task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k |
|---|---|---|---|---|---|
http://rosettacode.org/wiki/Check_output_device_is_a_terminal | Check output device is a terminal | Task
Demonstrate how to check whether the output device is a terminal or not.
Related task
Check input device is a terminal
| #zkl | zkl | const S_IFCHR=0x2000;
fcn S_ISCHR(f){ f.info()[4].bitAnd(S_IFCHR).toBool() }
S_ISCHR(File.stdout).println(); |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #8086_Assembly | 8086 Assembly | cpu 8086
bits 16
vmode: equ 0Fh ; Get current video mode
time: equ 2Ch ; Get current system time
CGALO: equ 4 ; Low-res (4-color) CGA mode
MDA: equ 7 ; MDA text mode
section .text
org 100h
mov ah,vmode ; Get current video mode
int 10h
cmp al,MDA ; If MDA mode, no CGA supported, so stop
jne gr_ok
ret
gr_ok:... |
http://rosettacode.org/wiki/Chat_server | Chat server | Task
Write a server for a minimal text based chat.
People should be able to connect via ‘telnet’, sign on with a nickname, and type messages which will then be seen by all other connected users. Arrivals and departures of chat members should generate appropriate notification messages.
| #C | C | #include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <netinet/ip.h>
int tsocket;
struct sockaddr_in tsockinfo;
fd_set status, current;
void ClientText(int handle, char *buf, int buf_len);
struct client
{
char buffer[4096];
int pos;
char ... |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #Factor | Factor | USING: combinators formatting kernel locals math sequences ;
IN: rosetta-code.machin
: tan+ ( x y -- z ) [ + ] [ * 1 swap - / ] 2bi ;
:: tan-eval ( coef frac -- x )
{
{ [ coef zero? ] [ 0 ] }
{ [ coef neg? ] [ coef neg frac tan-eval neg ] }
{ [ coef odd? ] [ frac coef 1 - frac tan-eval t... |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #FreeBASIC | FreeBASIC | ' version 07-04-2018
' compile with: fbc -s console
#Include "gmp.bi"
#Define _a(Q) (@(Q)->_mp_num) 'a
#Define _b(Q) (@(Q)->_mp_den) 'b
Data "[1, 1, 2] [1, 1, 3]"
Data "[2, 1, 3] [1, 1, 7]"
Data "[4, 1, 5] [-1, 1, 239]"
Data "[5, 1, 7] [2, 3, 79]"
Data "[1, 1, 2] [1, 1, 5] [1, 1, 8]"
Data "[4, 1, 5] [-1, 1, 70]... |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #ActionScript | ActionScript | trace(String.fromCharCode(97)); //prints 'a'
trace("a".charCodeAt(0));//prints '97' |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #Ada | Ada | with Ada.Text_IO; use Ada.Text_IO;
procedure Char_Code is
begin
Put_Line (Character'Val (97) & " =" & Integer'Image (Character'Pos ('a')));
end Char_Code; |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Fantom | Fantom | **
** Cholesky decomposition
**
class Main
{
// create an array of Floats, initialised to 0.0
Float[][] makeArray (Int i, Int j)
{
Float[][] result := [,]
i.times { result.add ([,]) }
i.times |Int x|
{
j.times
{
result[x].add(0f)
}
}
return result
}
// pe... |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Fortran | Fortran | Program Cholesky_decomp
! *************************************************!
! LBH @ ULPGC 06/03/2014
! Compute the Cholesky decomposition for a matrix A
! after the attached
! http://rosettacode.org/wiki/Cholesky_decomposition
! note that the matrix A is complex since there might
! be values, where the sqrt has compl... |
http://rosettacode.org/wiki/Cheryl%27s_birthday | Cheryl's birthday | Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells Albert the month of birth, ... | #D | D | import std.algorithm.iteration : filter, joiner, map;
import std.algorithm.searching : canFind;
import std.algorithm.sorting : sort;
import std.array : array;
import std.datetime.date : Date, Month;
import std.stdio : writeln;
void main() {
auto choices = [
// Month.jan
Date(2019, Month.may, 15),
... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Java | Java | import java.util.Scanner;
import java.util.Random;
public class CheckpointSync{
public static void main(String[] args){
System.out.print("Enter number of workers to use: ");
Scanner in = new Scanner(System.in);
Worker.nWorkers = in.nextInt();
System.out.print("Enter number of tasks to complete:");
runTasks... |
http://rosettacode.org/wiki/Collections | Collections | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Collections are abstractions to represent sets of values.
In statically-typed languages, the values are typically of a common data type.
Task
Create a collection, and add a fe... | #Groovy | Groovy | def emptyList = []
assert emptyList.isEmpty() : "These are not the items you're looking for"
assert emptyList.size() == 0 : "Empty list has size 0"
assert ! emptyList : "Empty list evaluates as boolean 'false'"
def initializedList = [ 1, "b", java.awt.Color.BLUE ]
assert initializedList.size() == 3
assert initialized... |
http://rosettacode.org/wiki/Combinations | Combinations | Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
... | #Maxima | Maxima | next_comb(n, p, a) := block(
[a: copylist(a), i: p],
if a[1] + p = n + 1 then return(und),
while a[i] - i >= n - p do i: i - 1,
a[i]: a[i] + 1,
for j from i + 1 thru p do a[j]: a[j - 1] + 1,
a
)$
combinations(n, p) := block(
[a: makelist(i, i, 1, p), v: [ ]],
while a # 'und do (v: endcons(a, v... |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include ... | #Retro | Retro | condition [ true statements ] if
condition [ false statements ] -if
condition [ true statements ] [ false statements ] choose |
http://rosettacode.org/wiki/Chinese_remainder_theorem | Chinese remainder theorem | Suppose
n
1
{\displaystyle n_{1}}
,
n
2
{\displaystyle n_{2}}
,
…
{\displaystyle \ldots }
,
n
k
{\displaystyle n_{k}}
are positive integers that are pairwise co-prime.
Then, for any given sequence of integers
a
1
{\displaystyle a_{1}}
,
a
2
... | #Delphi | Delphi |
program ChineseRemainderTheorem;
uses
System.SysUtils, Velthuis.BigIntegers;
function mulInv(a, b: BigInteger): BigInteger;
var
b0, x0, x1, q, amb, xqx: BigInteger;
begin
b0 := b;
x0 := 0;
x1 := 1;
if (b = 1) then
exit(1);
while (a > 1) do
begin
q := a div b;
amb := a mod b;
a ... |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #jq | jq | def add(stream): reduce stream as $x (0; . + $x);
# input should be an integer
def commatize:
def digits: tostring | explode | reverse;
if . == null then ""
elif . < 0 then "-" + ((- .) | commatize)
else [foreach digits[] as $d (-1; .+1;
# "," is 44
(select(. > 0 and . % 3 == 0)|44), $d)... |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #Julia | Julia | using Primes, Formatting
function chowla(n)
if n < 1
throw("Chowla function argument must be positive")
elseif n < 4
return zero(n)
else
f = [one(n)]
for (p,e) in factor(n)
f = reduce(vcat, [f*p^j for j in 1:e], init=f)
end
return sum(f) - one(n)... |
http://rosettacode.org/wiki/Church_numerals | Church numerals | Task
In the Church encoding of natural numbers, the number N is encoded by a function that applies its first argument N times to its second argument.
Church zero always returns the identity function, regardless of its first argument. In other words, the first argument is not applied to the second argument at all.
C... | #Prolog | Prolog | church_zero(z).
church_successor(Z, c(Z)).
church_add(z, Z, Z).
church_add(c(X), Y, c(Z)) :-
church_add(X, Y, Z).
church_multiply(z, _, z).
church_multiply(c(X), Y, R) :-
church_add(Y, S, R),
church_multiply(X, Y, S).
% N ^ M
church_power(z, z, z).
church_power(N, c(z), N).
church_power(N, c(c(Z)), ... |
http://rosettacode.org/wiki/Classes | Classes | In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the class.
A class of types itself, a... | #GLSL | GLSL |
struct Rectangle{
float width;
float height;
};
Rectangle new(float width,float height){
Rectangle self;
self.width = width;
self.height = height;
return self;
}
float area(Rectangle self){
return self.width*self.height;
}
float perimeter(Rectangle self){
return (self.width+self.... |
http://rosettacode.org/wiki/Closest-pair_problem | Closest-pair problem |
This page uses content from Wikipedia. The original article was at Closest pair of points problem. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Provide a function to find the closest two p... | #Julia | Julia | function closestpair(P::Vector{Vector{T}}) where T <: Number
N = length(P)
if N < 2 return (Inf, ()) end
mindst = norm(P[1] - P[2])
minpts = (P[1], P[2])
for i in 1:N-1, j in i+1:N
tmpdst = norm(P[i] - P[j])
if tmpdst < mindst
mindst = tmpdst
minpts = (P[i], P... |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #R | R |
# assign 's' a list of ten functions
s <- sapply (1:10, # integers 1..10 become argument 'x' below
function (x) {
x # force evaluation of promise x
function (i=x) i*i # this *function* is the return value
})
s[[5]]() # call the fifth function in the list of returned functions
[1] 25 # re... |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Racket | Racket |
#lang racket
(define functions (for/list ([i 10]) (λ() (* i i))))
(map (λ(f) (f)) functions)
|
http://rosettacode.org/wiki/Circles_of_given_radius_through_two_points | Circles of given radius through two points |
Given two points on a plane and a radius, usually two circles of given radius can be drawn through the points.
Exceptions
r==0.0 should be treated as never describing circles (except in the case where the points are coincident).
If the points are coincident then an infinite number of circles with the point on thei... | #Factor | Factor | USING: accessors combinators combinators.short-circuit
formatting io kernel literals locals math math.distances
math.functions prettyprint sequences strings ;
IN: rosetta-code.circles
DEFER: find-circles
! === Input ====================================================
TUPLE: input p1 p2 r ;
CONSTANT: test-cases {... |
http://rosettacode.org/wiki/Chinese_zodiac | Chinese zodiac | Traditionally, the Chinese have counted years using two simultaneous cycles, one of length 10 (the "celestial stems") and one of length 12 (the "terrestrial branches"); the combination results in a repeating 60-year pattern. Mapping the branches to twelve traditional animal deities results in the well-known "Chinese zo... | #Delphi | Delphi |
program Chinese_zodiac;
{$APPTYPE CONSOLE}
uses
Winapi.Windows,
System.SysUtils,
System.Math;
type
TElements = array of array of char;
TChineseZodiac = record
Year: Integer;
Yyear: string;
Animal: string;
Element: string;
AnimalChar: char;
ElementChar: char;
procedure Ass... |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #Arturo | Arturo | checkIfExists: function [fpath][
(or? exists? fpath
exists? .directory fpath)? -> print [fpath "exists"]
-> print [fpath "doesn't exist"]
]
checkIfExists "input.txt"
checkIfExists "docs"
checkIfExists "/input.txt"
checkIfExists "/docs" |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #AutoHotkey | AutoHotkey | ; FileExist() function examples
ShowFileExist("input.txt")
ShowFileExist("\input.txt")
ShowFolderExist("docs")
ShowFolderExist("\docs")
; IfExist/IfNotExist command examples (from documentation)
IfExist, D:\
MsgBox, The drive exists.
IfExist, D:\Docs\*.txt
MsgBox, At least one .txt file exists.
IfNotExist, C:\Tem... |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #Action.21 | Action! | PROC Main()
INT x,w=[220],h=[190]
BYTE y,i,CH=$02FC,COLOR1=$02C5,COLOR2=$02C6
Graphics(8+16)
Color=1
COLOR1=$0C
COLOR2=$02
x=Rand(w)
y=Rand(h)
DO
i=Rand(3)
IF i=0 THEN
x==/2
y==/2
ELSEIF i=1 THEN
x=w/2+(w/2-x)/2
y=h-(h-y)/2
ELSE
x=w-(w-x)/2
y=y/2... |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #Amazing_Hopper | Amazing Hopper |
/* Chaos game - JAMBO hopper */
#include <jambo.h>
#define LIMITE 50000
Main
ancho = 700, alto = 150
x=0,y=0,color=0
vertice=0,
c=0, Let( c := Utf8(Chr(219)))
Let(x := Int(Rand(ancho)))
Let(y := Int(Rand(alto)))
mid ancho=0, Let( mid ancho:= Div(ancho,2))
i=LIMITE
Void(pixeles)
Loop
... |
http://rosettacode.org/wiki/Chat_server | Chat server | Task
Write a server for a minimal text based chat.
People should be able to connect via ‘telnet’, sign on with a nickname, and type messages which will then be seen by all other connected users. Arrivals and departures of chat members should generate appropriate notification messages.
| #C.23 | C# | using System;
using System.Collections.Generic;
using System.Net.Sockets;
using System.Text;
using System.Threading;
namespace ChatServer {
class State {
private TcpClient client;
private StringBuilder sb = new StringBuilder();
public string Name { get; }
public State(string na... |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #GAP | GAP | TanPlus := function(a, b)
return (a + b) / (1 - a * b);
end;
TanTimes := function(n, a)
local x;
x := 0;
while n > 0 do
if IsOddInt(n) then
x := TanPlus(x, a);
fi;
a := TanPlus(a, a);
n := QuoInt(n, 2);
od;
return x;
end;
Check := function(a)
l... |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #Go | Go | package main
import (
"fmt"
"math/big"
)
type mTerm struct {
a, n, d int64
}
var testCases = [][]mTerm{
{{1, 1, 2}, {1, 1, 3}},
{{2, 1, 3}, {1, 1, 7}},
{{4, 1, 5}, {-1, 1, 239}},
{{5, 1, 7}, {2, 3, 79}},
{{1, 1, 2}, {1, 1, 5}, {1, 1, 8}},
{{4, 1, 5}, {-1, 1, 70}, {1, 1, 99}},
... |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #Aime | Aime | # prints "97"
o_integer('a');
o_byte('\n');
# prints "a"
o_byte(97);
o_byte('\n'); |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #ALGOL_68 | ALGOL 68 | main:(
printf(($gl$, ABS "a")); # for ASCII this prints "+97" EBCDIC prints "+129" #
printf(($gl$, REPR 97)) # for ASCII this prints "a"; EBCDIC prints "/" #
) |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #FreeBASIC | FreeBASIC | ' version 18-01-2017
' compile with: fbc -s console
Sub Cholesky_decomp(array() As Double)
Dim As Integer i, j, k
Dim As Double s, l(UBound(array), UBound(array, 2))
For i = 0 To UBound(array)
For j = 0 To i
s = 0
For k = 0 To j -1
s += l(i, k) * l(j, k)... |
http://rosettacode.org/wiki/Cheryl%27s_birthday | Cheryl's birthday | Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells Albert the month of birth, ... | #F.23 | F# |
//Find Cheryl's Birthday. Nigel Galloway: October 23rd., 2018
type Month = |May |June |July |August
let fN n= n |> List.filter(fun (_,n)->(List.length n) < 2) |> List.unzip
let dates = [(May,15);(May,16);(May,19);(June,17);(June,18);(July,14);(July,16);(August,14);(August,15);(August,17)]
let _,n = dates |> List.grou... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Julia | Julia |
function runsim(numworkers, runs)
for count in 1:runs
@sync begin
for worker in 1:numworkers
@async begin
tasktime = rand()
sleep(tasktime)
println("Worker $worker finished after $tasktime seconds")
end... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Kotlin | Kotlin | // Version 1.2.41
import java.util.Random
val rgen = Random()
var nWorkers = 0
var nTasks = 0
class Worker(private val threadID: Int) : Runnable {
@Synchronized
override fun run() {
try {
val workTime = rgen.nextInt(900) + 100L // 100..999 msec.
println("Worker $threadID... |
http://rosettacode.org/wiki/Collections | Collections | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Collections are abstractions to represent sets of values.
In statically-typed languages, the values are typically of a common data type.
Task
Create a collection, and add a fe... | #Haskell | Haskell | [1, 2, 3, 4, 5] |
http://rosettacode.org/wiki/Combinations | Combinations | Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
... | #Modula-2 | Modula-2 |
MODULE Combinations;
FROM STextIO IMPORT
WriteString, WriteLn;
FROM SWholeIO IMPORT
WriteInt;
CONST
MMax = 3;
NMax = 5;
VAR
Combination: ARRAY [0 .. MMax] OF CARDINAL;
PROCEDURE Generate(M: CARDINAL);
VAR
N, I: CARDINAL;
BEGIN
IF (M > MMax) THEN
FOR I := 1 TO MMax DO
WriteInt(Combination... |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include ... | #REXX | REXX | if y then @=6 /* Y must be either 0 or 1 */
if t**2>u then x=y /*simple IF with THEN & ELSE. */
else x=-y
if t**2>u then do j=1 for 10; say prime(j); end /*THEN DO loop.*/
else x=-y /*simple ELSE.... |
http://rosettacode.org/wiki/Chinese_remainder_theorem | Chinese remainder theorem | Suppose
n
1
{\displaystyle n_{1}}
,
n
2
{\displaystyle n_{2}}
,
…
{\displaystyle \ldots }
,
n
k
{\displaystyle n_{k}}
are positive integers that are pairwise co-prime.
Then, for any given sequence of integers
a
1
{\displaystyle a_{1}}
,
a
2
... | #EasyLang | EasyLang | func mul_inv a b . x1 .
b0 = b
x1 = 1
if b <> 1
while a > 1
q = a div b
t = b
b = a mod b
a = t
t = x0
x0 = x1 - q * x0
x1 = t
.
if x1 < 0
x1 += b0
.
.
.
func remainder . n[] a[] r .
prod = 1
sum = 0
for i range len n[]
prod *= n[i]
.
... |
http://rosettacode.org/wiki/Chinese_remainder_theorem | Chinese remainder theorem | Suppose
n
1
{\displaystyle n_{1}}
,
n
2
{\displaystyle n_{2}}
,
…
{\displaystyle \ldots }
,
n
k
{\displaystyle n_{k}}
are positive integers that are pairwise co-prime.
Then, for any given sequence of integers
a
1
{\displaystyle a_{1}}
,
a
2
... | #EchoLisp | EchoLisp |
(lib 'math)
math.lib v1.10 ® EchoLisp
Lib: math.lib loaded.
(crt-solve '(2 3 2) '(3 5 7))
→ 23
(crt-solve '(2 3 2) '(7 1005 15))
💥 error: mod[i] must be co-primes : assertion failed : 1005
|
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #Kotlin | Kotlin | // Version 1.3.21
fun chowla(n: Int): Int {
if (n < 1) throw RuntimeException("argument must be a positive integer")
var sum = 0
var i = 2
while (i * i <= n) {
if (n % i == 0) {
val j = n / i
sum += if (i == j) i else i + j
}
i++
}
return sum
}
... |
http://rosettacode.org/wiki/Church_numerals | Church numerals | Task
In the Church encoding of natural numbers, the number N is encoded by a function that applies its first argument N times to its second argument.
Church zero always returns the identity function, regardless of its first argument. In other words, the first argument is not applied to the second argument at all.
C... | #Python | Python | '''Church numerals'''
from itertools import repeat
from functools import reduce
# ----- CHURCH ENCODINGS OF NUMERALS AND OPERATIONS ------
def churchZero():
'''The identity function.
No applications of any supplied f
to its argument.
'''
return lambda f: identity
def churchSucc(cn)... |
http://rosettacode.org/wiki/Classes | Classes | In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the class.
A class of types itself, a... | #Go | Go | package main
import "fmt"
// a basic "class."
// In quotes because Go does not use that term or have that exact concept.
// Go simply has types that can have methods.
type picnicBasket struct {
nServings int // "instance variables"
corkscrew bool
}
// a method (yes, Go uses the word method!)
func (b *picn... |
http://rosettacode.org/wiki/Closest-pair_problem | Closest-pair problem |
This page uses content from Wikipedia. The original article was at Closest pair of points problem. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Provide a function to find the closest two p... | #Kotlin | Kotlin | // version 1.1.2
typealias Point = Pair<Double, Double>
fun distance(p1: Point, p2: Point) = Math.hypot(p1.first- p2.first, p1.second - p2.second)
fun bruteForceClosestPair(p: List<Point>): Pair<Double, Pair<Point, Point>> {
val n = p.size
if (n < 2) throw IllegalArgumentException("Must be at least two po... |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Raku | Raku | my @c = gather for ^10 -> $i {
take { $i * $i }
}
.().say for @c.pick(*); # call them in random order |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Red | Red |
funs: collect [repeat i 10 [keep func [] reduce [i ** 2]]]
>> funs/7
== 49
|
http://rosettacode.org/wiki/Circles_of_given_radius_through_two_points | Circles of given radius through two points |
Given two points on a plane and a radius, usually two circles of given radius can be drawn through the points.
Exceptions
r==0.0 should be treated as never describing circles (except in the case where the points are coincident).
If the points are coincident then an infinite number of circles with the point on thei... | #Fortran | Fortran |
! Implemented by Anant Dixit (Nov. 2014)
! Transpose elements in find_center to obtain correct results. R.N. McLean (Dec 2017)
program circles
implicit none
double precision :: P1(2), P2(2), R
P1 = (/0.1234d0, 0.9876d0/)
P2 = (/0.8765d0,0.2345d0/)
R = 2.0d0
call print_centers(P1,P2,R)
P1 = (/0.0d0, 2.0d0/)
P2 = (... |
http://rosettacode.org/wiki/Chinese_zodiac | Chinese zodiac | Traditionally, the Chinese have counted years using two simultaneous cycles, one of length 10 (the "celestial stems") and one of length 12 (the "terrestrial branches"); the combination results in a repeating 60-year pattern. Mapping the branches to twelve traditional animal deities results in the well-known "Chinese zo... | #Excel | Excel | CNZODIAC
=LAMBDA(y,
APPENDCOLS(
APPENDCOLS(
APPENDCOLS(
CNYEARNAME(y)
)(
CNYEARELEMENT(y)
)
)(
CNYEARANIMAL(y)
)
)(
CNYEARYINYANG(y)
)
)
CNYEARANIMAL
=LAMBDA(y,
LET(
shengxiao, {
... |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #AWK | AWK | @load "filefuncs"
function exists(name ,fd) {
if ( stat(name, fd) == -1)
print name " doesn't exist"
else
print name " exists"
}
BEGIN {
exists("input.txt")
exists("/input.txt")
exists("docs")
exists("/docs")
} |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #Axe | Axe | If GetCalc("appvINPUT")
Disp "EXISTS",i
Else
Disp "DOES NOT EXIST",i
End |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #BASIC | BASIC | 10 SCREEN 1
20 X = INT(RND(0) * 200)
30 Y = INT(RND(0) * 173)
40 FOR I=1 TO 20000
50 V = INT(RND(0) * 3) + 1
60 ON V GOTO 70,100,130
70 X = X/2
80 Y = Y/2
90 GOTO 150
100 X = 100 + (100-X)/2
110 Y = 173 - (173-Y)/2
120 GOTO 150
130 X = 200 - (200-X)/2
140 Y = Y/2
150 PSET X,Y,V
160 NEXT I |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #C | C |
#include<graphics.h>
#include<stdlib.h>
#include<stdio.h>
#include<math.h>
#include<time.h>
#define pi M_PI
int main(){
time_t t;
double side, vertices[3][3],seedX,seedY,windowSide;
int i,iter,choice;
printf("Enter triangle side length : ");
scanf("%lf",&side);
printf("Enter number of iterations : ");... |
http://rosettacode.org/wiki/Chat_server | Chat server | Task
Write a server for a minimal text based chat.
People should be able to connect via ‘telnet’, sign on with a nickname, and type messages which will then be seen by all other connected users. Arrivals and departures of chat members should generate appropriate notification messages.
| #CoffeeScript | CoffeeScript |
net = require("net")
sys = require("sys")
EventEmitter = require("events").EventEmitter
isNicknameLegal = (nickname) ->
return false unless nickname.replace(/[A-Za-z0-9]*/, "") is ""
for used_nick of @chatters
return false if used_nick is nickname
true
class ChatServer
constructor: ->
@chatters = ... |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #Haskell | Haskell | import Data.Ratio
import Data.List (foldl')
tanPlus :: Fractional a => a -> a -> a
tanPlus a b = (a + b) / (1 - a * b)
tanEval :: (Integral a, Fractional b) => (a, b) -> b
tanEval (0,_) = 0
tanEval (coef,f)
| coef < 0 = -tanEval (-coef, f)
| odd coef = tanPlus f $ tanEval (coef - 1, f)
| otherwise = tanPlus a a
... |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #ALGOL_W | ALGOL W | begin
% display the character code of "a" (97 in ASCII) %
write( decode( "a" ) );
% display the character corresponding to 97 ("a" in ASCII) %
write( code( 97 ) );
end. |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #APL | APL | ⎕UCS 97
a |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Go | Go | package main
import (
"fmt"
"math"
)
// symmetric and lower use a packed representation that stores only
// the lower triangle.
type symmetric struct {
order int
ele []float64
}
type lower struct {
order int
ele []float64
}
// symmetric.print prints a square matrix from the packed ... |
http://rosettacode.org/wiki/Cheryl%27s_birthday | Cheryl's birthday | Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells Albert the month of birth, ... | #Factor | Factor | USING: assocs calendar.english fry io kernel prettyprint
sequences sets.extras ;
: unique-by ( seq quot -- newseq )
2dup map non-repeating '[ @ _ member? ] filter ; inline
ALIAS: day first
ALIAS: month second
{
{ 15 5 } { 16 5 } { 19 5 } { 17 6 } { 18 6 }
{ 14 7 } { 16 7 } { 14 8 } { 15 8 } { 17 8 }
}... |
http://rosettacode.org/wiki/Cheryl%27s_birthday | Cheryl's birthday | Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells Albert the month of birth, ... | #Go | Go | package main
import (
"fmt"
"time"
)
type birthday struct{ month, day int }
func (b birthday) String() string {
return fmt.Sprintf("%s %d", time.Month(b.month), b.day)
}
func (b birthday) monthUniqueIn(bds []birthday) bool {
count := 0
for _, bd := range bds {
if bd.month == b.month ... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Logtalk | Logtalk |
:- object(checkpoint).
:- threaded.
:- public(run/3).
:- mode(run(+integer,+integer,+float), one).
:- info(run/3, [
comment is 'Assemble items using a team of workers with a maximum time per item assembly.',
arguments is ['Workers'-'Number of workers', 'Items'-'Number of items to a... |
http://rosettacode.org/wiki/Collections | Collections | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Collections are abstractions to represent sets of values.
In statically-typed languages, the values are typically of a common data type.
Task
Create a collection, and add a fe... | #Icon_and_Unicon | Icon and Unicon | # Creation of collections:
s := "abccd" # string, an ordered collection of characters, immutable
c := 'abcd' # cset, an unordered collection of characters, immutable
S := set() # set, an unordered collection of... |
http://rosettacode.org/wiki/Combinations | Combinations | Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
... | #Nim | Nim | iterator comb(m, n: int): seq[int] =
var c = newSeq[int](n)
for i in 0 ..< n: c[i] = i
block outer:
while true:
yield c
var i = n - 1
inc c[i]
if c[i] <= m - 1: continue
while c[i] >= m - n + i:
dec i
if i < 0: break outer
inc c[i]
while i < n-1:... |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include ... | #Rhope | Rhope | If[cond]
|:
Do Something[]
:||:
Do Something Else[]
:| |
http://rosettacode.org/wiki/Chinese_remainder_theorem | Chinese remainder theorem | Suppose
n
1
{\displaystyle n_{1}}
,
n
2
{\displaystyle n_{2}}
,
…
{\displaystyle \ldots }
,
n
k
{\displaystyle n_{k}}
are positive integers that are pairwise co-prime.
Then, for any given sequence of integers
a
1
{\displaystyle a_{1}}
,
a
2
... | #Elixir | Elixir | defmodule Chinese do
def remainder(mods, remainders) do
max = Enum.reduce(mods, fn x,acc -> x*acc end)
Enum.zip(mods, remainders)
|> Enum.map(fn {m,r} -> Enum.take_every(r..max, m) |> MapSet.new end)
|> Enum.reduce(fn set,acc -> MapSet.intersection(set, acc) end)
|> MapSet.to_list
end
end
IO.i... |
http://rosettacode.org/wiki/Chinese_remainder_theorem | Chinese remainder theorem | Suppose
n
1
{\displaystyle n_{1}}
,
n
2
{\displaystyle n_{2}}
,
…
{\displaystyle \ldots }
,
n
k
{\displaystyle n_{k}}
are positive integers that are pairwise co-prime.
Then, for any given sequence of integers
a
1
{\displaystyle a_{1}}
,
a
2
... | #Erlang | Erlang | -module(crt).
-import(lists, [zip/2, unzip/1, foldl/3, sum/1]).
-export([egcd/2, mod/2, mod_inv/2, chinese_remainder/1]).
egcd(_, 0) -> {1, 0};
egcd(A, B) ->
{S, T} = egcd(B, A rem B),
{T, S - (A div B)*T}.
mod_inv(A, B) ->
{X, Y} = egcd(A, B),
if
A*X + B*Y =:= 1 -> X;
true -> undefi... |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #Lua | Lua | function chowla(n)
local sum = 0
local i = 2
local j = 0
while i * i <= n do
if n % i == 0 then
j = math.floor(n / i)
sum = sum + i
if i ~= j then
sum = sum + j
end
end
i = i + 1
end
return sum
end
function... |
http://rosettacode.org/wiki/Church_numerals | Church numerals | Task
In the Church encoding of natural numbers, the number N is encoded by a function that applies its first argument N times to its second argument.
Church zero always returns the identity function, regardless of its first argument. In other words, the first argument is not applied to the second argument at all.
C... | #Quackery | Quackery | [ this nested ] is zero ( --> cn )
[ this nested join ] is succ ( cn --> cn )
[ zero
[ 2dup = if done
succ
rot succ unrot
recurse ]
2drop ] is add ( cn cn --> cn )
[ zero unrot zero
[ 2dup = if done
succ
2swap
tuck... |
http://rosettacode.org/wiki/Classes | Classes | In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the class.
A class of types itself, a... | #Groovy | Groovy | /** Ye olde classe declaration */
class Stuff {
/** Heare bee anne instance variable declared */
def guts
/** This constructor converts bits into Stuff */
Stuff(injectedGuts) {
guts = injectedGuts
}
/** Brethren and sistren, let us flangulate with this fine flangulating method */
... |
http://rosettacode.org/wiki/Closest-pair_problem | Closest-pair problem |
This page uses content from Wikipedia. The original article was at Closest pair of points problem. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Provide a function to find the closest two p... | #Liberty_BASIC | Liberty BASIC |
N =10
dim x( N), y( N)
firstPt =0
secondPt =0
for i =1 to N
read f: x( i) =f
read f: y( i) =f
next i
minDistance =1E6
for i =1 to N -1
for j =i +1 to N
dxSq =( x( i) -x( j))^2
dySq =( y( i) -y( j))^2
D =abs( ( dxSq +dySq)^0.5)
if D <minDistance then
minDistan... |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #REXX | REXX | /*REXX program has a list of ten functions, each returns its invocation (index) squared.*/
parse arg seed base $ /*obtain optional arguments from the CL*/
if datatype(seed, 'W') then call random ,,seed /*Not given? Use random start seed. */
if base=='' | base="," then base=0 ... |
http://rosettacode.org/wiki/Circles_of_given_radius_through_two_points | Circles of given radius through two points |
Given two points on a plane and a radius, usually two circles of given radius can be drawn through the points.
Exceptions
r==0.0 should be treated as never describing circles (except in the case where the points are coincident).
If the points are coincident then an infinite number of circles with the point on thei... | #FreeBASIC | FreeBASIC | Type Point
As Double x,y
Declare Property length As Double
End Type
Property point.length As Double
Return Sqr(x*x+y*y)
End Property
Sub circles(p1 As Point,p2 As Point,radius As Double)
Print "Points ";"("&p1.x;","&p1.y;"),("&p2.x;","&p2.y;")";", Rad ";radius
Var ctr=Type<Point>((p1.x+p2.x)/2,(p1.y... |
http://rosettacode.org/wiki/Chinese_zodiac | Chinese zodiac | Traditionally, the Chinese have counted years using two simultaneous cycles, one of length 10 (the "celestial stems") and one of length 12 (the "terrestrial branches"); the combination results in a repeating 60-year pattern. Mapping the branches to twelve traditional animal deities results in the well-known "Chinese zo... | #F.23 | F# |
open System
let animals = ["Rat";"Ox";"Tiger";"Rabbit";"Dragon";"Snake";"Horse";"Goat";"Monkey";"Rooster";"Dog";"Pig"]
let elements = ["Wood";"Fire";"Earth";"Metal";"Water"]
let years = [1935;1938;1968;1972;1976;1984;1985;2017]
let getZodiac(year: int) =
let animal = animals.Item((year-4)%12)
let element... |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #BASIC | BASIC |
ON ERROR GOTO ohNo
f$ = "input.txt"
GOSUB opener
f$ = "\input.txt"
GOSUB opener
'can't directly check for directories,
'but can check for the NUL device in the desired dir
f$ = "docs\nul"
GOSUB opener
f$ = "\docs\nul"
GOSUB opener
END
opener:
e$ = " found"
OPEN f$ FOR INPUT AS 1
PRINT f$; e$
CLOSE... |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #C.23 | C# | using System.Diagnostics;
using System.Drawing;
namespace RosettaChaosGame
{
class Program
{
static void Main(string[] args)
{
var bm = new Bitmap(600, 600);
var referencePoints = new Point[] {
new Point(0, 600),
new Point(600, 600),
... |
http://rosettacode.org/wiki/Chat_server | Chat server | Task
Write a server for a minimal text based chat.
People should be able to connect via ‘telnet’, sign on with a nickname, and type messages which will then be seen by all other connected users. Arrivals and departures of chat members should generate appropriate notification messages.
| #D | D |
import std.getopt;
import std.socket;
import std.stdio;
import std.string;
struct client {
int pos;
char[] name;
char[] buffer;
Socket socket;
}
void broadcast(client[] connections, size_t self, const char[] message) {
writeln(message);
for (size_t i = 0; i < connections.length; i++) {
... |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #J | J | machin =: 1r4p1 = [: +/ ({. * _3 o. %/@:}.)"1@:x: |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #Java | Java |
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class CheckMachinFormula {
private static String FIL... |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #AppleScript | AppleScript | log(id of "a")
log(id of "aA") |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program character.s */
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/* Initialized data */
.data
szMessCodeChar: .ascii "The code of character is :"
sZoneconv: .fill 12,1,' '
szCarriageRet... |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Groovy | Groovy | def decompose = { a ->
assert a.size > 0 && a[0].size == a.size
def m = a.size
def l = [].withEagerDefault { [].withEagerDefault { 0 } }
(0..<m).each { i ->
(0..i).each { k ->
Number s = (0..<k).sum { j -> l[i][j] * l[k][j] } ?: 0
l[i][k] = (i == k)
... |
http://rosettacode.org/wiki/Cheryl%27s_birthday | Cheryl's birthday | Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells Albert the month of birth, ... | #Groovy | Groovy | import java.time.Month
class Main {
private static class Birthday {
private Month month
private int day
Birthday(Month month, int day) {
this.month = month
this.day = day
}
Month getMonth() {
return month
}
int getDa... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Nim | Nim | import locks
import os
import random
import strformat
const
NWorkers = 3 # Number of workers.
NTasks = 4 # Number of tasks.
StopOrder = 0 # Order 0 is the request to stop.
var
randLock: Lock # Lock to access random number generator.
orders: array[1..NWorkers, Channel... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Oforth | Oforth | : task(n, jobs, myChannel)
while(true) [
System.Out "TASK " << n << " : Beginning my work..." << cr
System sleep(1000 rand)
System.Out "TASK " << n << " : Finish, sendind done and waiting for others..." << cr
jobs send($jobDone) drop
myChannel receive drop
] ;
: checkPoint(n, jo... |
http://rosettacode.org/wiki/Checkpoint_synchronization | Checkpoint synchronization | The checkpoint synchronization is a problem of synchronizing multiple tasks. Consider a workshop where several workers (tasks) assembly details of some mechanism. When each of them completes his work they put the details together. There is no store, so a worker who finished its part first must wait for others before st... | #Perl | Perl | #!/usr/bin/perl
use warnings;
use strict;
use v5.10;
use Socket;
my $nr_items = 3;
sub short_sleep($) {
(my $seconds) = @_;
select undef, undef, undef, $seconds;
}
# This is run in a worker thread. It repeatedly waits for a character from
# the main thread, and sends a value back to the main thread. A... |
http://rosettacode.org/wiki/Collections | Collections | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Collections are abstractions to represent sets of values.
In statically-typed languages, the values are typically of a common data type.
Task
Create a collection, and add a fe... | #J | J | c =: 0 10 20 30 40 NB. A collection
c, 50 NB. Append 50 to the collection
0 10 20 30 40 50
_20 _10 , c NB. Prepend _20 _10 to the collection
_20 _10 0 10 20 30 40
,~ c NB. Self-append
0 10 20 30 40 0 10 20 30 40
,:~ c NB. Duplicate
0 10 20 30 40
0... |
http://rosettacode.org/wiki/Combinations | Combinations | Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
... | #OCaml | OCaml | let combinations m n =
let rec c = function
| (0,_) -> [[]]
| (_,0) -> []
| (p,q) -> List.append
(List.map (List.cons (n-q)) (c (p-1, q-1)))
(c (p , q-1))
in c (m , n)
let () =
let rec print_list = function
| [] -> print_newline ()
| hd :: tl -> print_int hd ;... |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include ... | #Ring | Ring | If x == 1
SomeFunc1()
But x == 2
SomeFunc2()
Else
SomeFunc()
Ok |
http://rosettacode.org/wiki/Chinese_remainder_theorem | Chinese remainder theorem | Suppose
n
1
{\displaystyle n_{1}}
,
n
2
{\displaystyle n_{2}}
,
…
{\displaystyle \ldots }
,
n
k
{\displaystyle n_{k}}
are positive integers that are pairwise co-prime.
Then, for any given sequence of integers
a
1
{\displaystyle a_{1}}
,
a
2
... | #F.23 | F# | let rec sieve cs x N =
match cs with
| [] -> Some(x)
| (a,n)::rest ->
let arrProgress = Seq.unfold (fun x -> Some(x, x+N)) x
let firstXmodNequalA = Seq.tryFind (fun x -> a = x % n)
match firstXmodNequalA (Seq.take n arrProgress) with
| None -> None
| Some(x) -> sieve ... |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #MAD | MAD | NORMAL MODE IS INTEGER
INTERNAL FUNCTION(N)
ENTRY TO CHOWLA.
SUM = 0
THROUGH LOOP, FOR I=2, 1, I*I.G.N
J = N/I
WHENEVER J*I.E.N
SUM = SUM + I
WHENEVER I.NE.J, SUM = SUM + J
END OF CONDITIONA... |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #Maple | Maple | ChowlaFunction := n -> NumberTheory:-SumOfDivisors(n) - n - 1;
PrintChowla := proc(n::posint) local i;
printf("Integer : Chowla Number\n");
for i to n do
printf("%d : %d\n", i, ChowlaFunction(i));
end do;
end proc:
countPrimes := n -> nops([ListTools[SearchAll](0, map(ChowlaFunction, [seq(1 .. n)]))]);
fin... |
http://rosettacode.org/wiki/Church_numerals | Church numerals | Task
In the Church encoding of natural numbers, the number N is encoded by a function that applies its first argument N times to its second argument.
Church zero always returns the identity function, regardless of its first argument. In other words, the first argument is not applied to the second argument at all.
C... | #R | R | zero <- function(f) {function(x) x}
succ <- function(n) {function(f) {function(x) f(n(f)(x))}}
add <- function(n) {function(m) {function(f) {function(x) m(f)(n(f)(x))}}}
mult <- function(n) {function(m) {function(f) m(n(f))}}
expt <- function(n) {function(m) m(n)}
natToChurch <- function(n) {if(n == 0) zero else succ(n... |
http://rosettacode.org/wiki/Classes | Classes | In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the class.
A class of types itself, a... | #Haskell | Haskell | class Shape a where
perimeter :: a -> Double
area :: a -> Double
{- A type class Shape. Types belonging to Shape must support two
methods, perimeter and area. -}
data Rectangle = Rectangle Double Double
{- A new type with a single constructor. In the case of data types
which have only one constructor, we... |
http://rosettacode.org/wiki/Closest-pair_problem | Closest-pair problem |
This page uses content from Wikipedia. The original article was at Closest pair of points problem. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Provide a function to find the closest two p... | #Maple | Maple | ClosestPair := module()
local
ModuleApply := proc(L::list,$)
local Lx, Ly, out;
Ly := sort(L, 'key'=(i->i[2]), 'output'='permutation');
Lx := sort(L, 'key'=(i->i[1]), 'output'='permutation');
out := Recurse(L, Lx, Ly, 1, numelems(L));
return sqrt(out[1]), out[2];
end proc; ... |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Ring | Ring |
x = funcs(7)
see x + nl
func funcs n
fn = list(n)
for i = 1 to n
fn[i] =i*i
next
return fn
|
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Ruby | Ruby | procs = Array.new(10){|i| ->{i*i} } # -> creates a lambda
p procs[7].call # => 49 |
http://rosettacode.org/wiki/Circles_of_given_radius_through_two_points | Circles of given radius through two points |
Given two points on a plane and a radius, usually two circles of given radius can be drawn through the points.
Exceptions
r==0.0 should be treated as never describing circles (except in the case where the points are coincident).
If the points are coincident then an infinite number of circles with the point on thei... | #Go | Go | package main
import (
"fmt"
"math"
)
var (
Two = "Two circles."
R0 = "R==0.0 does not describe circles."
Co = "Coincident points describe an infinite number of circles."
CoR0 = "Coincident points with r==0.0 describe a degenerate circle."
Diam = "Points form a diameter and describe ... |
http://rosettacode.org/wiki/Chinese_zodiac | Chinese zodiac | Traditionally, the Chinese have counted years using two simultaneous cycles, one of length 10 (the "celestial stems") and one of length 12 (the "terrestrial branches"); the combination results in a repeating 60-year pattern. Mapping the branches to twelve traditional animal deities results in the well-known "Chinese zo... | #Factor | Factor | USING: circular formatting io kernel math qw sequences
sequences.repeating ;
IN: rosetta-code.zodiac
<PRIVATE
! Offset start index by -4 because first cycle started on 4 CE.
: circularize ( seq -- obj )
[ -4 ] dip <circular> [ change-circular-start ] keep ;
: animals ( -- obj )
qw{
Rat Ox Tiger Ra... |
http://rosettacode.org/wiki/Chinese_zodiac | Chinese zodiac | Traditionally, the Chinese have counted years using two simultaneous cycles, one of length 10 (the "celestial stems") and one of length 12 (the "terrestrial branches"); the combination results in a repeating 60-year pattern. Mapping the branches to twelve traditional animal deities results in the well-known "Chinese zo... | #FreeBASIC | FreeBASIC | dim as string yy(0 to 1) = {"yang", "yin"}
dim as string elements(0 to 4) = {"Wood", "Fire", "Earth", "Metal", "Water"}
dim as string animals(0 to 11) = {"Rat", "Ox", "Tiger", "Rabbit", "Dragon", "Snake",_
"Horse", "Goat", "Monkey", "Rooster", "Dog", "Pig"}
dim as uinteger yr, y, e, ... |
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