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 | response_seed stringclasses 1
value | instruction_seed stringlengths 27 14.4k | _source stringclasses 1
value |
|---|---|---|---|---|---|---|---|---|
http://rosettacode.org/wiki/Stack_traces | Stack traces | Many programming languages allow for introspection of the current call stack environment. This can be for a variety of purposes such as enforcing security checks, debugging, or for getting access to the stack frame of callers.
Task
Print out (in a manner considered suitable for the platform) the current call stack.... | #Elixir | Elixir | defmodule Stack_traces do
def main do
{:ok, a} = outer
IO.inspect a
end
defp outer do
{:ok, a} = middle
{:ok, a}
end
defp middle do
{:ok, a} = inner
{:ok, a}
end
defp inner do
try do
throw(42)
catch 42 -> {:ok, :erlang.get_stacktrace}
end
end
end
Stack... | Give a code snippet in #Elixir
Many programming languages allow for introspection of the current call stack environment. This can be for a variety of purposes such as enforcing security checks, debugging, or for getting access to the stack frame of callers.
Task
Print out (in a manner considered suitable for the p... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows | Bulls and cows | Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the guess is the same as the random... | #Lua | Lua | function ShuffleArray(array)
for i=1,#array-1 do
local t = math.random(i, #array)
array[i], array[t] = array[t], array[i]
end
end
function GenerateNumber()
local digits = {1,2,3,4,5,6,7,8,9}
ShuffleArray(digits)
return digits[1] * 1000 +
digits[2] * 100 +
digits[3] ... | Give a code snippet in #Lua
Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the gu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catmull%E2%80%93Clark_subdivision_surface | Catmull–Clark subdivision surface | Implement the Catmull-Clark surface subdivision (description on Wikipedia), which is an algorithm that maps from a surface (described as a set of points and a set of polygons with vertices at those points) to another more refined surface. The resulting surface will always consist of a mesh of quadrilaterals.
The proce... | #Go | Go | package main
import (
"fmt"
"sort"
)
type (
Point [3]float64
Face []int
Edge struct {
pn1 int // point number 1
pn2 int // point number 2
fn1 int // face number 1
fn2 int // face number 2
cp Point // center point
}
PointEx struct {
... | Give a code snippet in #Go
Implement the Catmull-Clark surface subdivision (description on Wikipedia), which is an algorithm that maps from a surface (described as a set of points and a set of polygons with vertices at those points) to another more refined surface. The resulting surface will always consist of a mesh o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Call_a_foreign-language_function | Call a foreign-language function | Task
Show how a foreign language function can be called from the language.
As an example, consider calling functions defined in the C language. Create a string containing "Hello World!" of the string type typical to the language. Pass the string content to C's strdup. The content can be copied if necessary. Get the... | #Lisaac | Lisaac | Section Header
+ name := TEST_C_INTERFACE;
// this will be inserted in front of the program
- external := `#include <string.h>`;
Section Public
- main <- (
+ s : STRING_CONSTANT;
+ p : NATIVE_ARRAY[CHARACTER];
s := "Hello World!";
p := s.to_external;
// this will be inserted in-place
// use `expr`... | Give a code snippet in #Lisaac
Task
Show how a foreign language function can be called from the language.
As an example, consider calling functions defined in the C language. Create a string containing "Hello World!" of the string type typical to the language. Pass the string content to C's strdup. The content can... | christopher/rosetta-code | |
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... | #AppleScript | AppleScript | --------------------- CHURCH NUMERALS --------------------
-- churchZero :: (a -> a) -> a -> a
on churchZero(f, x)
x
end churchZero
-- churchSucc :: ((a -> a) -> a -> a) -> (a -> a) -> a -> a
on churchSucc(n)
script
on |λ|(f)
script
property mf : mReturn(f)
... | Give a code snippet in #AppleScript
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 appl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Legendre_prime_counting_function | Legendre prime counting function | The prime-counting function π(n) computes the number of primes not greater than n. Legendre was the first mathematician to create a formula to compute π(n) based on the inclusion/exclusion principle.
To calculate:
Define
φ(x, 0) = x
φ(x, a) = φ(x, a−1) − φ(⌊x/pa⌋, a−1), where pa is the ath prime number.
then
π(n) ... | #Wren | Wren | import "/math" for Int
var limit = 1e9.sqrt.floor
var primes = Int.primeSieve(limit)
var memoPhi = {}
var phi // recursive function
phi = Fn.new { |x, a|
if (a == 0) return x
var key = Int.cantorPair(x, a)
if (memoPhi.containsKey(key)) return memoPhi[key]
var pa = primes[a-1]
return memoPhi[key]... | Give a code snippet in #Wren
The prime-counting function π(n) computes the number of primes not greater than n. Legendre was the first mathematician to create a formula to compute π(n) based on the inclusion/exclusion principle.
To calculate:
Define
φ(x, 0) = x
φ(x, a) = φ(x, a−1) − φ(⌊x/pa⌋, a−1), where pa is the ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Return_multiple_values | Return multiple values | Task
Show how to return more than one value from a function.
| #ooRexx | ooRexx |
r = addsub(3, 4)
say r[1] r[2]
::routine addsub
use arg x, y
return .array~of(x + y, x - y)
| Give a code snippet in #ooRexx
Task
Show how to return more than one value from a function.
| christopher/rosetta-code | |
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
... | #Raku | Raku | .say for combinations(5,3); | Give a code snippet in #Raku
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Roots_of_a_function | Roots of a function | Task
Create a program that finds and outputs the roots of a given function, range and (if applicable) step width.
The program should identify whether the root is exact or approximate.
For this task, use: ƒ(x) = x3 - 3x2 + 2x
| #BBC_BASIC | BBC BASIC | function$ = "x^3-3*x^2+2*x"
rangemin = -1
rangemax = 3
stepsize = 0.001
accuracy = 1E-8
PROCroots(function$, rangemin, rangemax, stepsize, accuracy)
END
DEF PROCroots(func$, min, max, inc, eps)
LOCAL x, sign%, oldsign%
oldsign% = 0
FOR x = min TO max S... | Give a code snippet in #BBC_BASIC
Task
Create a program that finds and outputs the roots of a given function, range and (if applicable) step width.
The program should identify whether the root is exact or approximate.
For this task, use: ƒ(x) = x3 - 3x2 + 2x
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Merge_sort | Sorting algorithms/Merge sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #REXX | REXX | /*REXX pgm sorts a stemmed array (numbers and/or chars) using the merge─sort algorithm.*/
call init /*sinfully initialize the @ array. */
call show 'before sort' /*show the "before" array elements. */
say copies('▒', 75)... | Give a code snippet in #REXX
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sor... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #Eero | Eero | #import <Foundation/Foundation.h>
int main()
i := (int)'123' + 1
s := @(i).description
Log( '%@', s )
return 0 | Give a code snippet in #Eero
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Define_a_primitive_data_type | Define a primitive data type | Demonstrate how to define a type that behaves like an integer but has a lowest valid value of 1 and a highest valid value of 10. Include all bounds checking you need to write, or explain how the compiler or interpreter creates those bounds checks for you.
| #Swift | Swift | struct SmallInt {
var value: Int
init(value: Int) {
guard value >= 1 && value <= 10 else {
fatalError("SmallInts must be in the range [1, 10]")
}
self.value = value
}
static func +(_ lhs: SmallInt, _ rhs: SmallInt) -> SmallInt { SmallInt(value: lhs.value + rhs.value) }
static func -(_ ... | Give a code snippet in #Swift
Demonstrate how to define a type that behaves like an integer but has a lowest valid value of 1 and a highest valid value of 10. Include all bounds checking you need to write, or explain how the compiler or interpreter creates those bounds checks for you.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/XML/DOM_serialization | XML/DOM serialization | Create a simple DOM and having it serialize to:
<?xml version="1.0" ?>
<root>
<element>
Some text here
</element>
</root>
| #Pascal | Pascal | program CrearXML;
{$mode objfpc}{$H+}
uses
Classes, XMLWrite, DOM;
var
xdoc: TXMLDocument; // variable objeto documento XML
NodoRaiz, NodoPadre, NodoHijo: TDOMNode; // variables a los nodos
begin
//crear el documento
xdoc := TXMLDocument.create;
NodoRaiz ... | Give a code snippet in #Pascal
Create a simple DOM and having it serialize to:
<?xml version="1.0" ?>
<root>
<element>
Some text here
</element>
</root>
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer cou... | #JavaScript | JavaScript | function countSubstring(str, subStr) {
var matches = str.match(new RegExp(subStr, "g"));
return matches ? matches.length : 0;
} | Give a code snippet in #JavaScript
Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Associative_array/Creation | Associative array/Creation | Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element ins... | #8th | 8th |
{ "one" : 1, "two" : "bad" }
| Give a code snippet in #8th
Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, El... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Index_finite_lists_of_positive_integers | Index finite lists of positive integers | It is known that the set of finite lists of positive integers is countable.
This means that there exists a subset of natural integers which can be mapped to the set of finite lists of positive integers.
Task
Implement such a mapping:
write a function rank which assigns an integer to any finite, arbi... | #Java | Java | import java.math.BigInteger;
import static java.util.Arrays.stream;
import java.util.*;
import static java.util.stream.Collectors.*;
public class Test3 {
static BigInteger rank(int[] x) {
String s = stream(x).mapToObj(String::valueOf).collect(joining("F"));
return new BigInteger(s, 16);
}
... | Give a code snippet in #Java
It is known that the set of finite lists of positive integers is countable.
This means that there exists a subset of natural integers which can be mapped to the set of finite lists of positive integers.
Task
Implement such a mapping:
write a function rank which assigns ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic/Integer | Arithmetic/Integer |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #Bracmat | Bracmat | ( enter
= put$"Enter two integer numbers, separated by space:"
& get':(~/#?k_~/#?m|quit:?k)
| out
$ "You must enter two integer numbers! Enter \"quit\" if you don't know how to do that."
& !enter
)
& !enter
& !k:~quit
& out$("You entered" !k and !m ". Now look:")
& out$("Sum:" !k+!... | Give a code snippet in #Bracmat
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operation... | christopher/rosetta-code | |
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... | #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 ... | Give a code snippet in #Python
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 runt... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pernicious_numbers | Pernicious numbers | A pernicious number is a positive integer whose population count is a prime.
The population count is the number of ones in the binary representation of a non-negative integer.
Example
22 (which is 10110 in binary) has a population count of 3, which is prime, and therefore
22 is a pe... | #Nim | Nim | import strutils
proc count(s: string; sub: char): int =
var i = 0
while true:
i = s.find(sub, i)
if i < 0:
break
inc i
inc result
proc popcount(n: int): int = n.toBin(64).count('1')
const primes = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61}
var p: seq[int]
var ... | Give a code snippet in #Nim
A pernicious number is a positive integer whose population count is a prime.
The population count is the number of ones in the binary representation of a non-negative integer.
Example
22 (which is 10110 in binary) has a population count of 3, which is prime, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_to_100 | Sum to 100 | Task
Find solutions to the sum to one hundred puzzle.
Add (insert) the mathematical
operators + or - (plus
or minus) before any of the digits in the
decimal numeric string 123456789 such that the
resulting mathematical expression adds up to a
particular sum (in this iconic case, ... | #C.23 | C# | using System;
using System.Collections.Generic;
using System.Linq;
class Program
{
static void Main(string[] args)
{
// All unique expressions that have a plus sign in front of the 1; calculated in parallel
var expressionsPlus = Enumerable.Range(0, (int)Math.Pow(3, 8)).AsParallel().Select(i =>... | Give a code snippet in #C.23
Task
Find solutions to the sum to one hundred puzzle.
Add (insert) the mathematical
operators + or - (plus
or minus) before any of the digits in the
decimal numeric string 123456789 such that the
resulting mathematical expression adds up to a
particular ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #M2000_Interpreter | M2000 Interpreter |
Module checkit {
Declare random1 lib "advapi32.SystemFunction036" {long lpbuffer, long length}
Buffer Clear Alfa as long*2
Print Eval(Alfa,0)
Print Eval(Alfa,1)
call void random1(alfa(0), 8)
Print Eval(Alfa,0)
Print Eval(Alfa,1)
}
checkit
| Give a code snippet in #M2000_Interpreter
Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/URL_decoding | URL decoding | This task (the reverse of URL encoding and distinct from URL parser) is to provide a function
or mechanism to convert an URL-encoded string into its original unencoded form.
Test cases
The encoded string "http%3A%2F%2Ffoo%20bar%2F" should be reverted to the unencoded form "http://foo bar/".
Th... | #jq | jq | # Emit . and stop as soon as "condition" is true.
def until(condition; next):
def u: if condition then . else (next|u) end;
u;
def url_decode:
# The helper function converts the input string written in the given
# "base" to an integer
def to_i(base):
explode
| reverse
| map(if 65 <= . and . <= 9... | Give a code snippet in #jq
This task (the reverse of URL encoding and distinct from URL parser) is to provide a function
or mechanism to convert an URL-encoded string into its original unencoded form.
Test cases
The encoded string "http%3A%2F%2Ffoo%20bar%2F" should be reverted to the unencoded for... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Roman_numerals/Encode | Roman numerals/Encode | Task
Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero.
In Roman numeral... | #Peloton | Peloton | <@ DEFUDOLITLIT>_RO|__Transformer|<@ DEFKEYPAR>__NationalNumericID|2</@><@ LETRESCS%NNMPAR>...|1</@></@>
<@ ENU$$DLSTLITLIT>1990,2008,1,2,64,124,1666,10001|,|
<@ SAYELTLST>...</@> is <@ SAY_ROELTLSTLIT>...|RomanLowerUnicode</@> <@ SAY_ROELTLSTLIT>...|RomanUpperUnicode</@> <@ SAY_ROELTLSTLIT>...|RomanASCII</@>
</@> | Give a code snippet in #Peloton
Task
Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a v... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Two_bullet_roulette | Two bullet roulette | The following is supposedly a question given to mathematics graduates seeking jobs on Wall Street:
A revolver handgun has a revolving cylinder with six chambers for bullets.
It is loaded with the following procedure:
1. Check the first chamber to the right of the trigger for a bullet. If a bullet
is seen, the cyli... | #Factor | Factor | USING: accessors assocs circular formatting fry kernel literals
math random sequences ;
IN: rosetta-code.roulette
CONSTANT: cyl $[ { f f f f f f } <circular> ]
: cylinder ( -- seq ) cyl [ drop f ] map! ;
: load ( seq -- seq' )
0 over nth [ dup rotate-circular ] when
t 0 rot [ set-nth ] [ rotate-circular ]... | Give a code snippet in #Factor
The following is supposedly a question given to mathematics graduates seeking jobs on Wall Street:
A revolver handgun has a revolving cylinder with six chambers for bullets.
It is loaded with the following procedure:
1. Check the first chamber to the right of the trigger for a bulle... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
... | #Common_Lisp | Common Lisp | (let ((s (format () "~s" (expt 5 (expt 4 (expt 3 2))))))
(format t "~a...~a, length ~a" (subseq s 0 20)
(subseq s (- (length s) 20)) (length s))) | Give a code snippet in #Common_Lisp
Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pythagorean_triples | Pythagorean triples | A Pythagorean triple is defined as three positive integers
(
a
,
b
,
c
)
{\displaystyle (a,b,c)}
where
a
<
b
<
c
{\displaystyle a<b<c}
, and
a
2
+
b
2
=
c
2
.
{\displaystyle a^{2}+b^{2}=c^{2}.}
They are called primitive triples if
a
,
b
,
c
{\displaystyle a,b,c}
are co-prime,... | #Erlang | Erlang | %%
%% Pythagorian triples in Erlang, J.W. Luiten
%%
-module(triples).
-export([main/1]).
%% Transformations t1, t2 and t3 to generate new triples
t1(A, B, C) ->
{A-2*B+2*C, 2*A-B+2*C, 2*A-2*B+3*C}.
t2(A, B, C) ->
{A+2*B+2*C, 2*A+B+2*C, 2*A+2*B+3*C}.
t3(A, B, C) ->
{2*B+2*C-A, B+2*C-2*A, 2*B+3*C-2*A}.
%% G... | Give a code snippet in #Erlang
A Pythagorean triple is defined as three positive integers
(
a
,
b
,
c
)
{\displaystyle (a,b,c)}
where
a
<
b
<
c
{\displaystyle a<b<c}
, and
a
2
+
b
2
=
c
2
.
{\displaystyle a^{2}+b^{2}=c^{2}.}
They are called primitive triples if
a
,
b
,
c
{\dis... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rename_a_file | Rename a file | Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the rights to do so.
(In unix-type s... | #Standard_ML | Standard ML | OS.FileSys.rename {old = "input.txt", new = "output.txt"};
OS.FileSys.rename {old = "docs", new = "mydocs"};
OS.FileSys.rename {old = "/input.txt", new = "/output.txt"};
OS.FileSys.rename {old = "/docs", new = "/mydocs"}; | Give a code snippet in #Standard_ML
Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has ... | christopher/rosetta-code | |
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, ... | #Visual_Basic_.NET | Visual Basic .NET | Module Module1
Structure MonDay
Dim month As String
Dim day As Integer
Sub New(m As String, d As Integer)
month = m
day = d
End Sub
Public Overrides Function ToString() As String
Return String.Format("({0}, {1})", month, day)
... | Give a code snippet in #Visual_Basic_.NET
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Statistics/Basic | Statistics/Basic | Statistics is all about large groups of numbers.
When talking about a set of sampled data, most frequently used is their mean value and standard deviation (stddev).
If you have set of data
x
i
{\displaystyle x_{i}}
where
i
=
1
,
2
,
…
,
n
{\displaystyle i=1,2,\ldots ,n\,\!}
, the mean is
x
¯... | #Ada | Ada | with Ada.Text_IO, Ada.Command_Line, Ada.Numerics.Float_Random,
Ada.Numerics.Generic_Elementary_Functions;
procedure Basic_Stat is
package FRG renames Ada.Numerics.Float_Random;
package TIO renames Ada.Text_IO;
type Counter is range 0 .. 2**31-1;
type Result_Array is array(Natural range <>) of Counte... | Give a code snippet in #Ada
Statistics is all about large groups of numbers.
When talking about a set of sampled data, most frequently used is their mean value and standard deviation (stddev).
If you have set of data
x
i
{\displaystyle x_{i}}
where
i
=
1
,
2
,
…
,
n
{\displaystyle i=1,2,\ldots ,n\,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Queue/Definition | Queue/Definition |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operation... | #Fantom | Fantom |
class Queue
{
List queue := [,]
public Void push (Obj obj)
{
queue.add (obj) // add to right of list
}
public Obj pop ()
{
if (queue.isEmpty)
throw (Err("queue is empty"))
else
{
return queue.removeAt(0) // removes left-most item
}
}
public Bool isEmpty ()
{
... | Give a code snippet in #Fantom
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_word/fractal | Fibonacci word/fractal |
The Fibonacci word may be represented as a fractal as described here:
(Clicking on the above website (hal.archives-ouvertes.fr) will leave a cookie.)
For F_wordm start with F_wordCharn=1
Draw a segment forward
If current F_wordChar is 0
Turn left if n is even
Turn right if n is odd
next n and iterate until e... | #Rust | Rust | // [dependencies]
// svg = "0.8.0"
use svg::node::element::path::Data;
use svg::node::element::Path;
fn fibonacci_word(n: usize) -> Vec<u8> {
let mut f0 = vec![1];
let mut f1 = vec![0];
if n == 0 {
return f0;
} else if n == 1 {
return f1;
}
let mut i = 2;
loop {
l... | Give a code snippet in #Rust
The Fibonacci word may be represented as a fractal as described here:
(Clicking on the above website (hal.archives-ouvertes.fr) will leave a cookie.)
For F_wordm start with F_wordCharn=1
Draw a segment forward
If current F_wordChar is 0
Turn left if n is even
Turn right if n is ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ackermann_function | Ackermann function | The Ackermann function is a classic example of a recursive function, notable especially because it is not a primitive recursive function. It grows very quickly in value, as does the size of its call tree.
The Ackermann function is usually defined as follows:
A
(
m
,
n
)
=
{
n
+
1
if
m
=
0
A
(
m
... | #ooRexx | ooRexx |
loop m = 0 to 3
loop n = 0 to 6
say "Ackermann("m", "n") =" ackermann(m, n)
end
end
::routine ackermann
use strict arg m, n
-- give us some precision room
numeric digits 10000
if m = 0 then return n + 1
else if n = 0 then return ackermann(m - 1, 1)
else return ackermann(m - 1, ackermann(... | Give a code snippet in #ooRexx
The Ackermann function is a classic example of a recursive function, notable especially because it is not a primitive recursive function. It grows very quickly in value, as does the size of its call tree.
The Ackermann function is usually defined as follows:
A
(
m
,
n
)
=
{
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Runtime_evaluation | Runtime evaluation | Task
Demonstrate a language's ability for programs to execute code written in the language provided at runtime.
Show what kind of program fragments are permitted (e.g. expressions vs. statements), and how to get values in and out (e.g. environments, arguments, return values), if applicable what lexical/static environ... | #BASIC | BASIC | 100 DEF PROC graph f$
110 LOCAL x,y
120 PLOT 0,90
130 FOR x = -2 TO 2 STEP 0.02
140 LET y = VAL(f$)
150 DRAW TO x*50+100, y*50+90
160 NEXT x
170 END PROC
| Give a code snippet in #BASIC
Task
Demonstrate a language's ability for programs to execute code written in the language provided at runtime.
Show what kind of program fragments are permitted (e.g. expressions vs. statements), and how to get values in and out (e.g. environments, arguments, return values), if applica... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Jump_anywhere | Jump anywhere | Imperative programs
conditional structures
loops
local jumps
This task is to demonstrate a local jump and a global jump and the various other types of jumps that the language supports.
For the purpose of this task, the jumps need not be used for a single purpose and you have the freedom to use these jumps for different... | #VBScript | VBScript | 1010 ?="@1010: Where to goto? ";
1020 #=?
1030 ?="@1030"
1040 #=1010
1050 ?="@1050"
1060 #=1010
2000 ?="@2000"
2010 ?="Exiting..." | Give a code snippet in #VBScript
Imperative programs
conditional structures
loops
local jumps
This task is to demonstrate a local jump and a global jump and the various other types of jumps that the language supports.
For the purpose of this task, the jumps need not be used for a single purpose and you have the freedo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/The_Name_Game | The Name Game | Write a program that accepts a name as input and outputs the lyrics to the Shirley Ellis song "The Name Game".
The regular verse
Unless your name begins with a vowel (A, E, I, O, U), 'B', 'F' or 'M' you don't have to care about special rules.
The verse for the name 'Gary' would be like this:
Gary, Gary, bo-bary... | #Kotlin | Kotlin | // version 1.2.31
fun printVerse(name: String) {
val x = name.toLowerCase().capitalize()
val y = if (x[0] in "AEIOU") x.toLowerCase() else x.substring(1)
var b = "b$y"
var f = "f$y"
var m = "m$y"
when (x[0]) {
'B' -> b = "$y"
'F' -> f = "$y"
'M' -> m = "$y"
e... | Give a code snippet in #Kotlin
Write a program that accepts a name as input and outputs the lyrics to the Shirley Ellis song "The Name Game".
The regular verse
Unless your name begins with a vowel (A, E, I, O, U), 'B', 'F' or 'M' you don't have to care about special rules.
The verse for the name 'Gary' would be li... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows | Bulls and cows | Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the guess is the same as the random... | #Crystal | Crystal | size = 4
secret = ('1'..'9').to_a.sample(size)
guess = [] of Char
i = 0
loop do
i += 1
loop do
print "Guess #{i}: "
guess = gets.not_nil!.chomp.chars
exit if guess.empty?
break if guess.size == size &&
guess.all? { |x| ('1'..'9').includes? x } &&
guess.uniq.size == size... | Give a code snippet in #Crystal
Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Window_creation | Window creation | Display a GUI window. The window need not have any contents, but should respond to requests to be closed.
| #Ada | Ada | with Gtk.Window; use Gtk.Window;
with Gtk.Widget; use Gtk.Widget;
with Gtk.Handlers;
with Gtk.Main;
procedure Windowed_Application is
Window : Gtk_Window;
package Handlers is new Gtk.Handlers.Callback (Gtk_Widget_Record);
package Return_Handlers is
new Gtk.Handlers.Return_Callback (Gtk_Widget_Rec... | Give a code snippet in #Ada
Display a GUI window. The window need not have any contents, but should respond to requests to be closed.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Call_an_object_method | Call an object method | In object-oriented programming a method is a function associated with a particular class or object. In most forms of object oriented implementations methods can be static, associated with the class itself; or instance, associated with an instance of a class.
Show how to call a static or class method, and an instance m... | #PowerShell | PowerShell | $Date = Get-Date
$Date.AddDays( 1 )
[System.Math]::Sqrt( 2 ) | Give a code snippet in #PowerShell
In object-oriented programming a method is a function associated with a particular class or object. In most forms of object oriented implementations methods can be static, associated with the class itself; or instance, associated with an instance of a class.
Show how to call a stati... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Cursor_movement | Terminal control/Cursor movement | Task
Demonstrate how to achieve movement of the terminal cursor:
how to move the cursor one position to the left
how to move the cursor one position to the right
how to move the cursor up one line (without affecting its horizontal position)
how to move the cursor down one line (without affecting its horizontal po... | #Action.21 | Action! | PROC Wait(BYTE frames)
BYTE RTCLOK=$14
frames==+RTCLOK
WHILE frames#RTCLOK DO OD
RETURN
PROC Main()
BYTE
d=[50],
CH=$02FC, ;Internal hardware value for last key pressed
ROWCRS=$0054 ;Current cursor row
CARD COLCRS=$0055 ;Current cursor column
Graphics(0)
Position(2,2)
Print("Press any ke... | Give a code snippet in #Action.21
Task
Demonstrate how to achieve movement of the terminal cursor:
how to move the cursor one position to the left
how to move the cursor one position to the right
how to move the cursor up one line (without affecting its horizontal position)
how to move the cursor down one line (... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sailors,_coconuts_and_a_monkey_problem | Sailors, coconuts and a monkey problem | Five sailors are shipwrecked on an island and collect a large pile of coconuts during the day.
That night the first sailor wakes up and decides to take his first share early so tries to divide the pile of coconuts equally into five piles but finds that there is one coconut left over, so he tosses it to a monkey and th... | #Racket | Racket | #lang racket
(define (wake-and-split nuts sailors depth wakes)
(define-values (portion remainder) (quotient/remainder nuts sailors))
(define monkey (if (zero? depth) 0 1))
(define new-wakes (cons (list nuts portion remainder) wakes))
(and (positive? portion)
(= remainder monkey)
(if (zero? depth... | Give a code snippet in #Racket
Five sailors are shipwrecked on an island and collect a large pile of coconuts during the day.
That night the first sailor wakes up and decides to take his first share early so tries to divide the pile of coconuts equally into five piles but finds that there is one coconut left over, so... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Tokenize_a_string_with_escaping | Tokenize a string with escaping | Task[edit]
Write a function or program that can split a string at each non-escaped occurrence of a separator character.
It should accept three input parameters:
The string
The separator character
The escape character
It should output a list of strings.
Details
Rules for splitting:
The fields that were s... | #Haskell | Haskell | splitEsc :: (Foldable t1, Eq t) => t -> t -> t1 t -> [[t]]
splitEsc sep esc = reverse . map reverse . snd . foldl process (0, [[]])
where process (st, r:rs) ch
| st == 0 && ch == esc = (1, r:rs)
| st == 0 && ch == sep = (0, []:r:rs)
| st == 1 && sep == ... | Give a code snippet in #Haskell
Task[edit]
Write a function or program that can split a string at each non-escaped occurrence of a separator character.
It should accept three input parameters:
The string
The separator character
The escape character
It should output a list of strings.
Details
Rules for sp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Metaprogramming | Metaprogramming | Name and briefly demonstrate any support your language has for metaprogramming. Your demonstration may take the form of cross-references to other tasks on Rosetta Code. When possible, provide links to relevant documentation.
For the purposes of this task, "support for metaprogramming" means any way the user can effect... | #Python | Python |
from macropy.core.macros import *
from macropy.core.quotes import macros, q, ast, u
macros = Macros()
@macros.expr
def expand(tree, **kw):
addition = 10
return q[lambda x: x * ast[tree] + u[addition]]
| Give a code snippet in #Python
Name and briefly demonstrate any support your language has for metaprogramming. Your demonstration may take the form of cross-references to other tasks on Rosetta Code. When possible, provide links to relevant documentation.
For the purposes of this task, "support for metaprogramming" m... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Nim_game | Nim game | Nim game
You are encouraged to solve this task according to the task description, using any language you may know.
Nim is a simple game where the second player ─── if they know the trick ─── will always win.
The game has only 3 rules:
start with 12 tokens
each player takes 1, 2, or 3 tokens in tur... | #Swift | Swift | var tokens = 12
while tokens != 0 {
print("Tokens remaining: \(tokens)\nPlease enter a number between 1 and 3: ", terminator: "")
guard let input = readLine(), let n = Int(input), n >= 1 && n <= 3 else {
fatalError("Invalid input")
}
tokens -= n
if tokens == 0 {
print("You win!")
break
... | Give a code snippet in #Swift
Nim game
You are encouraged to solve this task according to the task description, using any language you may know.
Nim is a simple game where the second player ─── if they know the trick ─── will always win.
The game has only 3 rules:
start with 12 tokens
each player takes ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Universal_Turing_machine | Universal Turing machine | One of the foundational mathematical constructs behind computer science
is the universal Turing Machine.
(Alan Turing introduced the idea of such a machine in 1936–1937.)
Indeed one way to definitively prove that a language
is turing-complete
is to implement a universal Turing machine in it.
Task
Simulate such ... | #Rust | Rust | use std::collections::VecDeque;
use std::fmt::{Display, Formatter, Result};
fn main() {
println!("Simple incrementer");
let rules_si = vec!(
Rule::new("q0", '1', '1', Direction::Right, "q0"),
Rule::new("q0", 'B', '1', Direction::Stay, "qf")
);
let states_si = vec!("q0", "qf");
let ... | Give a code snippet in #Rust
One of the foundational mathematical constructs behind computer science
is the universal Turing Machine.
(Alan Turing introduced the idea of such a machine in 1936–1937.)
Indeed one way to definitively prove that a language
is turing-complete
is to implement a universal Turing machine ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Window_management | Window management | Treat windows or at least window identities as first class objects.
Store window identities in variables, compare them for equality.
Provide examples of performing some of the following:
hide,
show,
close,
minimize,
maximize,
move, and
resize a window.
The window of interest may or may not have b... | #HicEst | HicEst | CHARACTER title="Rosetta Window_management"
REAL :: w=-333, h=25, x=1, y=0.5 ! pixels < 0, relative window size 0...1, script character size > 1
WINDOW(WINdowhandle=wh, Width=w, Height=h, X=x, Y=y, TItle=title) ! create, on return size/pos VARIABLES are set to script char
WINDOW(WIN=wh, MINimize) ! minimize
... | Give a code snippet in #HicEst
Treat windows or at least window identities as first class objects.
Store window identities in variables, compare them for equality.
Provide examples of performing some of the following:
hide,
show,
close,
minimize,
maximize,
move, and
resize a window.
The window o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Extreme_floating_point_values | Extreme floating point values | The IEEE floating point specification defines certain 'extreme' floating point values such as minus zero, -0.0, a value distinct from plus zero; not a number, NaN; and plus and minus infinity.
The task is to use expressions involving other 'normal' floating point values in your language to calculate these, (and maybe ... | #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | Column@{ReleaseHold[
Function[expression,
Row@{HoldForm@InputForm@expression, " = ", Quiet@expression},
HoldAll] /@
Hold[1./0., 0./0., Limit[-Log[x], x -> 0], Limit[Log[x], x -> 0],
Infinity + 1, Infinity + Infinity, 2 Infinity,
Infinity - Infinity, 0 Infinity, ComplexInfinity + 1,
... | Give a code snippet in #Mathematica_.2F_Wolfram_Language
The IEEE floating point specification defines certain 'extreme' floating point values such as minus zero, -0.0, a value distinct from plus zero; not a number, NaN; and plus and minus infinity.
The task is to use expressions involving other 'normal' floating poi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Lychrel_numbers | Lychrel numbers | Take an integer n, greater than zero.
Form the next n of its series by reversing the digits of the current n and adding the result to the current n.
Stop when n becomes palindromic - i.e. the digits of n in reverse order == n.
The above recurrence relation when applied to most starting numbers n = 1, 2, ... ... | #ALGOL_68 | ALGOL 68 | PR read "aArray.a68" PR
# number of additions to attempt before deciding the number is Lychrel #
INT max additions = 500;
# buffer to hold number during testing #
# addition of two equal sized numbers can produce a number of at most #
# one additional digit, so for 500 additions of ... | Give a code snippet in #ALGOL_68
Take an integer n, greater than zero.
Form the next n of its series by reversing the digits of the current n and adding the result to the current n.
Stop when n becomes palindromic - i.e. the digits of n in reverse order == n.
The above recurrence relation when applied to mo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ethiopian_multiplication | Ethiopian multiplication | Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ... | #Arturo | Arturo | halve: function [x]-> shr x 1
double: function [x]-> shl x 1
; even? already exists
ethiopian: function [x y][
prod: 0
while [x > 0][
unless even? x [prod: prod + y]
x: halve x
y: double y
]
return prod
]
print ethiopian 17 34
print ethiopian 2 3 | Give a code snippet in #Arturo
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Downward_for | Loops/Downward for | Task
Write a for loop which writes a countdown from 10 to 0.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within loop body... | #Clipper | Clipper | FOR i := 10 TO 0 STEP -1
? i
NEXT | Give a code snippet in #Clipper
Task
Write a for loop which writes a countdown from 10 to 0.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Incr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mutual_recursion | Mutual recursion | Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
)
=
n
−
M
(
F
(
n
−
1
)
)
,
... | #zkl | zkl | fcn f(n){ if(n==0)return(1); n-m(f(n-1,m),f) }
fcn m(n){ if(n==0)return(0); n-f(m(n-1,f),m) }
[0..19].apply(f).println(); // or foreach n in ([0..19]){ print(f(n)," ") }
[0..19].apply(m).println(); // or foreach n in ([0..19]){ print(m(n)," ") } | Give a code snippet in #zkl
Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
)
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Peano_curve | Peano curve |
Task
Produce a graphical or ASCII-art representation of a Peano curve of at least order 3.
| #Processing | Processing |
//Abhishek Ghosh, 28th June 2022
void Peano(int x, int y, int lg, int i1, int i2) {
if (lg == 1) {
ellipse(x,y,1,1);
return;
}
lg = lg/3;
Peano(x+(2*i1*lg), y+(2*i1*lg), lg, i1, i2);
Peano(x+((i1-i2+1)*lg), y+((i1+i2)*lg), lg, i1, 1-i2);
Peano(x+lg, y+lg, lg, i1, 1-i2);
Peano(x+((i1+i2)*lg... | Give a code snippet in #Processing
Task
Produce a graphical or ASCII-art representation of a Peano curve of at least order 3.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Knapsack_problem/Bounded | Knapsack problem/Bounded | A tourist wants to make a good trip at the weekend with his friends.
They will go to the mountains to see the wonders of nature. So he needs some items during the trip. Food, clothing, etc. He has a good knapsack for carrying the things, but he knows that he can carry only 4 kg weight in his knapsack, because th... | #R | R | library(tidyverse)
library(rvest)
task_html= read_html("http://rosettacode.org/wiki/Knapsack_problem/Bounded")
task_table= html_nodes(html, "table")[[1]] %>%
html_table(table, header= T, trim= T) %>%
set_names(c("items", "weight", "value", "pieces")) %>%
filter(items != "knapsack") %>%
mutate(weight= as.numer... | Give a code snippet in #R
A tourist wants to make a good trip at the weekend with his friends.
They will go to the mountains to see the wonders of nature. So he needs some items during the trip. Food, clothing, etc. He has a good knapsack for carrying the things, but he knows that he can carry only 4 kg weight ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stirling_numbers_of_the_second_kind | Stirling numbers of the second kind | Stirling numbers of the second kind, or Stirling partition numbers, are the
number of ways to partition a set of n objects into k non-empty subsets. They are
closely related to Bell numbers, and may be derived from them.
Stirling numbers of the second kind obey the recurrence relation:
S2(n, 0) and S2(0, k) = 0 ... | #Factor | Factor | USING: combinators.short-circuit formatting io kernel math
math.extras prettyprint sequences ;
RENAME: stirling math.extras => (stirling)
IN: rosetta-code.stirling-second
! Tweak Factor's in-built stirling function for k=0
: stirling ( n k -- m )
2dup { [ = not ] [ nip zero? ] } 2&&
[ 2drop 0 ] [ (stirling) ]... | Give a code snippet in #Factor
Stirling numbers of the second kind, or Stirling partition numbers, are the
number of ways to partition a set of n objects into k non-empty subsets. They are
closely related to Bell numbers, and may be derived from them.
Stirling numbers of the second kind obey the recurrence relation... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Elixir | Elixir | path = hd(System.argv)
IO.puts File.dir?(path) and Enum.empty?( File.ls!(path) ) | Give a code snippet in #Elixir
Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an e... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Magic_squares_of_odd_order | Magic squares of odd order | A magic square is an NxN square matrix whose numbers (usually integers) consist of consecutive numbers arranged so that the sum of each row and column, and both long (main) diagonals are equal to the same sum (which is called the magic number or magic constant).
The numbers are usually (but not always) t... | #Pascal | Pascal | PROGRAM magic;
(* Magic squares of odd order *)
CONST
n=9;
VAR
i,j :INTEGER;
BEGIN (*magic*)
WRITELN('The square order is: ',n);
FOR i:=1 TO n DO
BEGIN
FOR j:=1 TO n DO
WRITE((i*2-j+n-1) MOD n*n + (i*2+j-2) MOD n+1:5);
WRITELN
END;
WRITELN('The magic number is: ',n*(n*n+1) DIV 2)
END (*magic... | Give a code snippet in #Pascal
A magic square is an NxN square matrix whose numbers (usually integers) consist of consecutive numbers arranged so that the sum of each row and column, and both long (main) diagonals are equal to the same sum (which is called the magic number or magic constant).
The number... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Write_entire_file | Write entire file | Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| #Ada | Ada | with Ada.Text_IO; use Ada.Text_IO;
procedure Write_Whole_File is
File_Name : constant String := "the_file.txt";
F : File_Type;
begin
begin
Open (F, Mode => Out_File, Name => File_Name);
exception
when Name_Error => Create (F, Mode => Out_File, Name => File_Name);
end;
Put (F, "(Over... | Give a code snippet in #Ada
Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Deepcopy | Deepcopy | Task
Demonstrate how to copy data structures containing complex heterogeneous and cyclic semantics.
This is often referred to as deep copying, and is normally required where structures are mutable and to ensure that independent copies can be manipulated without side-effects.
If this facility is not built into the la... | #C.2B.2B | C++ |
#include <array>
#include <iostream>
#include <list>
#include <map>
#include <vector>
int main()
{
// make a nested structure to copy - a map of arrays containing vectors of strings
auto myNumbers = std::vector<std::string>{"one", "two", "three", "four"};
auto myColors = std::vector<std::string>{"red", ... | Give a code snippet in #C.2B.2B
Task
Demonstrate how to copy data structures containing complex heterogeneous and cyclic semantics.
This is often referred to as deep copying, and is normally required where structures are mutable and to ensure that independent copies can be manipulated without side-effects.
If this ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/System_time | System time | Task
Output the system time (any units will do as long as they are noted) either by a system command or one built into the language.
The system time can be used for debugging, network information, random number seeds, or something as simple as program performance.
Related task
Date format
See also
Retr... | #AppleScript | AppleScript | display dialog ((current date) as text) | Give a code snippet in #AppleScript
Task
Output the system time (any units will do as long as they are noted) either by a system command or one built into the language.
The system time can be used for debugging, network information, random number seeds, or something as simple as program performance.
Related tas... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Mode | Averages/Mode | Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriat... | #Racket | Racket | #lang racket
(define (mode seq)
(define frequencies (make-hash))
(for ([s seq])
(hash-update! frequencies
s
(lambda (freq) (add1 freq))
0))
(for/fold ([ms null]
[freq 0])
([(k v) (in-hash frequencies)])
(cond [(> v freq)
... | Give a code snippet in #Racket
Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if p... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_if_a_point_is_within_a_triangle | Find if a point is within a triangle | Find if a point is within a triangle.
Task
Assume points are on a plane defined by (x, y) real number coordinates.
Given a point P(x, y) and a triangle formed by points A, B, and C, determine if P is within triangle ABC.
You may use any algorithm.
Bonus: explain why the algorithm you chose works.
Re... | #REXX | REXX | /*REXX program determines if a specified point is within a specified triangle. */
parse arg p a b c . /*obtain optional arguments from the CL*/
if p=='' | p=="," then p= '(0,0)' /*Not specified? Then use the default.*/
if a=='' | a=="," then a= '(1.5,2.4)' ... | Give a code snippet in #REXX
Find if a point is within a triangle.
Task
Assume points are on a plane defined by (x, y) real number coordinates.
Given a point P(x, y) and a triangle formed by points A, B, and C, determine if P is within triangle ABC.
You may use any algorithm.
Bonus: explain why the a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mutual_recursion | Mutual recursion | Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
)
=
n
−
M
(
F
(
n
−
1
)
)
,
... | #Sidef | Sidef | func F(){}
func M(){}
F = func(n) { n > 0 ? (n - M(F(n-1))) : 1 }
M = func(n) { n > 0 ? (n - F(M(n-1))) : 0 }
[F, M].each { |seq|
{|i| seq.call(i)}.map(^20).join(' ').say
} | Give a code snippet in #Sidef
Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Optional_parameters | Optional parameters | Task
Define a function/method/subroutine which sorts a sequence ("table") of sequences ("rows") of strings ("cells"), by one of the strings. Besides the input to be sorted, it shall have the following optional parameters:
ordering
A function specifying the ordering of strings; lexicographic by default.
column
... | #Clojure | Clojure | (defn sort [table & {:keys [ordering column reverse?]
:or {ordering :lex, column 1}}]
(println table ordering column reverse?))
(sort [1 8 3] :reverse? true)
[1 8 3] :lex 1 true | Give a code snippet in #Clojure
Task
Define a function/method/subroutine which sorts a sequence ("table") of sequences ("rows") of strings ("cells"), by one of the strings. Besides the input to be sorted, it shall have the following optional parameters:
ordering
A function specifying the ordering of strings; l... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows | Bulls and cows | Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the guess is the same as the random... | #AutoHotkey | AutoHotkey | length:=4, Code:="" ; settings
While StrLen(Code) < length {
Random, num, 1, 9
If !InStr(Code, num)
Code .= num
}
Gui, Add, Text, w83 vInfo, I'm thinking of a %length%-digit number with no duplicate digits.
Gui, Add, Edit, wp vGuess, Enter a guess...
Gui, Add, Button, wp Default vDefault, Submit
Gui, Add, Edit, y... | Give a code snippet in #AutoHotkey
Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if... | christopher/rosetta-code | |
http://rosettacode.org/wiki/100_prisoners | 100 prisoners |
The Problem
100 prisoners are individually numbered 1 to 100
A room having a cupboard of 100 opaque drawers numbered 1 to 100, that cannot be seen from outside.
Cards numbered 1 to 100 are placed randomly, one to a drawer, and the drawers all closed; at the start.
Prisoners start outside the room
They can decid... | #Visual_Basic_.NET | Visual Basic .NET | Module Module1
Function PlayOptimal() As Boolean
Dim secrets = Enumerable.Range(0, 100).OrderBy(Function(a) Guid.NewGuid).ToList
For p = 1 To 100
Dim success = False
Dim choice = p - 1
For i = 1 To 50
If secrets(choice) = p - 1 Then
... | Give a code snippet in #Visual_Basic_.NET
The Problem
100 prisoners are individually numbered 1 to 100
A room having a cupboard of 100 opaque drawers numbered 1 to 100, that cannot be seen from outside.
Cards numbered 1 to 100 are placed randomly, one to a drawer, and the drawers all closed; at the start.
Priso... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Comb_sort | Sorting algorithms/Comb sort | Sorting algorithms/Comb sort
You are encouraged to solve this task according to the task description, using any language you may know.
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algor... | #PHP | PHP | function combSort($arr){
$gap = count($arr);
$swap = true;
while ($gap > 1 || $swap){
if($gap > 1) $gap /= 1.25;
$swap = false;
$i = 0;
while($i+$gap < count($arr)){
if($arr[$i] > $arr[$i+$gap]){
list($arr[$i], $arr[$i+$gap]) = array($arr[$i+$gap],$arr[$i]);
$swap = true;
}
$i++;
... | Give a code snippet in #PHP
Sorting algorithms/Comb sort
You are encouraged to solve this task according to the task description, using any language you may know.
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sor... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Case-sensitivity_of_identifiers | Case-sensitivity of identifiers | Three dogs (Are there three dogs or one dog?) is a code snippet used to illustrate the lettercase sensitivity of the programming language. For a case-sensitive language, the identifiers dog, Dog and DOG are all different and we should get the output:
The three dogs are named Benjamin, Samba and Bernie.
For a language... | #XLISP | XLISP | (SETQ DOG 'BENJAMIN)
(SETQ Dog 'SAMBA)
(SETQ dog 'BERNIE)
(DISPLAY `(THERE IS JUST ONE DOG NAMED ,DOG)) | Give a code snippet in #XLISP
Three dogs (Are there three dogs or one dog?) is a code snippet used to illustrate the lettercase sensitivity of the programming language. For a case-sensitive language, the identifiers dog, Dog and DOG are all different and we should get the output:
The three dogs are named Benjamin, Sa... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Shortest_common_supersequence | Shortest common supersequence | The shortest common supersequence is a problem closely related to the longest common subsequence, which you can use as an external function for this task.
Task
Given two strings
u
{\displaystyle u}
and
v
{\displaystyle v}
, find the shortest possible sequence
s
{\displaystyle s}
, whic... | #REXX | REXX | /*REXX program finds the Shortest common supersequence (SCS) of two character strings.*/
parse arg u v . /*obtain optional arguments from the CL*/
if u=='' | u=="," then u= 'abcbdab' /*Not specified? Then use the default.*/
if v=='' | v=="," then v= 'bdcaba' ... | Give a code snippet in #REXX
The shortest common supersequence is a problem closely related to the longest common subsequence, which you can use as an external function for this task.
Task
Given two strings
u
{\displaystyle u}
and
v
{\displaystyle v}
, find the shortest possible sequence
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/ABC_problem | ABC problem | ABC problem
You are encouraged to solve this task according to the task description, using any language you may know.
You are given a collection of ABC blocks (maybe like the ones you had when you were a kid).
There are twenty blocks with two letters on each block.
A complete alphabet is guaranteed amongst all sid... | #AppleScript | AppleScript | set blocks to {"bo", "xk", "dq", "cp", "na", "gt", "re", "tg", "qd", "fs", ¬
"jw", "hu", "vi", "an", "ob", "er", "fs", "ly", "pc", "zm"}
canMakeWordWithBlocks("a", blocks)
canMakeWordWithBlocks("bark", blocks)
canMakeWordWithBlocks("book", blocks)
canMakeWordWithBlocks("treat", blocks)
canMakeWordWithBlocks("comm... | Give a code snippet in #AppleScript
ABC problem
You are encouraged to solve this task according to the task description, using any language you may know.
You are given a collection of ABC blocks (maybe like the ones you had when you were a kid).
There are twenty blocks with two letters on each block.
A complete a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #Visual_Basic | Visual Basic | Dim s As String
' Assign empty string:
s = ""
' or
s = String.Empty
' Check for empty string only (false if s is null):
If s IsNot Nothing AndAlso s.Length = 0 Then
End If
' Check for null or empty (more idiomatic in .NET):
If String.IsNullOrEmpty(s) Then
End If | Give a code snippet in #Visual_Basic
Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/First-class_functions | First-class functions | A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as retu... | #AppleScript | AppleScript | -- Compose two functions, where each function is
-- a script object with a call(x) handler.
on compose(f, g)
script
on call(x)
f's call(g's call(x))
end call
end script
end compose
script increment
on call(n)
n + 1
end call
end script
script decrement
on call(... | Give a code snippet in #AppleScript
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/SHA-1 | SHA-1 | SHA-1 or SHA1 is a one-way hash function;
it computes a 160-bit message digest.
SHA-1 often appears in security protocols; for example,
many HTTPS websites use RSA with SHA-1 to secure their connections.
BitTorrent uses SHA-1 to verify downloads.
Git and Mercurial use SHA-1 digests to identify commits.
A US government... | #Haskell | Haskell | module Digestor
where
import Data.Digest.Pure.SHA
import qualified Data.ByteString.Lazy as B
convertString :: String -> B.ByteString
convertString phrase = B.pack $ map ( fromIntegral . fromEnum ) phrase
convertToSHA1 :: String -> String
convertToSHA1 word = showDigest $ sha1 $ convertString word
main = do
... | Give a code snippet in #Haskell
SHA-1 or SHA1 is a one-way hash function;
it computes a 160-bit message digest.
SHA-1 often appears in security protocols; for example,
many HTTPS websites use RSA with SHA-1 to secure their connections.
BitTorrent uses SHA-1 to verify downloads.
Git and Mercurial use SHA-1 digests to i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multiple_distinct_objects | Multiple distinct objects | Create a sequence (array, list, whatever) consisting of n distinct, initialized items of the same type. n should be determined at runtime.
By distinct we mean that if they are mutable, changes to one do not affect all others; if there is an appropriate equality operator they are considered unequal; etc. The code need ... | #Rust | Rust | use std::rc::Rc;
use std::cell::RefCell;
fn main() {
let size = 3;
// Clone the given element to fill out the vector.
let mut v: Vec<String> = vec![String::new(); size];
v[0].push('a');
println!("{:?}", v);
// Run a given closure to create each element.
let mut v: Vec<String> = (0..siz... | Give a code snippet in #Rust
Create a sequence (array, list, whatever) consisting of n distinct, initialized items of the same type. n should be determined at runtime.
By distinct we mean that if they are mutable, changes to one do not affect all others; if there is an appropriate equality operator they are considere... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Handle_a_signal | Handle a signal | Most operating systems provide interrupt facilities, sometimes called signals either generated by the user or as a result of program failure or reaching a limit like file space.
Unhandled signals generally terminate a program in a disorderly manner.
Signal handlers are created so that the program behaves in a well-defi... | #Erlang | Erlang | #! /usr/bin/env escript
main([]) ->
erlang:unregister(erl_signal_server),
erlang:register(erl_signal_server, self()),
Start = seconds(),
os:set_signal(sigquit, handle),
Pid = spawn(fun() -> output_loop(1) end),
receive
{notify, sigquit} ->
erlang:exit(Pid, normal),
... | Give a code snippet in #Erlang
Most operating systems provide interrupt facilities, sometimes called signals either generated by the user or as a result of program failure or reaching a limit like file space.
Unhandled signals generally terminate a program in a disorderly manner.
Signal handlers are created so that th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Break | Loops/Break | Task
Show a loop which prints random numbers (each number newly generated each loop) from 0 to 19 (inclusive).
If a number is 10, stop the loop after printing it, and do not generate any further numbers.
Otherwise, generate and print a second random number before restarting the loop.
If the number 10 is never gener... | #Batch_File | Batch File | @echo off
:loop
set /a N=%RANDOM% %% 20
echo %N%
if %N%==10 exit /b
set /a N=%RANDOM% %% 20
echo %N%
goto loop | Give a code snippet in #Batch_File
Task
Show a loop which prints random numbers (each number newly generated each loop) from 0 to 19 (inclusive).
If a number is 10, stop the loop after printing it, and do not generate any further numbers.
Otherwise, generate and print a second random number before restarting the lo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Coloured_text | Terminal control/Coloured text | Task
Display a word in various colours on the terminal.
The system palette, or colours such as Red, Green, Blue, Magenta, Cyan, and Yellow can be used.
Optionally demonstrate:
How the system should determine if the terminal supports colour
Setting of the background colour
How to cause blinking or flashing (if ... | #PARI.2FGP | PARI/GP | for(b=40, 47, for(c=30, 37, printf("\e[%d;%d;1mRosetta Code\e[0m\n", c, b))) | Give a code snippet in #PARI.2FGP
Task
Display a word in various colours on the terminal.
The system palette, or colours such as Red, Green, Blue, Magenta, Cyan, and Yellow can be used.
Optionally demonstrate:
How the system should determine if the terminal supports colour
Setting of the background colour
How... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Exponentiation_operator | Exponentiation operator | Most programming languages have a built-in implementation of exponentiation.
Task
Re-implement integer exponentiation for both intint and floatint as both a procedure, and an operator (if your language supports operator definition).
If the language supports operator (or procedure) overloading, then an ov... | #Phix | Phix | with javascript_semantics
function powir(atom b, integer i)
atom res = 1
if i<0 then {b,i} = {1/b,abs(i)} end if
while i do
if and_bits(i,1) then res *= b end if
b *= b
i = floor(i/2)
end while
return res
end function
?powir(-3,-5)
?power(-3,-5)
| Give a code snippet in #Phix
Most programming languages have a built-in implementation of exponentiation.
Task
Re-implement integer exponentiation for both intint and floatint as both a procedure, and an operator (if your language supports operator definition).
If the language supports operator (or proc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/String | Literals/String | Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characters
Here document
Other tasks r... | #Standard_ML | Standard ML | - #"a";
val it = #"a" : char | Give a code snippet in #Standard_ML
Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special charact... | christopher/rosetta-code | |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and... | #Erlang | Erlang |
-module(crc32).
-export([test/0]).
test() ->
io:fwrite("~.16#~n",[erlang:crc32(<<"The quick brown fox jumps over the lazy dog">>)]).
| Give a code snippet in #Erlang
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1... | #Nim | Nim | type
SquareMatrix[N: static Positive] = array[N, array[N, float]]
Vector[N: static Positive] = array[N, float]
####################################################################################################
# Templates.
template `[]`(m: SquareMatrix; i, j: Natural): float =
## Allow to get value of an ... | Give a code snippet in #Nim
linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #PHP | PHP | $nums = array(3, 1, 4, 1, 5, 9);
if ($nums)
echo array_sum($nums) / count($nums), "\n";
else
echo "0\n"; | Give a code snippet in #PHP
Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an establ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #D | D | import std.stdio, std.range, std.traits;
/// Approximates y(t) in y'(t)=f(t,y) with y(a)=y0 and t=a..b and the step size h.
void euler(F)(in F f, in double y0, in double a, in double b, in double h) @safe
if (isCallable!F && __traits(compiles, { real r = f(0.0, 0.0); })) {
double y = y0;
foreach (immutable t;... | Give a code snippet in #D
Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/15_puzzle_solver | 15 puzzle solver | Your task is to write a program that finds a solution in the fewest moves possible single moves to a random Fifteen Puzzle Game.
For this task you will be using the following puzzle:
15 14 1 6
9 11 4 12
0 10 7 3
13 8 5 2
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 0
The output must show the moves' dir... | #Perl | Perl | use strict;
no warnings;
use enum qw(False True);
use constant Nr => <3 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3>;
use constant Nc => <3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2>;
my ($n, $m) = (0, 0);
my(@N0, @N2, @N3, @N4);
sub fY {
printf "Solution found in $n moves: %s\n", join('', @N3) and exit if $N2[$n] == 0x123456789abcdef0... | Give a code snippet in #Perl
Your task is to write a program that finds a solution in the fewest moves possible single moves to a random Fifteen Puzzle Game.
For this task you will be using the following puzzle:
15 14 1 6
9 11 4 12
0 10 7 3
13 8 5 2
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 0
The o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Vector_products | Vector products | A vector is defined as having three dimensions as being represented by an ordered collection of three numbers: (X, Y, Z).
If you imagine a graph with the x and y axis being at right angles to each other and having a third, z axis coming out of the page, then a triplet of numbers, (X, Y, Z) would repr... | #Ceylon | Ceylon | shared void run() {
alias Vector => Float[3];
function dot(Vector a, Vector b) =>
a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
function cross(Vector a, Vector b) => [
a[1] * b[2] - a[2] * b[1],
a[2] * b[0] - a[0] * b[2],
a[0] * b[1] - a[1] * b[0]
];
function scalarTriple(Vector a, Vector b, Vector c... | Give a code snippet in #Ceylon
A vector is defined as having three dimensions as being represented by an ordered collection of three numbers: (X, Y, Z).
If you imagine a graph with the x and y axis being at right angles to each other and having a third, z axis coming out of the page, then a triplet of n... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Knapsack_problem/Unbounded | Knapsack problem/Unbounded | A traveler gets diverted and has to make an unscheduled stop in what turns out to be Shangri La. Opting to leave, he is allowed to take as much as he likes of the following items, so long as it will fit in his knapsack, and he can carry it.
He knows that he can carry no more than 25 'weights' in total; and tha... | #C | C | #include <stdio.h>
#include <stdlib.h>
typedef struct {
char *name;
double value;
double weight;
double volume;
} item_t;
item_t items[] = {
{"panacea", 3000.0, 0.3, 0.025},
{"ichor", 1800.0, 0.2, 0.015},
{"gold", 2500.0, 2.0, 0.002},
};
int n = sizeof (items) / sizeof (item_t);
i... | Give a code snippet in #C
A traveler gets diverted and has to make an unscheduled stop in what turns out to be Shangri La. Opting to leave, he is allowed to take as much as he likes of the following items, so long as it will fit in his knapsack, and he can carry it.
He knows that he can carry no more than 25 'w... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Set_consolidation | Set consolidation | Given two sets of items then if any item is common to any set then the result of applying consolidation to those sets is a set of sets whose contents is:
The two input sets if no common item exists between the two input sets of items.
The single set that is the union of the two input sets if they share a common item... | #C | C | #include <stdio.h>
#define s(x) (1U << ((x) - 'A'))
typedef unsigned int bitset;
int consolidate(bitset *x, int len)
{
int i, j;
for (i = len - 2; i >= 0; i--)
for (j = len - 1; j > i; j--)
if (x[i] & x[j])
x[i] |= x[j], x[j] = x[--len];
return len;
}
void show_sets(bitset *x, int len)
{
bitset b;
... | Give a code snippet in #C
Given two sets of items then if any item is common to any set then the result of applying consolidation to those sets is a set of sets whose contents is:
The two input sets if no common item exists between the two input sets of items.
The single set that is the union of the two input sets ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Naive | Verify distribution uniformity/Naive | This task is an adjunct to Seven-sided dice from five-sided dice.
Task
Create a function to check that the random integers returned from a small-integer generator function have uniform distribution.
The function should take as arguments:
The function (or object) producing random integers.
The number of times ... | #Ring | Ring |
# Project : Verify distribution uniformity/Naive
maxrnd = 7
for r = 2 to 5
check = distcheck(pow(10,r), 0.05)
see "over " + pow(10,r) + " runs dice5 " + nl
if check
see "failed distribution check with " + check + " bin(s) out of range" + nl
else
see "passed distribution check" + nl
... | Give a code snippet in #Ring
This task is an adjunct to Seven-sided dice from five-sided dice.
Task
Create a function to check that the random integers returned from a small-integer generator function have uniform distribution.
The function should take as arguments:
The function (or object) producing random i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Knuth_shuffle | Knuth shuffle | The Knuth shuffle (a.k.a. the Fisher-Yates shuffle) is an algorithm for randomly shuffling the elements of an array.
Task
Implement the Knuth shuffle for an integer array (or, if possible, an array of any type).
Specification
Given an array items with indices ranging from 0 to last, the algorithm can be d... | #Liberty_BASIC | Liberty BASIC | 'Declared the UpperBound to prevent confusion with lots of 9's floating around....
UpperBound = 9
Dim array(UpperBound)
For i = 0 To UpperBound
array(i) = Int(Rnd(1) * 10)
Print array(i)
Next i
For i = 0 To UpperBound
'set a random value because we will need to use the same value twice
randval = Int... | Give a code snippet in #Liberty_BASIC
The Knuth shuffle (a.k.a. the Fisher-Yates shuffle) is an algorithm for randomly shuffling the elements of an array.
Task
Implement the Knuth shuffle for an integer array (or, if possible, an array of any type).
Specification
Given an array items with indices ranging... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anti-primes | Anti-primes | The anti-primes
(or highly composite numbers, sequence A002182 in the OEIS)
are the natural numbers with more factors than any smaller than itself.
Task
Generate and show here, the first twenty anti-primes.
Related tasks
Factors of an integer
Sieve of Eratosthenes
| #Nim | Nim | # First 20 antiprimes
proc countDivisors(n: int): int =
if n < 2:
return 1
var count = 2
for i in countup(2, (n / 2).toInt()):
if n %% i == 0:
count += 1
return count
proc antiPrimes(n: int) =
echo("The first ", n, " anti-primes:")
var maxDiv = 0
var count = ... | Give a code snippet in #Nim
The anti-primes
(or highly composite numbers, sequence A002182 in the OEIS)
are the natural numbers with more factors than any smaller than itself.
Task
Generate and show here, the first twenty anti-primes.
Related tasks
Factors of an integer
Sieve of Eratosthenes
| christopher/rosetta-code | |
http://rosettacode.org/wiki/M%C3%B6bius_function | Möbius function | The classical Möbius function: μ(n) is an important multiplicative function in number theory and combinatorics.
There are several ways to implement a Möbius function.
A fairly straightforward method is to find the prime factors of a positive integer n, then define μ(n) based on the sum of the primitive factors. It ha... | #Java | Java |
public class MöbiusFunction {
public static void main(String[] args) {
System.out.printf("First 199 terms of the möbius function are as follows:%n ");
for ( int n = 1 ; n < 200 ; n++ ) {
System.out.printf("%2d ", möbiusFunction(n));
if ( (n+1) % 20 == 0 ) {
... | Give a code snippet in #Java
The classical Möbius function: μ(n) is an important multiplicative function in number theory and combinatorics.
There are several ways to implement a Möbius function.
A fairly straightforward method is to find the prime factors of a positive integer n, then define μ(n) based on the sum o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Price_fraction | Price fraction | A friend of mine runs a pharmacy. He has a specialized function in his Dispensary application which receives a decimal value of currency and replaces it to a standard value. This value is regulated by a government department.
Task
Given a floating point value between 0.00 and 1.00, rescale according to ... | #K | K |
le:- 0.96 0.91 0.86 0.81 0.76 0.71 0.66 0.61 0.56 0.51 0.46 0.41 0.36 0.31 0.26 0.21 0.16 0.11 0.06 0.0
out: 1.00 0.98 0.94 0.90 0.86 0.82 0.78 0.74 0.70 0.66 0.62 0.58 0.54 0.50 0.44 0.38 0.32 0.26 0.18 0.1
pf:{out@_bin[le;-x]}'
| Give a code snippet in #K
A friend of mine runs a pharmacy. He has a specialized function in his Dispensary application which receives a decimal value of currency and replaces it to a standard value. This value is regulated by a government department.
Task
Given a floating point value between 0.00 and 1.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Go_Fish | Go Fish | Write a program to let the user play Go Fish against a computer opponent. Use the following rules:
Each player is dealt nine cards to start with.
On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more.
If t... | #Aime | Aime |
' Go Fish ~ ¡Pesca!
Const cartas = "A234567890JQK"
Declare Sub Reparto_Cartas
Declare Sub Pescar_Carta_Jug
Declare Sub Pescar_Carta_CPU
Declare Sub Comprobar_Libro_Jug
Declare Sub Comprobar_Libro_CPU
Declare Sub Comprobar_Fin_Partida
Declare Sub Intro
Dim Shared As Integer play(13), compu(13), deck(13), guess(1... | Give a code snippet in #Aime
Write a program to let the user play Go Fish against a computer opponent. Use the following rules:
Each player is dealt nine cards to start with.
On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a giv... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a ... | #C.2B.2B | C++ | template<typename T> //Detection helper struct
struct can_eat //Detects presence of non-const member function void eat()
{
private:
template<typename U, void (U::*)()> struct SFINAE {};
template<typename U> static char Test(SFINAE<U, &U::eat>*);
template<typename U> static int Test(...);
public:
... | Give a code snippet in #C.2B.2B
Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Polymorphism | Polymorphism | Task
Create two classes Point(x,y) and Circle(x,y,r) with a polymorphic function print, accessors for (x,y,r), copy constructor, assignment and destructor and every possible default constructors
| #Golo | Golo | #!/usr/bin/env golosh
----
This module demonstrates Golo's version of polymorphism.
----
module Polymorphism
# Each struct automatically gets a constructor and also accessor and assignment methods for each field.
# For example, the constructor for Point is Point(1, 2)
# and the accessor methods are x() and y()
# and ... | Give a code snippet in #Golo
Task
Create two classes Point(x,y) and Circle(x,y,r) with a polymorphic function print, accessors for (x,y,r), copy constructor, assignment and destructor and every possible default constructors
| christopher/rosetta-code | |
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 ... | #Fortran | Fortran | XMULTF(X,Y)=X*Y | Give a code snippet in #Fortran
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 distrac... | christopher/rosetta-code | |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
... | #Mercury | Mercury | :- module fizzbuzz.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module int, string, bool.
:- func fizz(int) = bool.
fizz(N) = ( if N mod 3 = 0 then yes else no ).
:- func buzz(int) = bool.
buzz(N) = ( if N mod 5 = 0 then yes else no ).
% N ... | Give a code snippet in #Mercury
Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pernicious_numbers | Pernicious numbers | A pernicious number is a positive integer whose population count is a prime.
The population count is the number of ones in the binary representation of a non-negative integer.
Example
22 (which is 10110 in binary) has a population count of 3, which is prime, and therefore
22 is a pe... | #Seed7 | Seed7 | $ include "seed7_05.s7i";
const set of integer: primes is {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61};
const func integer: popcount (in integer: number) is
return card(bitset(number));
const proc: main is func
local
var integer: num is 0;
var integer: count is 0;
begin
f... | Give a code snippet in #Seed7
A pernicious number is a positive integer whose population count is a prime.
The population count is the number of ones in the binary representation of a non-negative integer.
Example
22 (which is 10110 in binary) has a population count of 3, which is prime... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Median | Averages/Median | Task[edit]
Write a program to find the median value of a vector of floating-point numbers.
The program need not handle the case where the vector is empty, but must handle the case where there are an even number of elements. In that case, return the average of the two middle values.
There are several approaches ... | #ALGOL_68 | ALGOL 68 | INT max_elements = 1000000;
# Return the k-th smallest item in array x of length len #
PROC quick_select = (INT k, REF[]REAL x) REAL:
BEGIN
PROC swap = (INT a, b) VOID:
BEGIN
REAL t = x[a];
x[a] := x[b]; x[b] := t
END;
INT left := 1, right := UPB x;
INT pos, i;
... | Give a code snippet in #ALGOL_68
Task[edit]
Write a program to find the median value of a vector of floating-point numbers.
The program need not handle the case where the vector is empty, but must handle the case where there are an even number of elements. In that case, return the average of the two middle valu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typica... | #Vlang | Vlang | import math.complex
fn main() {
a := complex.complex(1, 1)
b := complex.complex(3.14159, 1.25)
println("a: $a")
println("b: $b")
println("a + b: ${a+b}")
println("a * b: ${a*b}")
println("-a: ${a.addinv()}")
println("1 / a: ${complex.complex(1,0)/a}")
println("a̅: ... | Give a code snippet in #Vlang
A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displayst... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Voronoi_diagram | Voronoi diagram | A Voronoi diagram is a diagram consisting of a number of sites.
Each Voronoi site s also has a Voronoi cell consisting of all points closest to s.
Task
Demonstrate how to generate and display a Voroni diagram.
See algo K-means++ clustering.
| #Haskell | Haskell |
-- Compile with: ghc -O2 -fllvm -fforce-recomp -threaded --make
{-# LANGUAGE BangPatterns #-}
module Main where
import System.Random
import Data.Word
import Data.Array.Repa as Repa
import Data.Array.Repa.IO.BMP
{-# INLINE sqDistance #-}
sqDistance :: Word32 -> Word32 -> Word32 -> Word32 -> Word32
sqDistance... | Give a code snippet in #Haskell
A Voronoi diagram is a diagram consisting of a number of sites.
Each Voronoi site s also has a Voronoi cell consisting of all points closest to s.
Task
Demonstrate how to generate and display a Voroni diagram.
See algo K-means++ clustering.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #LLVM | LLVM | ; This is not strictly LLVM, as it uses the C library function "printf".
; LLVM does not provide a way to print values, so the alternative would be
; to just load the string into memory, and that would be boring.
; Additional comments have been inserted, as well as changes made from the output produced by clang such ... | Give a code snippet in #LLVM
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty ... | christopher/rosetta-code |
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