18 22 27 31 36 40 44 49 53 58 62 66 71 75 79 83 88 92 96 100 104 108 112 116 120 124 128 132 136 139 143 147 150 154 158 161 165 168 171 175 178 181 184 187 190 193 196 199 202 204 207 210 212 215 217 219 222 224 226 228 230 232 234 236 237 239 241 242 243 245 246 247 248 249 250 251 252 253 254 254 255 255 255 256 256 256 256]   INT ARRAY xStack(MAXSIZE),yStack(MAXSIZE),angleStack(MAXSIZE) BYTE ARRAY lenStack(MAXSIZE),dirStack(MAXSIZE) BYTE stacksize=[0]   INT FUNC Sin(INT a) WHILE a<0 DO a==+360 OD WHILE a>360 DO a==-360 OD IF a<=90 THEN RETURN (SinTab(a)) ELSEIF a<=180 THEN RETURN (SinTab(180-a)) ELSEIF a<=270 THEN RETURN (-SinTab(a-180)) ELSE RETURN (-SinTab(360-a)) FI RETURN (0)   INT FUNC Cos(INT a) RETURN (Sin(a-90))   BYTE FUNC IsEmpty() IF stacksize=0 THEN RETURN (1) FI RETURN (0)   BYTE FUNC IsFull() IF stacksize=MAXSIZE THEN RETURN (1) FI RETURN (0)   PROC Push(INT x,y,angle BYTE len,dir) IF IsFull() THEN Break() FI xStack(stacksize)=x yStack(stacksize)=y angleStack(stacksize)=angle lenStack(stacksize)=len dirStack(stacksize)=dir stacksize==+1 RETURN   PROC Pop(INT POINTER x,y,angle BYTE POINTER len,dir) IF IsEmpty() THEN Break() FI stacksize==-1 x^=xStack(stacksize) y^=yStack(stacksize) angle^=angleStack(stacksize) len^=lenStack(stacksize) dir^=dirStack(stacksize) RETURN   PROC DrawTree(INT x,y,len,angle,leftAngle,rightAngle) BYTE depth,dir   Plot(x,y) x==+Cos(angle)*len/256 y==-Sin(angle)*len/256 DrawTo(x,y)   Push(x,y,angle,len,0)   WHILE IsEmpty()=0 DO Pop(@x,@y,@angle,@len,@dir) IF dir<2 THEN Push(x,y,angle,len,dir+1) IF dir=0 THEN angle==-leftAngle ELSE angle==+rightAngle FI   len=13*len/16 Plot(x,y) x==+Cos(angle)*len/256 y==-Sin(angle)*len/256 DrawTo(x,y)   IF IsFull()=0 THEN Push(x,y,angle,len,0) FI FI OD   RETURN   PROC Main() BYTE CH=$02FC,COLOR1=$02C5,COLOR2=$02C6   Graphics(8+16) Color=1 COLOR1=$BA COLOR2=$B2   DrawTree(140,191,40,110,35,15)   DO UNTIL CH#$FF OD CH=$FF RETURN
http://rosettacode.org/wiki/Fractal_tree
Fractal tree
Generate and draw a fractal tree. Draw the trunk At the end of the trunk, split by some angle and draw two branches Repeat at the end of each branch until a sufficient level of branching is reached Related tasks Pythagoras Tree
#Ada
Ada
with Ada.Numerics.Elementary_Functions;   with SDL.Video.Windows.Makers; with SDL.Video.Renderers.Makers; with SDL.Video.Rectangles; with SDL.Events.Events;   procedure Fractal_Tree is   Width  : constant := 600; Height  : constant := 600; Level  : constant := 13; Length  : constant := 130.0; X_Start : constant := 475.0; Y_Start : constant := 580.0; A_Start : constant := -1.54; Angle_1 : constant := 0.10; Angle_2 : constant := 0.35; C_1  : constant := 0.71; C_2  : constant := 0.87;   Window  : SDL.Video.Windows.Window; Renderer : SDL.Video.Renderers.Renderer; Event  : SDL.Events.Events.Events;   procedure Draw_Tree (Level  : in Natural; Length : in Float; Angle  : in Float; X, Y  : in Float) is use SDL; use Ada.Numerics.Elementary_Functions; Pi  : constant  := Ada.Numerics.Pi; X_2  : constant Float := X + Length * Cos (Angle, 2.0 * Pi); Y_2  : constant Float := Y + Length * Sin (Angle, 2.0 * Pi); Line : constant SDL.Video.Rectangles.Line_Segment  := ((C.int (X), C.int (Y)), (C.int (X_2), C.int (Y_2))); begin if Level > 0 then Renderer.Set_Draw_Colour (Colour => (0, 220, 0, 255)); Renderer.Draw (Line => Line);   Draw_Tree (Level - 1, C_1 * Length, Angle + Angle_1, X_2, Y_2); Draw_Tree (Level - 1, C_2 * Length, Angle - Angle_2, X_2, Y_2); end if; end Draw_Tree;   procedure Wait is use type SDL.Events.Event_Types; begin loop while SDL.Events.Events.Poll (Event) loop if Event.Common.Event_Type = SDL.Events.Quit then return; end if; end loop; delay 0.100; end loop; end Wait;   begin if not SDL.Initialise (Flags => SDL.Enable_Screen) then return; end if;   SDL.Video.Windows.Makers.Create (Win => Window, Title => "Fractal tree", Position => SDL.Natural_Coordinates'(X => 10, Y => 10), Size => SDL.Positive_Sizes'(Width, Height), Flags => 0); SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface); Renderer.Set_Draw_Colour ((0, 0, 0, 255)); Renderer.Fill (Rectangle => (0, 0, Width, Height));   Draw_Tree (Level, Length, A_Start, X_Start, Y_Start); Window.Update_Surface;   Wait; Window.Finalize; SDL.Finalise; end Fractal_Tree;
http://rosettacode.org/wiki/Fractran
Fractran
FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Horton Conway. A FRACTRAN program is an ordered list of positive fractions P = ( f 1 , f 2 , … , f m ) {\displaystyle P=(f_{1},f_{2},\ldots ,f_{m})} , together with an initial positive integer input n {\displaystyle n} . The program is run by updating the integer n {\displaystyle n} as follows: for the first fraction, f i {\displaystyle f_{i}} , in the list for which n f i {\displaystyle nf_{i}} is an integer, replace n {\displaystyle n} with n f i {\displaystyle nf_{i}}  ; repeat this rule until no fraction in the list produces an integer when multiplied by n {\displaystyle n} , then halt. Conway gave a program for primes in FRACTRAN: 17 / 91 {\displaystyle 17/91} , 78 / 85 {\displaystyle 78/85} , 19 / 51 {\displaystyle 19/51} , 23 / 38 {\displaystyle 23/38} , 29 / 33 {\displaystyle 29/33} , 77 / 29 {\displaystyle 77/29} , 95 / 23 {\displaystyle 95/23} , 77 / 19 {\displaystyle 77/19} , 1 / 17 {\displaystyle 1/17} , 11 / 13 {\displaystyle 11/13} , 13 / 11 {\displaystyle 13/11} , 15 / 14 {\displaystyle 15/14} , 15 / 2 {\displaystyle 15/2} , 55 / 1 {\displaystyle 55/1} Starting with n = 2 {\displaystyle n=2} , this FRACTRAN program will change n {\displaystyle n} to 15 = 2 × ( 15 / 2 ) {\displaystyle 15=2\times (15/2)} , then 825 = 15 × ( 55 / 1 ) {\displaystyle 825=15\times (55/1)} , generating the following sequence of integers: 2 {\displaystyle 2} , 15 {\displaystyle 15} , 825 {\displaystyle 825} , 725 {\displaystyle 725} , 1925 {\displaystyle 1925} , 2275 {\displaystyle 2275} , 425 {\displaystyle 425} , 390 {\displaystyle 390} , 330 {\displaystyle 330} , 290 {\displaystyle 290} , 770 {\displaystyle 770} , … {\displaystyle \ldots } After 2, this sequence contains the following powers of 2: 2 2 = 4 {\displaystyle 2^{2}=4} , 2 3 = 8 {\displaystyle 2^{3}=8} , 2 5 = 32 {\displaystyle 2^{5}=32} , 2 7 = 128 {\displaystyle 2^{7}=128} , 2 11 = 2048 {\displaystyle 2^{11}=2048} , 2 13 = 8192 {\displaystyle 2^{13}=8192} , 2 17 = 131072 {\displaystyle 2^{17}=131072} , 2 19 = 524288 {\displaystyle 2^{19}=524288} , … {\displaystyle \ldots } which are the prime powers of 2. Task Write a program that reads a list of fractions in a natural format from the keyboard or from a string, to parse it into a sequence of fractions (i.e. two integers), and runs the FRACTRAN starting from a provided integer, writing the result at each step. It is also required that the number of steps is limited (by a parameter easy to find). Extra credit Use this program to derive the first 20 or so prime numbers. See also For more on how to program FRACTRAN as a universal programming language, see: J. H. Conway (1987). Fractran: A Simple Universal Programming Language for Arithmetic. In: Open Problems in Communication and Computation, pages 4–26. Springer. J. H. Conway (2010). "FRACTRAN: A simple universal programming language for arithmetic". In Jeffrey C. Lagarias. The Ultimate Challenge: the 3x+1 problem. American Mathematical Society. pp. 249–264. ISBN 978-0-8218-4940-8. Zbl 1216.68068. Number Pathology: Fractran by Mark C. Chu-Carroll; October 27, 2006.
#ALGOL_68
ALGOL 68
# as the numbers required for finding the first 20 primes are quite large, # # we use Algol 68G's LONG LONG INT with a precision of 100 digits # PR precision 100 PR   # mode to hold fractions # MODE FRACTION = STRUCT( INT numerator, INT denominator );   # define / between two INTs to yield a FRACTION # OP / = ( INT a, b )FRACTION: ( a, b );   # mode to define a FRACTRAN progam # MODE FRACTRAN = STRUCT( FLEX[0]FRACTION data , LONG LONG INT n , BOOL halted ); # prepares a FRACTRAN program for use - sets the initial value of n and halted to FALSE # PRIO STARTAT = 1; OP STARTAT = ( REF FRACTRAN f, INT start )REF FRACTRAN: BEGIN halted OF f := FALSE; n OF f := start; f END;   # sets n OF f to the next number in the sequence or sets halted OF f to TRUE if the sequence has ended # OP NEXT = ( REF FRACTRAN f )LONG LONG INT: IF halted OF f THEN n OF f := 0 ELSE BOOL found := FALSE; LONG LONG INT result := 0; FOR pos FROM LWB data OF f TO UPB data OF f WHILE NOT found DO LONG LONG INT value = n OF f * numerator OF ( ( data OF f )[ pos ] ); INT denominator = denominator OF ( ( data OF f )[ pos ] ); IF found := ( value MOD denominator = 0 ) THEN result := value OVER denominator FI OD; IF NOT found THEN halted OF f := TRUE FI; n OF f := result FI ;   # generate and print the sequence of numbers from a FRACTRAN pogram # PROC print fractran sequence = ( REF FRACTRAN f, INT start, INT limit )VOID: BEGIN VOID( f STARTAT start ); print( ( "0: ", whole( start, 0 ) ) ); FOR i TO limit WHILE VOID( NEXT f ); NOT halted OF f DO print( ( " " + whole( i, 0 ) + ": " + whole( n OF f, 0 ) ) ) OD; print( ( newline ) ) END ;   # print the first 16 elements from the primes FRACTRAN program # FRACTRAN pf := ( ( 17/91, 78/85, 19/51, 23/38, 29/33, 77/29, 95/23, 77/19, 1/17, 11/13, 13/11, 15/14, 15/2, 55/1 ), 0, FALSE ); print fractran sequence( pf, 2, 15 );   # find some primes using the pf FRACTRAN progam - n is prime for the members in the sequence that are 2^n # INT primes found := 0; VOID( pf STARTAT 2 ); INT pos := 0; print( ( "seq position prime sequence value", newline ) ); WHILE primes found < 20 AND NOT halted OF pf DO LONG LONG INT value := NEXT pf; INT power of 2 := 0; pos +:= 1; WHILE value MOD 2 = 0 AND value > 0 DO power of 2 PLUSAB 1; value OVERAB 2 OD; IF value = 1 THEN # found a prime # primes found +:= 1; print( ( whole( pos, -12 ) + " " + whole( power of 2, -6 ) + " (" + whole( n OF pf, 0 ) + ")", newline ) ) FI OD
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Julia
Julia
using FTPClient   ftp = FTP(hostname = "ftp.ed.ac.uk", username = "anonymous") cd(ftp, "pub/courses") println(readdir(ftp)) bytes = read(download(ftp, "make.notes.tar"))   close(ftp)
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Kotlin
Kotlin
headers = /usr/include/ftplib.h linkerOpts.linux = -L/usr/lib -lftp --- #include <sys/time.h> struct NetBuf { char *cput,*cget; int handle; int cavail,cleft; char *buf; int dir; netbuf *ctrl; netbuf *data; int cmode; struct timeval idletime; FtpCallback idlecb; void *idlearg; int xfered; int cbbytes; int xfered1; char response[256]; };
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Lingo
Lingo
CURLOPT_URL = 10002 ch = xtra("Curl").new() url = "ftp://domain.com"   -- change to remote dir "/foo/bar/" put "/foo/bar/" after url   ch.setOption(CURLOPT_URL, url) res = ch.exec(1)   -- print raw FTP listing as string put res.readRawString(res.length)   -- download file "download.mp3" (passive mode is the internal default behavior) filename = "download.mp3" ch.setOption(CURLOPT_URL, url & filename) ch.setDestinationFile(_movie.path & filename) res = ch.exec()
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#LiveCode
LiveCode
libURLSetFTPMode "passive" --default is passive anyway put url "ftp://ftp.hq.nasa.gov/" into listing repeat for each line ftpln in listing set itemdel to space if the first char of (the first item of ftpln) is "d" then -- is a directory put the last item of ftpln after dirlist else put the last item of ftpln after filelist end if end repeat   put listing //(subset) // -rw-r--r-- 1 ftpadmin ftp-adm 3997 May 26 1998 README // drwxrwsr-x 17 ftpadmin ftp-adm 4096 Sep 10 16:08 pub   put dirlist // armd // chmgt // incoming // lost+found // office // pub   put filelist // README // ftp-exec // index.html // robots.txt   -- downloading a file (upload is same, but use put) -- you don't have to cd manually -- file up/down transfer is binary in livecode (always enforced by livecode) put URL "ftp://ftp.hq.nasa.gov/pub/robots.txt" into URL "file:myFile.txt"   You can execute any ftp command using the libURLftpCommand command e.g. to know the working directory, issue "pwd", we could issue "list" for above too, but using an url with slash on the end with the ftp protocol causes a dir listing by default. put libURLftpCommand("PWD",ftp.example.org)
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#PARI.2FGP
PARI/GP
long foo(GEN a, GEN b)
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Perl
Perl
sub noargs(); # Declare a function with no arguments sub twoargs($$); # Declare a function with two scalar arguments. The two sigils act as argument type placeholders sub noargs :prototype(); # Using the :attribute syntax instead sub twoargs :prototype($$);
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#Phix
Phix
forward function noargs() -- Declare a function with no arguments forward procedure twoargs(integer a, integer b) -- Declare a procedure with two arguments forward procedure twoargs(integer, integer /*b*/) -- Parameter names are optional in forward (and actual) definitions forward function anyargs(sequence s) -- varargs are [best/often] handled as a (single) sequence in Phix forward function atleastonearg(integer a, integer b=1, ...); -- Default makes args optional (== actual defn)
http://rosettacode.org/wiki/Function_definition
Function definition
A function is a body of code that returns a value. The value returned may depend on arguments provided to the function. Task Write a definition of a function called "multiply" that takes two arguments and returns their product. (Argument types should be chosen so as not to distract from showing how functions are created and values returned). Related task   Function prototype
#AArch64_Assembly
AArch64 Assembly
  /* ARM assembly AARCH64 Raspberry PI 3B */ /* program functMul64.s */   /*******************************************/ /* Constantes file */ /*******************************************/ /* for this file see task include a file in language AArch64 assembly*/ .include "../includeConstantesARM64.inc"   /***********************/ /* Initialized data */ /***********************/ .data szRetourLigne: .asciz "\n" szMessResult: .asciz "Resultat : @ \n" // message result /*********************** /* No Initialized data */ /***********************/ .bss sZoneConv: .skip 24 .text .global main main: // function multiply mov x0,8 mov x1,50 bl multiply // call function ldr x1,qAdrsZoneConv bl conversion10S // call function with 2 parameter (x0,x1) ldr x0,qAdrszMessResult ldr x1,qAdrsZoneConv bl strInsertAtCharInc // insert result at @ character bl affichageMess // display message   mov x0,0 // return code   100: // end of program mov x8,EXIT // request to exit program svc 0 // perform the system call qAdrsZoneConv: .quad sZoneConv qAdrszMessResult: .quad szMessResult /******************************************************************/ /* Function multiply */ /******************************************************************/ /* x0 contains value 1 */ /* x1 contains value 2 */ /* x0 return résult */ multiply: mul x0,x1,x0 ret // return function /********************************************************/ /* File Include fonctions */ /********************************************************/ /* for this file see task include a file in language AArch64 assembly */ .include "../includeARM64.inc"  
http://rosettacode.org/wiki/French_Republican_calendar
French Republican calendar
Write a program to convert dates between the Gregorian calendar and the French Republican calendar. The year 1 of the Republican calendar began on 22 September 1792. There were twelve months (Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor) of 30 days each, followed by five intercalary days or Sansculottides (Fête de la vertu / Virtue Day, Fête du génie / Talent Day, Fête du travail / Labour Day, Fête de l'opinion / Opinion Day, and Fête des récompenses / Honours Day). In leap years (the years 3, 7, and 11) a sixth Sansculottide was added: Fête de la Révolution / Revolution Day. As a minimum, your program should give correct results for dates in the range from 1 Vendémiaire 1 = 22 September 1792 to 10 Nivôse 14 = 31 December 1805 (the last day when the Republican calendar was officially in use). If you choose to accept later dates, be aware that there are several different methods (described on the Wikipedia page) about how to determine leap years after the year 14. You should indicate which method you are using. (Because of these different methods, correct programs may sometimes give different results for dates after 1805.) Test your program by converting the following dates both from Gregorian to Republican and from Republican to Gregorian: • 1 Vendémiaire 1 = 22 September 1792 • 1 Prairial 3 = 20 May 1795 • 27 Messidor 7 = 15 July 1799 (Rosetta Stone discovered) • Fête de la Révolution 11 = 23 September 1803 • 10 Nivôse 14 = 31 December 1805
#Phix
Phix
with javascript_semantics constant gregorians = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"}, gregorian = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}, republicans = {"Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse", "Ventôse", "Germinal", "Floréal", "Prairial", "Messidor", "Thermidor", "Fructidor"}, sansculottides = {"Fête de la vertu", "Fête du génie", "Fête du travail", "Fête de l'opinion", "Fête des récompenses", "Fête de la Révolution"} function rep_leap(integer year) return mod(year+1,4)==0 and (mod(year+1,100)!=0 or mod(year+1,400)==0) end function function rep_to_day(sequence dmy) integer {d, m, y} = dmy if m == 13 then m -= 1 d += 30 end if if rep_leap(y) then d -= 1 end if integer res = 365*(y-1) + floor((y+1)/4) - floor((y+1)/100) + floor((y+1)/400) + 30*(m-1) + d return res end function function gre_leap(integer year) return mod(year,4)==0 and (mod(year,100)!=0 or mod(year,400)==0) end function function gre_to_day(sequence dmy) integer {d, m, y} = dmy if m < 3 then y -= 1 m += 12 end if integer res = floor(y*365.25) - floor(y/100) + floor(y/400) + floor(30.6*(m+1)) + d - 654842 return res end function function day_to_rep(integer day) integer y = floor((day-1)/365.25) if not rep_leap(y) then y += 1 end if integer d = day - floor(y*365.25) + 365 + floor(y/100) - floor(y/400), m = 1, sansculottide = 5+rep_leap(y) while d>30 do d -= 30 m += 1 if m == 13 then if d > sansculottide then d -= sansculottide m = 1 y += 1 sansculottide = 5 + rep_leap(y) end if end if end while return {d,m,y} end function function day_to_gre(integer day) integer y = floor(day/365.25), d = day - floor(y*365.25) + 21, m = 9 y += 1792 d += floor(y/100) - floor(y/400) - 13 sequence gregoriam = deep_copy(gregorian) -- (modifiable copy) while d>gregoriam[m] do d -= gregoriam[m] m += 1 if m == 13 then m = 1 y += 1 gregoriam[2] = 28 + gre_leap(y) end if end while return {d,m,y} end function function greg_to_frep(string greg) {integer day, string months, integer year} = scanf(greg,"%d %s %d")[1] integer month = find(months,gregorians) {day,month,year} = day_to_rep(gre_to_day({day,month,year})) string frep = iff(month=13?sprintf("%s %d",{sansculottides[day], year}) :sprintf("%d %s %d",{day, republicans[month], year})) return frep end function function frep_to_greg(string frep) integer day, month, year string months, days if frep[1]<='9' then {day, months, year} = scanf(frep,"%d %s %d")[1] month = find(months,republicans) else {days, year} = scanf(frep,"%s %d")[1] day = find(days,sansculottides) month = 13 end if {day,month,year} = day_to_gre(rep_to_day({day, month, year})) string greg = sprintf("%02d %s %d",{day, gregorians[month], year}) return greg end function constant test_data = { { "22 September 1792", "1 Vendémiaire 1" }, { "20 May 1795", "1 Prairial 3" }, { "15 July 1799", "27 Messidor 7" }, { "23 September 1803", "Fête de la Révolution 11" }, { "31 December 1805", "10 Nivôse 14" }, { "18 March 1871", "27 Ventôse 79" }, { "25 August 1944", "7 Fructidor 152" }, { "19 September 2016", "Fête du travail 224" }, { "06 May 1871", "16 Floréal 79" }, -- Paris Commune begins { "23 May 1871", "3 Prairial 79" }, -- Paris Commune ends { "09 November 1799", "18 Brumaire 8" }, -- Revolution ends by Napoléon coup { "02 December 1804", "11 Frimaire 13" }, -- Republic ends by Napoléon coronation { "30 October 1794", "9 Brumaire 3" }, -- École Normale Supérieure established { "27 July 1794", "9 Thermidor 2" }, -- Robespierre falls { "27 May 1799", "8 Prairial 7" }, -- Fromental Halévy born { "22 September 1792", "1 Vendémiaire 1" }, { "22 September 1793", "1 Vendémiaire 2" }, { "22 September 1794", "1 Vendémiaire 3" }, { "23 September 1795", "1 Vendémiaire 4" }, { "22 September 1796", "1 Vendémiaire 5" }, { "22 September 1797", "1 Vendémiaire 6" }, { "22 September 1798", "1 Vendémiaire 7" }, { "23 September 1799", "1 Vendémiaire 8" }, { "23 September 1800", "1 Vendémiaire 9" }, { "23 September 1801", "1 Vendémiaire 10" }, { "23 September 1802", "1 Vendémiaire 11" }, { "24 September 1803", "1 Vendémiaire 12" }, { "23 September 1804", "1 Vendémiaire 13" }, { "23 September 1805", "1 Vendémiaire 14" }, { "23 September 1806", "1 Vendémiaire 15" }, { "24 September 1807", "1 Vendémiaire 16" }, { "23 September 1808", "1 Vendémiaire 17" }, { "23 September 1809", "1 Vendémiaire 18" }, { "23 September 1810", "1 Vendémiaire 19" }, { "24 September 1811", "1 Vendémiaire 20" }, { "23 September 2015", "1 Vendémiaire 224" }, { "21 September 2016", "Fête des récompenses 224" }, { "22 September 2016", "1 Vendémiaire 225" }, { "23 September 2016", "2 Vendémiaire 225" }, { "22 September 2017", "1 Vendémiaire 226" }, { "28 September 2017", "7 Vendémiaire 226" } } for i=1 to length(test_data) do string {greg, frep} = test_data[i], frep2 = greg_to_frep(greg), greg2 = frep_to_greg(frep), ok = iff(frep=frep2 and greg=greg2?"ok":"**** ERROR ****") if platform()=WINDOWS then -- the windows console does not handle -- non-basic-latin-ascii characters well... frep = substitute_all(frep,"éêéô","eeeo") end if printf(1,"%18s <==> %-25s %s\n",{greg,frep,ok}) end for --sanity test: for i=1 to 150000 do -- (years 1792..~2203) if rep_to_day(day_to_rep(i))!=i then ?9/0 end if if gre_to_day(day_to_gre(i))!=i then ?9/0 end if end for
http://rosettacode.org/wiki/Fusc_sequence
Fusc sequence
Definitions The   fusc   integer sequence is defined as:   fusc(0) = 0   fusc(1) = 1   for n>1,   the   nth   term is defined as:   if   n   is even;     fusc(n) = fusc(n/2)   if   n   is   odd;     fusc(n) = fusc((n-1)/2)   +   fusc((n+1)/2) Note that MathWorld's definition starts with unity, not zero.   This task will be using the OEIS' version   (above). An observation   fusc(A) = fusc(B) where   A   is some non-negative integer expressed in binary,   and where   B   is the binary value of   A   reversed. Fusc numbers are also known as:   fusc function   (named by Dijkstra, 1982)   Stern's Diatomic series   (although it starts with unity, not zero)   Stern-Brocot sequence   (although it starts with unity, not zero) Task   show the first   61   fusc numbers (starting at zero) in a horizontal format.   show the fusc number (and its index) whose length is greater than any previous fusc number length.   (the length is the number of decimal digits when the fusc number is expressed in base ten.)   show all numbers with commas   (if appropriate).   show all output here. Related task   RosettaCode Stern-Brocot sequence Also see   the MathWorld entry:   Stern's Diatomic Series.   the OEIS entry:   A2487.
#C.2B.2B
C++
#include <iomanip> #include <iostream> #include <limits> #include <sstream> #include <vector>   const int n = 61; std::vector<int> l{ 0, 1 };   int fusc(int n) { if (n < l.size()) return l[n]; int f = (n & 1) == 0 ? l[n >> 1] : l[(n - 1) >> 1] + l[(n + 1) >> 1]; l.push_back(f); return f; }   int main() { bool lst = true; int w = -1; int c = 0; int t; std::string res; std::cout << "First " << n << " numbers in the fusc sequence:\n"; for (int i = 0; i < INT32_MAX; i++) { int f = fusc(i); if (lst) { if (i < 61) { std::cout << f << ' '; } else { lst = false; std::cout << "\nPoints in the sequence where an item has more digits than any previous items:\n"; std::cout << std::setw(11) << "Index\\" << " " << std::left << std::setw(9) << "/Value\n"; std::cout << res << '\n'; res = ""; } } std::stringstream ss; ss << f; t = ss.str().length(); ss.str(""); ss.clear(); if (t > w) { w = t; res += (res == "" ? "" : "\n"); ss << std::setw(11) << i << " " << std::left << std::setw(9) << f; res += ss.str(); if (!lst) { std::cout << res << '\n'; res = ""; } if (++c > 5) { break; } } } return 0; }
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Phix
Phix
else -- rType=FUNC|TYPE log_function_call(rtnNo)
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#PicoLisp
PicoLisp
(let Freq NIL (for "L" (filter pair (extract getd (all))) (for "F" (filter atom (fish '((X) (or (circ? X) (getd X))) "L" ) ) (accu 'Freq "F" 1) ) ) (for X (head 10 (flip (by cdr sort Freq))) (tab (-7 4) (car X) (cdr X)) ) )
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Python
Python
import ast   class CallCountingVisitor(ast.NodeVisitor):   def __init__(self): self.calls = {}   def visit_Call(self, node): if isinstance(node.func, ast.Name): fun_name = node.func.id call_count = self.calls.get(fun_name, 0) self.calls[fun_name] = call_count + 1 self.generic_visit(node)   filename = input('Enter a filename to parse: ') with open(filename, encoding='utf-8') as f: contents = f.read() root = ast.parse(contents, filename=filename) #NOTE: this will throw a SyntaxError if the file isn't valid Python code visitor = CallCountingVisitor() visitor.visit(root) top10 = sorted(visitor.calls.items(), key=lambda x: x[1], reverse=True)[:10] for name, count in top10: print(name,'called',count,'times')  
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#Clojure
Clojure
(defn gamma "Returns Gamma(z + 1 = number) using Lanczos approximation." [number] (if (< number 0.5) (/ Math/PI (* (Math/sin (* Math/PI number)) (gamma (- 1 number)))) (let [n (dec number) c [0.99999999999980993 676.5203681218851 -1259.1392167224028 771.32342877765313 -176.61502916214059 12.507343278686905 -0.13857109526572012 9.9843695780195716e-6 1.5056327351493116e-7]] (* (Math/sqrt (* 2 Math/PI)) (Math/pow (+ n 7 0.5) (+ n 0.5)) (Math/exp (- (+ n 7 0.5))) (+ (first c) (apply + (map-indexed #(/ %2 (+ n %1 1)) (next c))))))))
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#JavaScript
JavaScript
const readline = require('readline');   /** * Galton Box animation * @param {number} layers The number of layers in the board * @param {number} balls The number of balls to pass through */ const galtonBox = (layers, balls) => { const speed = 100; const ball = 'o'; const peg = '.'; const result = [];   const sleep = ms => new Promise(resolve => { setTimeout(resolve,ms) });   /** * The board is represented as a 2D array. * @type {Array<Array<string>>} */ const board = [...Array(layers)] .map((e, i) => { const sides = Array(layers - i).fill(' '); const a = Array(i + 1).fill(peg).join(' ').split(''); return [...sides, ...a, ...sides]; });   /** * @return {Array<string>} */ const emptyRow = () => Array(board[0].length).fill(' ');   /** * @param {number} i * @returns {number} */ const bounce = i => Math.round(Math.random()) ? i - 1 : i + 1;   /** * Prints the current state of the board and the collector */ const show = () => { readline.cursorTo(process.stdout, 0, 0); readline.clearScreenDown(process.stdout); board.forEach(e => console.log(e.join(''))); result.reverse(); result.forEach(e => console.log(e.join(''))); result.reverse(); };     /** * Collect the result. * @param {number} idx */ const appendToResult = idx => { const row = result.find(e => e[idx] === ' '); if (row) { row[idx] = ball; } else { const newRow = emptyRow(); newRow[idx] = ball; result.push(newRow); } };   /** * Move the balls through the board * @returns {boolean} True if the there are balls in the board. */ const iter = () => { let hasNext = false; [...Array(bordSize)].forEach((e, i) => { const rowIdx = (bordSize - 1) - i; const idx = board[rowIdx].indexOf(ball); if (idx > -1) { board[rowIdx][idx] = ' '; const nextRowIdx = rowIdx + 1; if (nextRowIdx < bordSize) { hasNext = true; const nextRow = board[nextRowIdx]; nextRow[bounce(idx)] = ball; } else { appendToResult(idx); } } }); return hasNext; };   /** * Add a ball to the board. * @returns {number} The number of balls left to add. */ const addBall = () => { board[0][apex] = ball; balls = balls - 1; return balls; };   board.unshift(emptyRow()); result.unshift(emptyRow());   const bordSize = board.length; const apex = board[1].indexOf(peg);   /** * Run the animation */ (async () => { while (addBall()) { await sleep(speed).then(show); iter(); } await sleep(speed).then(show); while (iter()) { await sleep(speed).then(show); } await sleep(speed).then(show); })();     };   galtonBox(12, 50);
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#J
J
  gapful =: 0 = (|~ ({.,{:)&.(10&#.inv))   task =: 100&$: :(dyad define) NB. MINIMUM task TALLY gn =. y {. (#~ gapful&>) x + i. y * 25 assert 0 ~: {: gn 'The first ' , (": y) , ' gapful numbers exceeding ' , (":<:x) , ' are ' , (":gn) )  
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Java
Java
import java.util.List;   public class GapfulNumbers { private static String commatize(long n) { StringBuilder sb = new StringBuilder(Long.toString(n)); int le = sb.length(); for (int i = le - 3; i >= 1; i -= 3) { sb.insert(i, ','); } return sb.toString(); }   public static void main(String[] args) { List<Long> starts = List.of((long) 1e2, (long) 1e6, (long) 1e7, (long) 1e9, (long) 7123); List<Integer> counts = List.of(30, 15, 15, 10, 25); for (int i = 0; i < starts.size(); ++i) { int count = 0; Long j = starts.get(i); long pow = 100; while (j >= pow * 10) { pow *= 10; } System.out.printf("First %d gapful numbers starting at %s:\n", counts.get(i), commatize(starts.get(i))); while (count < counts.get(i)) { long fl = (j / pow) * 10 + (j % 10); if (j % fl == 0) { System.out.printf("%d ", j); count++; } j++; if (j >= 10 * pow) { pow *= 10; } } System.out.println('\n'); } } }
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#JavaScript
JavaScript
// Lower Upper Solver function lusolve(A, b, update) { var lu = ludcmp(A, update) if (lu === undefined) return // Singular Matrix! return lubksb(lu, b, update) }   // Lower Upper Decomposition function ludcmp(A, update) { // A is a matrix that we want to decompose into Lower and Upper matrices. var d = true var n = A.length var idx = new Array(n) // Output vector with row permutations from partial pivoting var vv = new Array(n) // Scaling information   for (var i=0; i<n; i++) { var max = 0 for (var j=0; j<n; j++) { var temp = Math.abs(A[i][j]) if (temp > max) max = temp } if (max == 0) return // Singular Matrix! vv[i] = 1 / max // Scaling }   if (!update) { // make a copy of A var Acpy = new Array(n) for (var i=0; i<n; i++) { var Ai = A[i] Acpyi = new Array(Ai.length) for (j=0; j<Ai.length; j+=1) Acpyi[j] = Ai[j] Acpy[i] = Acpyi } A = Acpy }   var tiny = 1e-20 // in case pivot element is zero for (var i=0; ; i++) { for (var j=0; j<i; j++) { var sum = A[j][i] for (var k=0; k<j; k++) sum -= A[j][k] * A[k][i]; A[j][i] = sum } var jmax = 0 var max = 0; for (var j=i; j<n; j++) { var sum = A[j][i] for (var k=0; k<i; k++) sum -= A[j][k] * A[k][i]; A[j][i] = sum var temp = vv[j] * Math.abs(sum) if (temp >= max) { max = temp jmax = j } } if (i <= jmax) { for (var j=0; j<n; j++) { var temp = A[jmax][j] A[jmax][j] = A[i][j] A[i][j] = temp } d = !d; vv[jmax] = vv[i] } idx[i] = jmax; if (i == n-1) break; var temp = A[i][i] if (temp == 0) A[i][i] = temp = tiny temp = 1 / temp for (var j=i+1; j<n; j++) A[j][i] *= temp } return {A:A, idx:idx, d:d} }   // Lower Upper Back Substitution function lubksb(lu, b, update) { // solves the set of n linear equations A*x = b. // lu is the object containing A, idx and d as determined by the routine ludcmp. var A = lu.A var idx = lu.idx var n = idx.length   if (!update) { // make a copy of b var bcpy = new Array(n) for (var i=0; i<b.length; i+=1) bcpy[i] = b[i] b = bcpy }   for (var ii=-1, i=0; i<n; i++) { var ix = idx[i] var sum = b[ix] b[ix] = b[i] if (ii > -1) for (var j=ii; j<i; j++) sum -= A[i][j] * b[j] else if (sum) ii = i b[i] = sum } for (var i=n-1; i>=0; i--) { var sum = b[i] for (var j=i+1; j<n; j++) sum -= A[i][j] * b[j] b[i] = sum / A[i][i] } return b // solution vector x }   document.write( lusolve( [ [1.00, 0.00, 0.00, 0.00, 0.00, 0.00], [1.00, 0.63, 0.39, 0.25, 0.16, 0.10], [1.00, 1.26, 1.58, 1.98, 2.49, 3.13], [1.00, 1.88, 3.55, 6.70, 12.62, 23.80], [1.00, 2.51, 6.32, 15.88, 39.90, 100.28], [1.00, 3.14, 9.87, 31.01, 97.41, 306.02] ], [-0.01, 0.61, 0.91, 0.99, 0.60, 0.02] ) )
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#Phix
Phix
with javascript_semantics function ToReducedRowEchelonForm(sequence M) integer lead = 1, rowCount = length(M), columnCount = length(M[1]), i for r=1 to rowCount do if lead>=columnCount then exit end if i = r while M[i][lead]=0 do i += 1 if i=rowCount then i = r lead += 1 if lead=columnCount then exit end if end if end while object mr = sq_div(M[i],M[i][lead]) M[i] = M[r] M[r] = mr for j=1 to rowCount do if j!=r then M[j] = sq_sub(M[j],sq_mul(M[j][lead],M[r])) end if end for lead += 1 end for return M end function --</end of copy> function inverse(sequence mat) integer len = length(mat) sequence aug = repeat(repeat(0,2*len),len) for i=1 to len do if length(mat[i])!=len then ?9/0 end if -- "Not a square matrix" for j=1 to len do aug[i][j] = mat[i][j] end for -- augment by identity matrix to right aug[i][i + len] = 1 end for aug = ToReducedRowEchelonForm(aug) sequence inv = repeat(repeat(0,len),len) -- remove identity matrix to left for i=1 to len do for j=len+1 to 2*len do inv[i][j-len] = aug[i][j] end for end for return inv end function constant test = {{ 2, -1, 0}, {-1, 2, -1}, { 0, -1, 2}} pp(inverse(test),{pp_Nest,1})
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Nanoquery
Nanoquery
factors = {} words = {}   // get the max number print ">" max = int(input())   // get the factors inp = " " while inp != "" print ">" inp = input() if " " in inp factors.append(int(split(inp, " ")[0])) words.append(split(inp, " ")[1]) end end   // output all the numbers for i in range(1, max) foundfactor = false for j in range(0, len(factors) - 1) if (i % factors[j]) = 0 foundfactor = true print words[j] end end j = 0   if !foundfactor print i end println end
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Nim
Nim
  import parseutils, strutils, algorithm   type FactorAndWord = tuple[factor:int, word: string]   var number: int var factorAndWords: array[3, FactorAndWord]   #custom comparison proc for the FactorAndWord type proc customCmp(x,y: FactorAndWord): int = if x.factor < y.factor: -1 elif x.factor > y.factor: 1 else: 0   echo "Enter max number:" var input = readLine(stdin) discard parseInt(input, number)   for i in 0..2:   echo "Enter a number and word separated by space:" var input = readLine(stdin)   var tokens = input.split discard parseInt(tokens[0], factorAndWords[i].factor) factorAndWords[i].word = tokens[1]   #sort factors in ascending order sort(factorAndWords, customCmp)   #implement fiz buz for i in 1..number: var written = false; for item in items(factorAndWords): if i mod item.factor == 0 : write(stdout, item.word) written = true if written : write(stdout, "\n") else : writeLine(stdout, i)      
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#FALSE
FALSE
'a[$'z>~][$,1+]#%
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Fermat
Fermat
Array locase[1,26]; [locase]:=[<i=1,26>'a'+i-1]; !([locase:char);
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Oxygene
Oxygene
  namespace HelloWorld;   interface   type HelloClass = class public class method Main; end;   implementation   class method HelloClass.Main; begin writeLn('Hello world!'); end;   end.  
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#OCaml
OCaml
  (* Task : Generator/Exponential   Version using the Seq module types, but transparently *)   (*** Helper functions ***)   (* Generator type *) type 'a gen = unit -> 'a node and 'a node = Nil | Cons of 'a * 'a gen   (* Power function on integers *) let power (base : int) (exp : int) : int = let rec helper exp acc = if exp = 0 then acc else helper (exp - 1) (base * acc) in helper exp 1   (* Take (at most) n from generator *) let rec take (n : int) (gen : 'a gen) : 'a list = if n = 0 then [] else match gen () with | Nil -> [] | Cons (x, tl) -> x :: take (n - 1) tl   (* Stop existing generator at a given condition *) let rec keep_while (p : 'a -> bool) (gen : 'a gen) : 'a gen = fun () -> match gen () with | Nil -> Nil | Cons (x, tl) -> if p x then Cons (x, keep_while p tl) else Nil   (* Drop the first n elements of a generator *) let rec drop (n : int) (gen : 'a gen) : 'a gen = if n = 0 then gen else match gen () with | Nil -> (fun () -> Nil) | Cons (_, tl) -> drop (n - 1) tl   (* Filter based on predicate, lazily *) let rec filter (p : 'a -> bool) (gen : 'a gen) : 'a gen = fun () -> match gen () with | Nil -> Nil | Cons (x, tl) -> if p x then Cons (x, filter p tl) else filter p tl ()   (* Is this value inside this generator? Does not terminate for infinite streams! *) let rec mem (val_ : 'a) (gen : 'a gen) : bool = match gen () with | Nil -> false | Cons (x, tl) -> if x = val_ then true else mem val_ tl   (*** Task at hand ***)   (* Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). *) let power_gen k : int gen = let rec generator n () = Cons (power n k, generator (n + 1)) in generator 0   (* Use it to create generators of squares and cubes *) let squares = power_gen 2 let cubes = power_gen 3   (* Create a new generator that filters all cubes from the generator of squares. *) let squares_no_cubes = let filter_p square = (* Get all cubes up to square *) let cubes_up_to_n2 = keep_while ((>=) square) cubes in not (mem square cubes_up_to_n2) in filter filter_p squares   (*** Output ***)   (* Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. *) let _ = squares_no_cubes |> drop 20 |> take 10  
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Scala
Scala
import scala.annotation.tailrec   object Chess960 extends App {   private val pieces = List('♖', '♗', '♘', '♕', '♔', '♘', '♗', '♖')   @tailrec private def generateFirstRank(pieces: List[Char]): List[Char] = { def check(rank: String) = rank.matches(".*♖.*♔.*♖.*") && rank.matches(".*♗(..|....|......|)♗.*")   val p = scala.util.Random.shuffle(pieces) if (check(p.toString.replaceAll("[^\\p{Upper}]", ""))) generateFirstRank(pieces) else p }   loop(10)   @tailrec private def loop(n: Int): Unit = { println(generateFirstRank(pieces)) if (n <= 0) () else loop(n - 1) } }
http://rosettacode.org/wiki/Function_composition
Function composition
Task Create a function, compose,   whose two arguments   f   and   g,   are both functions with one argument. The result of compose is to be a function of one argument, (lets call the argument   x),   which works like applying function   f   to the result of applying function   g   to   x. Example compose(f, g) (x) = f(g(x)) Reference: Function composition Hint: In some languages, implementing compose correctly requires creating a closure.
#Bori
Bori
double sin (double v) { return Math.sin(v); } double asin (double v) { return Math.asin(v); } Var compose (Func f, Func g, double d) { return f(g(d)); }   void button1_onClick (Widget widget) { double d = compose(sin, asin, 0.5); label1.setText(d.toString(9)); }
http://rosettacode.org/wiki/Function_composition
Function composition
Task Create a function, compose,   whose two arguments   f   and   g,   are both functions with one argument. The result of compose is to be a function of one argument, (lets call the argument   x),   which works like applying function   f   to the result of applying function   g   to   x. Example compose(f, g) (x) = f(g(x)) Reference: Function composition Hint: In some languages, implementing compose correctly requires creating a closure.
#BQN
BQN
_compose_ ← ∘
http://rosettacode.org/wiki/Fractal_tree
Fractal tree
Generate and draw a fractal tree. Draw the trunk At the end of the trunk, split by some angle and draw two branches Repeat at the end of each branch until a sufficient level of branching is reached Related tasks Pythagoras Tree
#Arturo
Arturo
width: 1000 height: 1000   trunkLength: 400 scaleFactor: 0.6 startingAngle: 1.5 * pi deltaAngle: 0.2 * pi   drawTree: function [out x y len theta][ if len < 1 -> return null   x2: x + len * cos theta y2: y + len * sin theta   'out ++ ~"<line x1='|x|' y1='|y|' x2='|x2|' y2='|y2|' style='stroke: white; stroke-width:1'/>\n"   drawTree out x2 y2 len*scaleFactor theta+deltaAngle drawTree out x2 y2 len*scaleFactor theta-deltaAngle ]   svg: { <?xml version='1.0' encoding='utf-8' standalone='no'?> <!DOCTYPE svg PUBLIC '-//W3C//DTD SVG 1.1//EN' 'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'> <svg width='100%%' height='100%%' version='1.1' xmlns='http://www.w3.org/2000/svg'> <rect width="100%" height="100%" fill="black"/> }   drawTree svg 0.5*width height trunkLength startingAngle 'svg ++ "</svg>"   write "fractal.svg" svg
http://rosettacode.org/wiki/Fractal_tree
Fractal tree
Generate and draw a fractal tree. Draw the trunk At the end of the trunk, split by some angle and draw two branches Repeat at the end of each branch until a sufficient level of branching is reached Related tasks Pythagoras Tree
#AutoHotkey
AutoHotkey
#SingleInstance, Force #NoEnv SetBatchLines, -1   ; Uncomment if Gdip.ahk is not in your standard library ; #Include, Gdip.ahk   FileOut := A_Desktop "\MyNewFile.png" TreeColor := 0xff0066ff ; ARGB TrunkWidth := 10 ; Pixels TrunkLength := 80 ; Pixels Angle := 60 ; Degrees ImageWidth := 670 ; Pixels ImageHeight := 450 ; Pixels Branches := 13 Decrease := 0.81   Angle := (Angle * 0.01745329252) / 2 , Points := {} , Points[1, "Angle"] := 0 , Points[1, "X"] := ImageWidth // 2 , Points[1, "Y"] := ImageHeight - TrunkLength   if (!pToken := Gdip_Startup()) { MsgBox, 48, Gdiplus error!, Gdiplus failed to start. Please ensure you have Gdiplus on your system. ExitApp } OnExit, Exit   pBitmap := Gdip_CreateBitmap(ImageWidth, ImageHeight) , G := Gdip_GraphicsFromImage(pBitmap) , Gdip_SetSmoothingMode(G, 4) , pBrush := Gdip_BrushCreateSolid(0xff000000) , Gdip_FillRectangle(G, pBrush, -5, -5, ImageWidth + 10, ImageHeight + 10) , Gdip_DeleteBrush(pBrush) , pPen := Gdip_CreatePen(TreeColor, TrunkWidth/Decrease) , Gdip_DrawLine(G, pPen, Points.1.X, Points.1.Y, Points.1.X, ImageHeight) , Gdip_DeletePen(pPen)   Loop, % Branches { NewPoints := {} pPen := Gdip_CreatePen(TreeColor, TrunkWidth) for Each, Point in Points { N1 := A_Index * 2 , N2 := (A_Index * 2) + 1 , NewPoints[N1, "X"] := Point.X + (TrunkLength * Sin(NewPoints[N1, "Angle"] := Point.Angle - Angle)) , NewPoints[N1, "Y"] := Point.Y - (TrunkLength * Cos(NewPoints[N1].Angle)) , NewPoints[N2, "X"] := Point.X + (TrunkLength * Sin(NewPoints[N2, "Angle"] := Point.Angle + Angle)) , NewPoints[N2, "Y"] := Point.Y - (TrunkLength * Cos(NewPoints[N2].Angle)) , Gdip_DrawLine(G, pPen, Point.X, Point.Y, NewPoints[N1].X, NewPoints[N1].Y) , Gdip_DrawLine(G, pPen, Point.X, Point.Y, NewPoints[N2].X, NewPoints[N2].Y) } TrunkWidth *= Decrease , TrunkLength *= Decrease , Points := NewPoints , Gdip_DeletePen(pPen) }   Gdip_SaveBitmapToFile(pBitmap, FileOut) , Gdip_DisposeImage(pBitmap) , Gdip_DeleteGraphics(G) Run, % FileOut   Exit: Gdip_Shutdown(pToken) ExitApp
http://rosettacode.org/wiki/Fractran
Fractran
FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Horton Conway. A FRACTRAN program is an ordered list of positive fractions P = ( f 1 , f 2 , … , f m ) {\displaystyle P=(f_{1},f_{2},\ldots ,f_{m})} , together with an initial positive integer input n {\displaystyle n} . The program is run by updating the integer n {\displaystyle n} as follows: for the first fraction, f i {\displaystyle f_{i}} , in the list for which n f i {\displaystyle nf_{i}} is an integer, replace n {\displaystyle n} with n f i {\displaystyle nf_{i}}  ; repeat this rule until no fraction in the list produces an integer when multiplied by n {\displaystyle n} , then halt. Conway gave a program for primes in FRACTRAN: 17 / 91 {\displaystyle 17/91} , 78 / 85 {\displaystyle 78/85} , 19 / 51 {\displaystyle 19/51} , 23 / 38 {\displaystyle 23/38} , 29 / 33 {\displaystyle 29/33} , 77 / 29 {\displaystyle 77/29} , 95 / 23 {\displaystyle 95/23} , 77 / 19 {\displaystyle 77/19} , 1 / 17 {\displaystyle 1/17} , 11 / 13 {\displaystyle 11/13} , 13 / 11 {\displaystyle 13/11} , 15 / 14 {\displaystyle 15/14} , 15 / 2 {\displaystyle 15/2} , 55 / 1 {\displaystyle 55/1} Starting with n = 2 {\displaystyle n=2} , this FRACTRAN program will change n {\displaystyle n} to 15 = 2 × ( 15 / 2 ) {\displaystyle 15=2\times (15/2)} , then 825 = 15 × ( 55 / 1 ) {\displaystyle 825=15\times (55/1)} , generating the following sequence of integers: 2 {\displaystyle 2} , 15 {\displaystyle 15} , 825 {\displaystyle 825} , 725 {\displaystyle 725} , 1925 {\displaystyle 1925} , 2275 {\displaystyle 2275} , 425 {\displaystyle 425} , 390 {\displaystyle 390} , 330 {\displaystyle 330} , 290 {\displaystyle 290} , 770 {\displaystyle 770} , … {\displaystyle \ldots } After 2, this sequence contains the following powers of 2: 2 2 = 4 {\displaystyle 2^{2}=4} , 2 3 = 8 {\displaystyle 2^{3}=8} , 2 5 = 32 {\displaystyle 2^{5}=32} , 2 7 = 128 {\displaystyle 2^{7}=128} , 2 11 = 2048 {\displaystyle 2^{11}=2048} , 2 13 = 8192 {\displaystyle 2^{13}=8192} , 2 17 = 131072 {\displaystyle 2^{17}=131072} , 2 19 = 524288 {\displaystyle 2^{19}=524288} , … {\displaystyle \ldots } which are the prime powers of 2. Task Write a program that reads a list of fractions in a natural format from the keyboard or from a string, to parse it into a sequence of fractions (i.e. two integers), and runs the FRACTRAN starting from a provided integer, writing the result at each step. It is also required that the number of steps is limited (by a parameter easy to find). Extra credit Use this program to derive the first 20 or so prime numbers. See also For more on how to program FRACTRAN as a universal programming language, see: J. H. Conway (1987). Fractran: A Simple Universal Programming Language for Arithmetic. In: Open Problems in Communication and Computation, pages 4–26. Springer. J. H. Conway (2010). "FRACTRAN: A simple universal programming language for arithmetic". In Jeffrey C. Lagarias. The Ultimate Challenge: the 3x+1 problem. American Mathematical Society. pp. 249–264. ISBN 978-0-8218-4940-8. Zbl 1216.68068. Number Pathology: Fractran by Mark C. Chu-Carroll; October 27, 2006.
#AutoHotkey
AutoHotkey
n := 2, steplimit := 15, numerator := [], denominator := [] s := "17/91 78/85 19/51 23/38 29/33 77/29 95/23 77/19 1/17 11/13 13/11 15/14 15/2 55/1"   Loop, Parse, s, % A_Space if (!RegExMatch(A_LoopField, "^(\d+)/(\d+)$", m)) MsgBox, % "Invalid input string (" A_LoopField ")." else numerator[A_Index] := m1, denominator[A_Index] := m2   SetFormat, FloatFast, 0.0 Gui, Add, ListView, R10 W100 -Hdr, | SysGet, VSBW, 2 LV_ModifyCol(1, 95 - VSBW), LV_Add( , 0 ": " n) Gui, Show   Loop, % steplimit { i := A_Index Loop, % numerator.MaxIndex() if (!Mod(nn := n * numerator[A_Index] / denominator[A_Index], 1)) { LV_Modify(LV_Add( , i ": " (n := nn)), "Vis") continue, 2 } break }
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Nim
Nim
import asyncdispatch, asyncftpclient   const Host = "speedtest.tele2.net" Upload = "upload" File = "1KB.zip"   proc main {.async.} =   # Create session and connect. let ftp = newAsyncFtpClient(Host, user = "anonymous", pass = "anything") await ftp.connect() echo "Connected." echo await ftp.send("PASV") # Switch to passive mode.   # Change directory and list its contents. await ftp.cd(Upload) echo "Changed to directory: ", Upload echo "Contents of directory: ", Upload for file in await ftp.listDirs(): echo " ", file   # Download a file. await ftp.cd("/") echo "Returned to root directory." await ftp.retrFile(file = File, dest = File) echo "Downloaded file: ", File echo await ftp.send("QUIT") # Disconnect.   waitFor main()
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Perl
Perl
use Net::FTP;   # set server and credentials my $host = 'speedtest.tele2.net'; my $user = 'anonymous'; my $password = '';   # connect in passive mode my $f = Net::FTP->new($host) or die "Can't open $host\n"; $f->login($user, $password) or die "Can't login as $user\n"; $f->passive();   # change remote directory, list contents $f->cwd('upload'); @files = $f->ls(); printf "Currently %d files in the 'upload' directory.\n", @files;   # download file in binary mode $f->cwd('/'); $f->type('binary'); $local = $f->get('512KB.zip'); print "Your file was stored as $local in the current directory\n";
http://rosettacode.org/wiki/FTP
FTP
Task Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
#Phix
Phix
without js -- libcurl, allocate, file i/o include libcurl.e constant url = "ftp://speedtest.tele2.net/" curl_global_init() atom curl = curl_easy_init(), pErrorBuffer = allocate(CURL_ERROR_SIZE) curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, pErrorBuffer) curl_easy_setopt(curl, CURLOPT_URL, url) object res = curl_easy_perform_ex(curl) if integer(res) then ?{res,peek_string(pErrorBuffer)} else puts(1,res) end if string filename = "1KB.zip" {} = delete_file(filename) res = curl_easy_get_file(url&filename, "", filename) if res=CURLE_OK then printf(1,"successfully downloaded %s (size %s)\n",{filename,get_file_size(filename,true)}) else ?{"error",res} end if
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#PL.2FI
PL/I
  declare s1 entry; declare s2 entry (fixed); declare s3 entry (fixed, float);   declare f1 entry returns (fixed); declare f2 entry (float) returns (float); declare f3 entry (character(*), character(*)) returns (character (20));  
http://rosettacode.org/wiki/Function_prototype
Function prototype
Some languages provide the facility to declare functions and subroutines through the use of function prototyping. Task Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include: An explanation of any placement restrictions for prototype declarations A prototype declaration for a function that does not require arguments A prototype declaration for a function that requires two arguments A prototype declaration for a function that utilizes varargs A prototype declaration for a function that utilizes optional arguments A prototype declaration for a function that utilizes named parameters Example of prototype declarations for subroutines or procedures (if these differ from functions) An explanation and example of any special forms of prototyping not covered by the above Languages that do not provide function prototyping facilities should be omitted from this task.
#PureBasic
PureBasic
;Forward procedure declare defined with no arguments and that returns a string Declare.s booTwo() ;Forward procedure declare defined with two arguments and that returns a float Declare.f moo(x.f, y.f) ;Forward procedure declare with two arguments and an optional argument and that returns a float Declare.f cmoo(x.f, y.f, m.f = 0)   ;*** The following three procedures are defined before their first use. ;Procedure defined with no arguments and that returns a string Procedure.s boo(): ProcedureReturn "boo": EndProcedure ;Procedure defined with two arguments and that returns an float Procedure.f aoo(x.f, y.f): ProcedureReturn x + y: EndProcedure ;Procedure defined with two arguments and an optional argument and that returns a float Procedure.f caoo(x.f, y.f, m.f = 1): ProcedureReturn (x + y) * m: EndProcedure   ;ProtoType defined for any function with no arguments and that returns a string Prototype.s showString() ;Prototype defined for any function with two float arguments and that returns a float Prototype.f doMath(x.f, y.f) ;ProtoType defined for any function with two float arguments and an optional float argument and that returns a float Prototype.f doMathWithOpt(x.f, y.f, m.f = 0)   Define a.f = 12, b.f = 5, c.f = 9 Define proc_1.showString, proc_2.doMath, proc_3.doMathWithOpt ;using defined ProtoTypes If OpenConsole("ProtoTypes and Forward Declarations")   PrintN("Forward Declared procedures:") PrintN(boo()) PrintN(StrF(a, 2) + " * " + StrF(b, 2) + " = " + StrF(moo(a, b), 2)) PrintN(StrF(a, 2) + " * " + StrF(b, 2) + " + " + StrF(c, 2) + " = " + StrF(cmoo(a, b, c), 2)) PrintN(StrF(a, 2) + " * " + StrF(b, 2) + " = " + StrF(cmoo(a, b), 2))   ;set pointers to second set of functions proc_1 = @boo() proc_2 = @aoo() proc_3 = @caoo()   PrintN("ProtoTyped procedures (set 1):") PrintN(proc_1()) PrintN(StrF(a, 2) + " ? " + StrF(b, 2) + " = " + StrF(proc_2(a, b), 2)) PrintN(StrF(a, 2) + " ? " + StrF(b, 2) + " ? " + StrF(c, 2) + " = " + StrF(proc_3(a, b, c), 2)) PrintN(StrF(a, 2) + " ? " + StrF(b, 2) + " = " + StrF(proc_3(a, b), 2))   ;set pointers to second set of functions proc_1 = @booTwo() proc_2 = @moo() proc_3 = @cmoo()   PrintN("ProtoTyped procedures (set 2):") PrintN(proc_1()) PrintN(StrF(a, 2) + " ? " + StrF(b, 2) + " = " + StrF(proc_2(a, b), 2)) PrintN(StrF(a, 2) + " ? " + StrF(b, 2) + " ? " + StrF(c, 2) + " = " + StrF(proc_3(a, b, c), 2)) PrintN(StrF(a, 2) + " ? " + StrF(b, 2) + " = " + StrF(proc_3(a, b), 2))     Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole() EndIf     ;*** If the forward Declaration above are not used then the following Procedure ;definitions each have to be placed before the call to the respective procedure.   ;Procedure defined with no arguments and that returns a string Procedure.s booTwo() ProcedureReturn "booTwo" EndProcedure   ;Procedure defined with two arguments and that returns an float Procedure.f moo(x.f, y.f) ProcedureReturn x * y EndProcedure   ;Procedure defined with two arguments and an optional argument and that returns an float Procedure.f cmoo(x.f, y.f, m.f = 0) ProcedureReturn (x * y) + m EndProcedure  
http://rosettacode.org/wiki/Function_definition
Function definition
A function is a body of code that returns a value. The value returned may depend on arguments provided to the function. Task Write a definition of a function called "multiply" that takes two arguments and returns their product. (Argument types should be chosen so as not to distract from showing how functions are created and values returned). Related task   Function prototype
#ACL2
ACL2
(defun multiply (a b) (* a b))
http://rosettacode.org/wiki/French_Republican_calendar
French Republican calendar
Write a program to convert dates between the Gregorian calendar and the French Republican calendar. The year 1 of the Republican calendar began on 22 September 1792. There were twelve months (Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor) of 30 days each, followed by five intercalary days or Sansculottides (Fête de la vertu / Virtue Day, Fête du génie / Talent Day, Fête du travail / Labour Day, Fête de l'opinion / Opinion Day, and Fête des récompenses / Honours Day). In leap years (the years 3, 7, and 11) a sixth Sansculottide was added: Fête de la Révolution / Revolution Day. As a minimum, your program should give correct results for dates in the range from 1 Vendémiaire 1 = 22 September 1792 to 10 Nivôse 14 = 31 December 1805 (the last day when the Republican calendar was officially in use). If you choose to accept later dates, be aware that there are several different methods (described on the Wikipedia page) about how to determine leap years after the year 14. You should indicate which method you are using. (Because of these different methods, correct programs may sometimes give different results for dates after 1805.) Test your program by converting the following dates both from Gregorian to Republican and from Republican to Gregorian: • 1 Vendémiaire 1 = 22 September 1792 • 1 Prairial 3 = 20 May 1795 • 27 Messidor 7 = 15 July 1799 (Rosetta Stone discovered) • Fête de la Révolution 11 = 23 September 1803 • 10 Nivôse 14 = 31 December 1805
#Raku
Raku
use v6; constant @month_names = < Vendémiaire Brumaire Frimaire Nivôse Pluviôse Ventôse Germinal Floréal Prairial Messidor Thermidor Fructidor >; constant @intercalary = 'Fête de la vertu', 'Fête du génie', 'Fête du travail', "Fête de l'opinion", 'Fête des récompenses', 'Fête de la Révolution', ; constant %month_nums = %( @month_names Z=> 1..12 ); constant %i_cal_nums = %( @intercalary Z=> 1.. 6 ); constant $i_cal_month = 13; constant $epoch = Date.new: '1792-09-22';   sub is_republican_leap_year ( Int:D $year --> Bool ) { my $y := $year + 1; return ?( $y %% 4 and ($y !%% 100 or $y %% 400) ); }   sub Republican_to_Gregorian ( Str:D $rep_date --> Date ) { grammar Republican_date_text { token day { \d+ } token year { \d+ } token ic { @intercalary } token month { @month_names } rule TOP { ^ [ <ic> | <day> <month> ] <year> $ } }   Republican_date_text.parse($rep_date) orelse die "Republican date not recognized: '$rep_date'";   my $day1 := $/<ic> ?? %i_cal_nums{~$/<ic>} !! +$/<day>; my $month1 := $/<month> ?? %month_nums{~$/<month>} !! $i_cal_month;   my @ymd0 := ($/<year>, $month1, $day1) »-» 1; my $days_since_epoch := [+] @ymd0 Z* (365, 30, 1);   my $leap_days := +grep &is_republican_leap_year, 1 ..^ $/<year>; return $epoch + $days_since_epoch + $leap_days; }   sub Gregorian_to_Republican ( Date:D $greg_date --> Str ) { my $days_since_epoch := $greg_date - $epoch; die if $days_since_epoch < 0;   my ( $year, $days ) = 1, $days_since_epoch; loop { my $year_length = 365 + (1 if $year.&is_republican_leap_year); last if $days < $year_length; $days -= $year_length; $year += 1; }   my ( $day0, $month0 ) = $days.polymod( 30 ); my ( $day1, $month1 ) = ($day0, $month0) X+ 1;   return $month1 == $i_cal_month ?? "@intercalary[$day0 ] $year" !! "$day1 @month_names[$month0] $year"; }   my @test_data = ( '1792-09-22', '1 Vendémiaire 1' ), ( '1795-05-20', '1 Prairial 3' ), ( '1799-07-15', '27 Messidor 7' ), ( '1803-09-23', 'Fête de la Révolution 11' ), ( '1805-12-31', '10 Nivôse 14' ),   ( '1871-03-18', '27 Ventôse 79' ), ( '1944-08-25', '7 Fructidor 152' ), ( '2016-09-19', 'Fête du travail 224' ),   ( '1871-05-06', '16 Floréal 79' ), # Paris Commune begins ( '1871-05-23', '3 Prairial 79' ), # Paris Commune ends ( '1799-11-09', '18 Brumaire 8' ), # Revolution ends by Napoléon coup ( '1804-12-02', '11 Frimaire 13' ), # Republic ends by Napoléon coronation ( '1794-10-30', '9 Brumaire 3' ), # École Normale Supérieure established ( '1794-07-27', '9 Thermidor 2' ), # Robespierre falls ( '1799-05-27', '8 Prairial 7' ), # Fromental Halévy born   ( '1792-09-22', '1 Vendémiaire 1' ), ( '1793-09-22', '1 Vendémiaire 2' ), ( '1794-09-22', '1 Vendémiaire 3' ), ( '1795-09-23', '1 Vendémiaire 4' ), ( '1796-09-22', '1 Vendémiaire 5' ), ( '1797-09-22', '1 Vendémiaire 6' ), ( '1798-09-22', '1 Vendémiaire 7' ), ( '1799-09-23', '1 Vendémiaire 8' ), ( '1800-09-23', '1 Vendémiaire 9' ), ( '1801-09-23', '1 Vendémiaire 10' ), ( '1802-09-23', '1 Vendémiaire 11' ), ( '1803-09-24', '1 Vendémiaire 12' ), ( '1804-09-23', '1 Vendémiaire 13' ), ( '1805-09-23', '1 Vendémiaire 14' ), ( '1806-09-23', '1 Vendémiaire 15' ), ( '1807-09-24', '1 Vendémiaire 16' ), ( '1808-09-23', '1 Vendémiaire 17' ), ( '1809-09-23', '1 Vendémiaire 18' ), ( '1810-09-23', '1 Vendémiaire 19' ), ( '1811-09-24', '1 Vendémiaire 20' ), ( '2015-09-23', '1 Vendémiaire 224' ), ( '2016-09-22', '1 Vendémiaire 225' ), ( '2017-09-22', '1 Vendémiaire 226' ), ;   for @test_data -> ( $g_text, $r ) { my $g = Date.new: $g_text;   die if Republican_to_Gregorian($r) != $g or Gregorian_to_Republican($g) ne $r;   die if Gregorian_to_Republican(Republican_to_Gregorian($r)) ne $r or Republican_to_Gregorian(Gregorian_to_Republican($g)) != $g; } say 'All tests successful.';
http://rosettacode.org/wiki/Fusc_sequence
Fusc sequence
Definitions The   fusc   integer sequence is defined as:   fusc(0) = 0   fusc(1) = 1   for n>1,   the   nth   term is defined as:   if   n   is even;     fusc(n) = fusc(n/2)   if   n   is   odd;     fusc(n) = fusc((n-1)/2)   +   fusc((n+1)/2) Note that MathWorld's definition starts with unity, not zero.   This task will be using the OEIS' version   (above). An observation   fusc(A) = fusc(B) where   A   is some non-negative integer expressed in binary,   and where   B   is the binary value of   A   reversed. Fusc numbers are also known as:   fusc function   (named by Dijkstra, 1982)   Stern's Diatomic series   (although it starts with unity, not zero)   Stern-Brocot sequence   (although it starts with unity, not zero) Task   show the first   61   fusc numbers (starting at zero) in a horizontal format.   show the fusc number (and its index) whose length is greater than any previous fusc number length.   (the length is the number of decimal digits when the fusc number is expressed in base ten.)   show all numbers with commas   (if appropriate).   show all output here. Related task   RosettaCode Stern-Brocot sequence Also see   the MathWorld entry:   Stern's Diatomic Series.   the OEIS entry:   A2487.
#CLU
CLU
fusc = iter () yields (int) q: array[int] := array[int]$[1] yield(0) yield(1)   while true do x: int := array[int]$reml(q) array[int]$addh(q,x) yield(x)   x := x + array[int]$bottom(q) array[int]$addh(q,x) yield(x) end end fusc   longest_fusc = iter () yields (int,int) sofar: int := 0 count: int := 0   for f: int in fusc() do if f >= sofar then yield (count,f) sofar := 10*sofar if sofar=0 then sofar:=10 end end count := count + 1 end end longest_fusc   start_up = proc () po: stream := stream$primary_output()   stream$putl(po, "First 61:") n: int := 0 for f: int in fusc() do stream$puts(po, int$unparse(f) || " ") n := n + 1 if n = 61 then break end end   stream$putl(po, "\nLength records:") n := 0 for i, f: int in longest_fusc() do stream$putl(po, "fusc(" || int$unparse(i) || ") = " || int$unparse(f)) n := n + 1 if n = 5 then break end end end start_up
http://rosettacode.org/wiki/Fusc_sequence
Fusc sequence
Definitions The   fusc   integer sequence is defined as:   fusc(0) = 0   fusc(1) = 1   for n>1,   the   nth   term is defined as:   if   n   is even;     fusc(n) = fusc(n/2)   if   n   is   odd;     fusc(n) = fusc((n-1)/2)   +   fusc((n+1)/2) Note that MathWorld's definition starts with unity, not zero.   This task will be using the OEIS' version   (above). An observation   fusc(A) = fusc(B) where   A   is some non-negative integer expressed in binary,   and where   B   is the binary value of   A   reversed. Fusc numbers are also known as:   fusc function   (named by Dijkstra, 1982)   Stern's Diatomic series   (although it starts with unity, not zero)   Stern-Brocot sequence   (although it starts with unity, not zero) Task   show the first   61   fusc numbers (starting at zero) in a horizontal format.   show the fusc number (and its index) whose length is greater than any previous fusc number length.   (the length is the number of decimal digits when the fusc number is expressed in base ten.)   show all numbers with commas   (if appropriate).   show all output here. Related task   RosettaCode Stern-Brocot sequence Also see   the MathWorld entry:   Stern's Diatomic Series.   the OEIS entry:   A2487.
#D
D
import std.functional, std.stdio, std.format, std.conv;   ulong fusc(ulong n) => memoize!fuscImp(n);   ulong fuscImp(ulong n) => ( n < 2 ) ? n : ( n % 2 == 0 ) ? memoize!fuscImp( n/2 ) : memoize!fuscImp( (n-1)/2 ) + memoize!fuscImp( (n+1)/2 );   void main() { const N_FIRST=61; const MAX_N_DIGITS=5;   format!"First %d fusc numbers: "(N_FIRST).write; foreach( n; 0..N_FIRST ) n.fusc.format!"%d ".write; writeln;   format!"\nFusc numbers with more digits than any previous (1 to %d digits):"(MAX_N_DIGITS).writeln; for(auto n=0, ndigits=0; ndigits<MAX_N_DIGITS; n++) if( n.fusc.to!string.length > ndigits ){ format!"fusc(%d)=%d"( n, n.fusc ).writeln; ndigits = n.fusc.to!string.length.to!int; } }
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Racket
Racket
  #lang racket (require math) (define in (open-input-file "function-frequency.rkt")) (void (read-language in)) (define s-exprs (for/list ([s (in-port read in)]) s)) (define symbols (filter symbol? (flatten s-exprs))) (define counts (sort (hash->list (samples->hash symbols)) >= #:key cdr)) (take counts (min 10 (length counts)))  
http://rosettacode.org/wiki/Function_frequency
Function frequency
Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred). This is a static analysis: The question is not how often each function is actually executed at runtime, but how often it is used by the programmer. Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.
#Raku
Raku
my $text = qqx[raku --target=ast @*ARGS[]]; my %fun; for $text.lines { %fun{$0}++ if / '(call &' (.*?) ')' / }   for %fun.invert.sort.reverse[^10] { .value.say }
http://rosettacode.org/wiki/Gamma_function
Gamma function
Task Implement one algorithm (or more) to compute the Gamma ( Γ {\displaystyle \Gamma } ) function (in the real field only). If your language has the function as built-in or you know a library which has it, compare your implementation's results with the results of the built-in/library function. The Gamma function can be defined as: Γ ( x ) = ∫ 0 ∞ t x − 1 e − t d t {\displaystyle \Gamma (x)=\displaystyle \int _{0}^{\infty }t^{x-1}e^{-t}dt} This suggests a straightforward (but inefficient) way of computing the Γ {\displaystyle \Gamma } through numerical integration. Better suggested methods: Lanczos approximation Stirling's approximation
#Common_Lisp
Common Lisp
; Taylor series coefficients (defconstant tcoeff '( 1.00000000000000000000 0.57721566490153286061 -0.65587807152025388108 -0.04200263503409523553 0.16653861138229148950 -0.04219773455554433675 -0.00962197152787697356 0.00721894324666309954 -0.00116516759185906511 -0.00021524167411495097 0.00012805028238811619 -0.00002013485478078824 -0.00000125049348214267 0.00000113302723198170 -0.00000020563384169776 0.00000000611609510448 0.00000000500200764447 -0.00000000118127457049 0.00000000010434267117 0.00000000000778226344 -0.00000000000369680562 0.00000000000051003703 -0.00000000000002058326 -0.00000000000000534812 0.00000000000000122678 -0.00000000000000011813 0.00000000000000000119 0.00000000000000000141 -0.00000000000000000023 0.00000000000000000002))   ; number of coefficients (defconstant numcoeff (length tcoeff))   (defun gamma (x) (let ((y (- x 1.0)) (sum (nth (- numcoeff 1) tcoeff))) (loop for i from (- numcoeff 2) downto 0 do (setf sum (+ (* sum y) (nth i tcoeff)))) (/ 1.0 sum)))   (loop for i from 1 to 10 do ( format t "~12,10f~%" (gamma (/ i 3.0))))
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#Julia
Julia
using Random function drawball(timer) global r, c, d print("\e[$r;$(c)H ") # clear last ball position (r,c) if (r+=1) > 14 close(timer) b = (bin[(c+2)>>2] += 1)# update count in bin print("\e[$b;$(c)Ho") # lengthen bar of balls in bin else r in 3:2:13 && c in 17-r:4:11+r && (d = 2bitrand()-1) print("\e[$r;$(c+=d)Ho")# show ball moving in direction d end end   print("\e[2J") # clear screen for r = 3:2:13, c = 17-r:4:11+r # 6 pins in 6 rows print("\e[$r;$(c)H^") # draw pins end print("\e[15;2H-------------------------")   bin = fill(15,7) # positions of top of bins while "x" != readline() >= "" # x-Enter: exit, {keys..}Enter: next ball global r,c,d = 0,14,0 t = Timer(drawball, 0, interval=0.1) while r < 15 sleep(0.01) end print("\e[40;1H") # move cursor far down end
http://rosettacode.org/wiki/Galton_box_animation
Galton box animation
Example of a Galton Box at the end of animation. A   Galton device   Sir Francis Galton's device   is also known as a   bean machine,   a   Galton Board,   or a   quincunx. Description of operation In a Galton box, there are a set of pins arranged in a triangular pattern.   A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin.   The ball continues to fall to the left or right of lower pins before arriving at one of the collection points between and to the sides of the bottom row of pins. Eventually the balls are collected into bins at the bottom   (as shown in the image),   the ball column heights in the bins approximate a   bell curve.   Overlaying   Pascal's triangle   onto the pins shows the number of different paths that can be taken to get to each bin. Task Generate an animated simulation of a Galton device. Task requirements   The box should have at least 5 pins on the bottom row.   A solution can use graphics or ASCII animation.   Provide a sample of the output/display such as a screenshot.   There can be one or more balls in flight at the same time.   If multiple balls are in flight, ensure they don't interfere with each other.   A solution should allow users to specify the number of balls, or it should run until full or a preset limit.   Optionally,   display the number of balls.
#Kotlin
Kotlin
// version 1.2.10   import java.util.Random   val boxW = 41 // Galton box width. val boxH = 37 // Galton box height. val pinsBaseW = 19 // Pins triangle base. val nMaxBalls = 55 // Number of balls.   val centerH = pinsBaseW + (boxW - pinsBaseW * 2 + 1) / 2 - 1 val rand = Random()   enum class Cell(val c: Char) { EMPTY(' '), BALL('o'), WALL('|'), CORNER('+'), FLOOR('-'), PIN('.') }   /* Galton box. Will be printed upside down. */ val box = List(boxH) { Array<Cell>(boxW) { Cell.EMPTY } }   class Ball(var x: Int, var y: Int) {   init { require(box[y][x] == Cell.EMPTY) box[y][x] = Cell.BALL }   fun doStep() { if (y <= 0) return // Reached the bottom of the box. val cell = box[y - 1][x] when (cell) { Cell.EMPTY -> { box[y][x] = Cell.EMPTY y-- box[y][x] = Cell.BALL }   Cell.PIN -> { box[y][x] = Cell.EMPTY y-- if (box[y][x - 1] == Cell.EMPTY && box[y][x + 1] == Cell.EMPTY) { x += rand.nextInt(2) * 2 - 1 box[y][x] = Cell.BALL return } else if (box[y][x - 1] == Cell.EMPTY) x++ else x-- box[y][x] = Cell.BALL }   else -> { // It's frozen - it always piles on other balls. } } } }   fun initializeBox() { // Set ceiling and floor: box[0][0] = Cell.CORNER box[0][boxW - 1] = Cell.CORNER for (i in 1 until boxW - 1) box[0][i] = Cell.FLOOR for (i in 0 until boxW) box[boxH - 1][i] = box[0][i]   // Set walls: for (r in 1 until boxH - 1) { box[r][0] = Cell.WALL box[r][boxW - 1] = Cell.WALL }   // Set pins: for (nPins in 1..pinsBaseW) { for (pin in 0 until nPins) { box[boxH - 2 - nPins][centerH + 1 - nPins + pin * 2] = Cell.PIN } } }   fun drawBox() { for (row in box.reversed()) { for (i in row.indices) print(row[i].c) println() } }   fun main(args: Array<String>) { initializeBox() val balls = mutableListOf<Ball>() for (i in 0 until nMaxBalls + boxH) { println("\nStep $i:") if (i < nMaxBalls) balls.add(Ball(centerH, boxH - 2)) // Add ball. drawBox()   // Next step for the simulation. // Frozen balls are kept in balls list for simplicity for (b in balls) b.doStep() } }
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#JavaScript
JavaScript
// Function to construct a new integer from the first and last digits of another function gapfulness_divisor (number) { var digit_string = number.toString(10) var digit_count = digit_string.length var first_digit = digit_string.substring(0, 1) var last_digit = digit_string.substring(digit_count - 1) return parseInt(first_digit.concat(last_digit), 10) }   // Divisibility test to determine gapfulness function is_gapful (number) { return number % gapfulness_divisor(number) == 0 }   // Function to search for the least gapful number greater than a given integer function next_gapful (number) { do { ++number } while (!is_gapful(number)) return number }   // Constructor for a list of gapful numbers starting from given lower bound function gapful_numbers (start, amount) { var list = [], count = 0, number = start if (amount > 0 && is_gapful(start)) { list.push(start) } while (list.length < amount) { number = next_gapful(number) list.push(number) } return list }   // Formatter for a comma-separated list of gapful numbers function single_line_gapfuls (start, amount) { var list = gapful_numbers(start, amount) return list.join(", ") }   // Windows console output wrapper function print(message) { WScript.StdOut.WriteLine(message) }   // Main algorithm   function print_gapfuls_with_header(start, amount) { print("First " + start + " gapful numbers starting at " + amount) print(single_line_gapfuls(start, amount)) }   print_gapfuls_with_header(100, 30) print_gapfuls_with_header(1000000, 15) print_gapfuls_with_header(1000000000, 10)
http://rosettacode.org/wiki/Gaussian_elimination
Gaussian elimination
Task Solve   Ax=b   using Gaussian elimination then backwards substitution. A   being an   n by n   matrix. Also,   x and b   are   n by 1   vectors. To improve accuracy, please use partial pivoting and scaling. See also   the Wikipedia entry:   Gaussian elimination
#jq
jq
def ta: [ [1.00, 0.00, 0.00, 0.00, 0.00, 0.00], [1.00, 0.63, 0.39, 0.25, 0.16, 0.10], [1.00, 1.26, 1.58, 1.98, 2.49, 3.13], [1.00, 1.88, 3.55, 6.70, 12.62, 23.80], [1.00, 2.51, 6.32, 15.88, 39.90, 100.28], [1.00, 3.14, 9.87, 31.01, 97.41, 306.02] ];   def tb:[-0.01, 0.61, 0.91, 0.99, 0.60, 0.02];   # Expected values: def tx:[ -0.01, 1.602790394502114, -1.6132030599055613, 1.2454941213714368, -0.4909897195846576, 0.065760696175232 ];   # Input: an array or an object def swap($i;$j): .[$i] as $tmp | .[$i] = .[$j] | .[$j] = $tmp;   def gaussPartial(a0; b0): (b0|length) as $m | reduce range(0;a0|length) as $i ( { a: [range(0;$m)|null] }; .a[$i] = a0[$i] + [b0[$i]] ) | reduce range(0; .a|length) as $k (.; .iMax = 0 | .max = -1 | reduce range($k;$m) as $i (.; .a[$i] as $row # compute scale factor s = max abs in row | .s = -1 | reduce range($k;$m) as $j (.; ($row[$j]|length) as $e | if ($e > .s) then .s = $e else . end ) # scale the abs used to pick the pivot | ( ($row[$k]|length) / .s) as $abs | if $abs > .max then .iMax = $i | .max = $abs else . end ) | if (.a[.iMax][$k] == 0) then "Matrix is singular." | error else .iMax as $iMax | .a |= swap($k; $iMax) | reduce range($k + 1; $m) as $i (.; reduce range($k + 1; $m + 1 ) as $j (.; .a[$i][$j] = .a[$i][$j] - (.a[$k][$j] * .a[$i][$k] / .a[$k][$k]) ) | .a[$i][$k] = 0 ) end ) | .x = [range(0;$m)|0] | reduce range($m - 1; -1; -1) as $i (.; .x[$i] = .a[$i][$m] | reduce range($i + 1; $m) as $j (.; .x[$i] = .x[$i] - .a[$i][$j] * .x[$j] ) | .x[$i] = .x[$i] / .a[$i][$i] ) | .x ;   def x: gaussPartial(ta; tb);   # Input: the array of values to be compared againt $target def pointwise_check($target; $EPSILON): . as $x | range(0; $x|length) as $i | select( ($target[$i] - $x[$i])|length > $EPSILON ) | "\($x[$i]) vs expected value \($target[$i])" ;   def task: x | ., pointwise_check(tx; 1E-14) ;   task    
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#PL.2FI
PL/I
/* Gauss-Jordan matrix inversion */ G_J: procedure options (main); /* 4 November 2020 */ declare t float; declare (i, j, k, n) fixed binary; open file (sysin) title ('/GAUSSJOR.DAT'); get (n); /* Read in the order of the matrix. */ put skip data (n); begin; declare a(n,n)float, aux(n,n) float; aux = 0; do i = 1 to n; aux(i,i) = 1; end; get (a); /* Read in the matrix. */ put skip list ('The matrix to be inverted is:'); put edit (a) ( skip, (n) F(10,4)); /* Print the matrix. */ do k = 1 to n; /* Divide row k by a(k,k) */ t = a(k,k); a(k,*) = a(k,*) / t; aux(k,*) = aux(k,*) / t; do i = 1 to k-1, k+1 to n; /* Work down the rows. */ t = a(i,k); a(i,*) = a(i,*) - t*a(k,*); aux(i,*) = aux(i,*) - t*aux(k,*); end; end; put skip (2) list ('The inverse is:'); put edit (aux) ( skip, (n) F(10,4)); end; /* of BEGIN block */ end G_J;
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#PowerShell
PowerShell
  function gauss-jordan-inv([double[][]]$a) { $n = $a.count [double[][]]$b = 0..($n-1) | foreach{[double[]]$row = @(0) * $n; $row[$_] = 1; ,$row} for ($k = 0; $k -lt $n; $k++) { $lmax, $max = $k, [Math]::Abs($a[$k][$k]) for ($l = $k+1; $l -lt $n; $l++) { $tmp = [Math]::Abs($a[$l][$k]) if($max -lt $tmp) { $max, $lmax = $tmp, $l } } if ($k -ne $lmax) { $a[$k], $a[$lmax] = $a[$lmax], $a[$k] $b[$k], $b[$lmax] = $b[$lmax], $b[$k] } $akk = $a[$k][$k] if (0 -eq $akk) {throw "Irregular matrix"} for ($j = 0; $j -lt $n; $j++) { $a[$k][$j] /= $akk $b[$k][$j] /= $akk } for ($i = 0; $i -lt $n; $i++){ if ($i -ne $k) { $aik = $a[$i][$k] for ($j = 0; $j -lt $n; $j++) { $a[$i][$j] -= $a[$k][$j]*$aik $b[$i][$j] -= $b[$k][$j]*$aik } } } } $b } function show($a) { $a | foreach{ "$_"} }   $a = @(@(@(1, 2, 3), @(4, 1, 6), @(7, 8, 9))) $inva = gauss-jordan-inv $a "a =" show $a "" "inv(a) =" show $inva ""   $b = @(@(2, -1, 0), @(-1, 2, -1), @(0, -1, 2)) "b =" show $b "" $invb = gauss-jordan-inv $b "inv(b) =" show $invb    
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#OCaml
OCaml
  (* Task : General_FizzBuzz *)   (* The FizzBuzz problem, but generalized to have any strings, at any steps, up to any number of iterations. *)   let gen_fizz_buzz (n : int) (l : (int * string) list) : unit = let fold_f i (acc : bool) (k, s) = if i mod k = 0 then (print_string s; true) else acc in let rec helper i = if i > n then () else let any_printed = List.fold_left (fold_f i) false l in begin (if not any_printed then print_int i); print_newline (); helper (succ i) end in helper 1 ;;   (*** Output ***)   gen_fizz_buzz 20 [(3, "Fizz"); (5, "Buzz"); (7, "Baxx")] ;;