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
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|---|---|---|---|---|---|---|---|---|
http://rosettacode.org/wiki/Partition_an_integer_x_into_n_primes | Partition an integer x into n primes | Task
Partition a positive integer X into N distinct primes.
Or, to put it in another way:
Find N unique primes such that they add up to X.
Show in the output section the sum X and the N primes in ascending order separated by plus (+) signs:
• partition 99809 with 1 prime.
... | #Ruby | Ruby | require "prime"
def prime_partition(x, n)
Prime.each(x).to_a.combination(n).detect{|primes| primes.sum == x}
end
TESTCASES = [[99809, 1], [18, 2], [19, 3], [20, 4], [2017, 24],
[22699, 1], [22699, 2], [22699, 3], [22699, 4], [40355, 3]]
TESTCASES.each do |prime, num|
res = prime_partition(prime,... | Give a code snippet in #Ruby
Task
Partition a positive integer X into N distinct primes.
Or, to put it in another way:
Find N unique primes such that they add up to X.
Show in the output section the sum X and the N primes in ascending order separated by plus (+) signs:
• partitio... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Newbie | Hello world/Newbie | Task
Guide a new user of a language through the steps necessary
to install the programming language and selection of a text editor if needed,
to run the languages' example in the Hello world/Text task.
Assume the language-newbie is a programmer in another language.
Assume the language-newbie is competent in install... | #Robotic | Robotic |
* "Hello world!"
end
| Give a code snippet in #Robotic
Task
Guide a new user of a language through the steps necessary
to install the programming language and selection of a text editor if needed,
to run the languages' example in the Hello world/Text task.
Assume the language-newbie is a programmer in another language.
Assume the langua... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #PureBasic | PureBasic | Structure PPMColor
r.c
g.c
b.c
EndStructure
Procedure LoadImagePPM(Image, file$)
; Author Roger Rösch (Nickname Macros)
IDFile = ReadFile(#PB_Any, file$)
If IDFile
If CreateImage(Image, 1, 1)
Format$ = ReadString(IDFile)
ReadString(IDFile) ; skip comment
Dimensions$ = ReadString(IDFi... | Give a code snippet in #PureBasic
Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to gr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loop_over_multiple_arrays_simultaneously | Loop over multiple arrays simultaneously | Task
Loop over multiple arrays (or lists or tuples or whatever they're called in
your language) and display the i th element of each.
Use your language's "for each" loop if it has one, otherwise iterate
through the collection in order with some other loop.
For this example, loop over the arrays:
... | #Beads | Beads | beads 1 program 'Loop over multiple arrays simultaneously'
calc main_init
const
x = ['a', 'b', 'c']
y = ['A', 'B', 'C']
z = [1, 2, 3]
const largest = max(tree_hi(x), tree_hi(y), tree_hi(z))
loop reps:largest count:i //where u_cc defines what to use for undefined characters
log to_str(x[i], u_cc:' ') & to... | Give a code snippet in #Beads
Task
Loop over multiple arrays (or lists or tuples or whatever they're called in
your language) and display the i th element of each.
Use your language's "for each" loop if it has one, otherwise iterate
through the collection in order with some other loop.
For this exam... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix_transposition | Matrix transposition | Transpose an arbitrarily sized rectangular Matrix.
| #OCaml | OCaml | open Bigarray
let transpose b =
let dim1 = Array2.dim1 b
and dim2 = Array2.dim2 b in
let kind = Array2.kind b
and layout = Array2.layout b in
let b' = Array2.create kind layout dim2 dim1 in
for i=0 to pred dim1 do
for j=0 to pred dim2 do
b'.{j,i} <- b.{i,j}
done;
done;
(b')
;;
let arra... | Give a code snippet in #OCaml
Transpose an arbitrarily sized rectangular Matrix.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Magic_8-ball | Magic 8-ball | Task
Create Magic 8-Ball.
See details at: Magic 8-Ball.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurren... | #BASIC | BASIC | dim answer$(20)
answer$[0] = "It is certain."
answer$[1] = "It is decidedly so."
answer$[2] = "Without a doubt."
answer$[3] = "Yes - definitely."
answer$[4] = "You may rely on it."
answer$[5] = "As I see it, yes."
answer$[6] = "Most likely."
answer$[7] = "Outlook good."
answer$[8] = "Yes."
answer$[9] = "Signs point to ... | Give a code snippet in #BASIC
Task
Create Magic 8-Ball.
See details at: Magic 8-Ball.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinforma... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Counting_sort | Sorting algorithms/Counting 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
... | #Objeck | Objeck |
bundle Default {
class Cocktail {
function : Main(args : String[]) ~ Nil {
values := [9, 7, 10, 2, 9, 7, 4, 3, 10, 2, 7, 10];
CountingSort(values, 2, 10);
each(i : values) {
values[i]->PrintLine();
};
}
function : CountingSort(array : Int[], min : Int, max : Int) ~ Nil ... | Give a code snippet in #Objeck
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 s... | 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... | #JavaScript | JavaScript |
// Function that takes differential-equation, initial condition,
// ending x, and step size as parameters
function eulersMethod(f, x1, y1, x2, h) {
// Header
console.log("\tX\t|\tY\t");
console.log("------------------------------------");
// Initial Variables
var x=x1, y=y1;
// While we're not done yet
// ... | Give a code snippet in #JavaScript
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 f... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Balanced_brackets | Balanced brackets | Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
Examples
(empty) ... | #Befunge | Befunge | v > "KO TON" ,,,,,, v
> ~ : 25*- #v_ $ | > 25*, @
> "KO" ,, ^
> : 1991+*+- #v_ v
> \ : 1991+*+- #v_v
\ $
^ < <$< | Give a code snippet in #Befunge
Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_length | Array length | Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I befo... | #Visual_Basic | Visual Basic |
' declared in a module
Public Function LengthOfArray(ByRef arr As Variant) As Long
If IsArray(arr) Then
LengthOfArray = UBound(arr) - LBound(arr) + 1
Else
LengthOfArray = -1
End If
End Function
' somewhere in the programm
' example 1
Dim arr As Variant
arr = Array("apple", "orange")
Debug.... | Give a code snippet in #Visual_Basic
Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Lette... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Convex_hull | Convex hull | Find the points which form a convex hull from a set of arbitrary two dimensional points.
For example, given the points (16,3), (12,17), (0,6), (-4,-6), (16,6), (16,-7), (16,-3), (17,-4), (5,19), (19,-8), (3,16), (12,13), (3,-4), (17,5), (-3,15), (-3,-9), (0,11), (-9,-3), (-4,-2) and (12,10) the convex hull would be (-... | #Lua | Lua | function print_point(p)
io.write("("..p.x..", "..p.y..")")
return nil
end
function print_points(pl)
io.write("[")
for i,p in pairs(pl) do
if i>1 then
io.write(", ")
end
print_point(p)
end
io.write("]")
return nil
end
function ccw(a,b,c)
return (b.x... | Give a code snippet in #Lua
Find the points which form a convex hull from a set of arbitrary two dimensional points.
For example, given the points (16,3), (12,17), (0,6), (-4,-6), (16,6), (16,-7), (16,-3), (17,-4), (5,19), (19,-8), (3,16), (12,13), (3,-4), (17,5), (-3,15), (-3,-9), (0,11), (-9,-3), (-4,-2) and (12,10... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Wrong_ranges | Loops/Wrong ranges | Loops/Wrong ranges
You are encouraged to solve this task according to the task description, using any language you may know.
Some languages have syntax or function(s) to generate a range of numeric values from a start value, a stop value, and an increment.
The purpose of this task is to select the range syntax/functi... | #Java | Java |
import java.util.ArrayList;
import java.util.List;
public class LoopsWrongRanges {
public static void main(String[] args) {
runTest(new LoopTest(-2, 2, 1, "Normal"));
runTest(new LoopTest(-2, 2, 0, "Zero increment"));
runTest(new LoopTest(-2, 2, -1, "Increments away from stop value"));... | Give a code snippet in #Java
Loops/Wrong ranges
You are encouraged to solve this task according to the task description, using any language you may know.
Some languages have syntax or function(s) to generate a range of numeric values from a start value, a stop value, and an increment.
The purpose of this task is to ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rot-13 | Rot-13 |
Task
Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment).
Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of inpu... | #GAP | GAP | rot13 := function(s)
local upper, lower, c, n, t;
upper := "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
lower := "abcdefghijklmnopqrstuvwxyz";
t := [ ];
for c in s do
n := Position(upper, c);
if n <> fail then
Add(t, upper[((n+12) mod 26) + 1]);
else
n := Position(lower, c);
if n <> fail then
... | Give a code snippet in #GAP
Task
Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment).
Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 e... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abundant,_deficient_and_perfect_number_classifications | Abundant, deficient and perfect number classifications | These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficient (OEIS A005100).
if P(n)... | #Bracmat | Bracmat | ( clk$:?t0
& ( multiples
= prime multiplicity
. !arg:(?prime.?multiplicity)
& !multiplicity:0
& 1
| !prime^!multiplicity*(.!multiplicity)
+ multiples$(!prime.-1+!multiplicity)
)
& ( P
= primeFactors prime exp poly S
. !arg^1/67:?primeFactors
& ( !primeFactor... | Give a code snippet in #Bracmat
These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficie... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Inheritance/Multiple | Inheritance/Multiple | Multiple inheritance allows to specify that one class is a subclass of several other classes.
Some languages allow multiple inheritance for arbitrary classes, others restrict it to interfaces, some don't allow it at all.
Task
Write two classes (or interfaces) Camera and MobilePhone, then write a class Camer... | #E | E | def minherit(self, supers) {
def forwarder match [verb, args] {
escape __return {
if (verb == "__respondsTo") {
def [verb, arity] := args
for super ? (super.__respondsTo(verb, arity)) in supers {
return true
}
re... | Give a code snippet in #E
Multiple inheritance allows to specify that one class is a subclass of several other classes.
Some languages allow multiple inheritance for arbitrary classes, others restrict it to interfaces, some don't allow it at all.
Task
Write two classes (or interfaces) Camera and MobilePhone,... | 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)
... | #Pike | Pike | int main(){
for(int i = 1; i <= 100; i++) {
if(i % 15 == 0) {
write("FizzBuzz\n");
} else if(i % 3 == 0) {
write("Fizz\n");
} else if(i % 5 == 0) {
write("Buzz\n");
} else {
write(i + "\n");
}
}
} | Give a code snippet in #Pike
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Totient_function | Totient function | The totient function is also known as:
Euler's totient function
Euler's phi totient function
phi totient function
Φ function (uppercase Greek phi)
φ function (lowercase Greek phi)
Definitions (as per number theory)
The totient function:
counts the integers up to a given positiv... | #C.23 | C# | using static System.Console;
using static System.Linq.Enumerable;
public class Program
{
static void Main()
{
for (int i = 1; i <= 25; i++) {
int t = Totient(i);
WriteLine(i + "\t" + t + (t == i - 1 ? "\tprime" : ""));
}
WriteLine();
for (int i = 100; i ... | Give a code snippet in #C.23
The totient function is also known as:
Euler's totient function
Euler's phi totient function
phi totient function
Φ function (uppercase Greek phi)
φ function (lowercase Greek phi)
Definitions (as per number theory)
The totient function:
counts the ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Greyscale_bars/Display | Greyscale bars/Display | The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display.
For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right ha... | #PureBasic | PureBasic | EnableExplicit
Macro Check(Function)
If Not Function : End : EndIf
EndMacro
Check(InitKeyboard()) ; Cannot initialize keyboard
Check(InitSprite()) ; Cannot initialize sprite/screen library
Check(ExamineDesktops()) ; Cannot retrieve informations about desktops
Define.i iHeight, iWidth, iDepth
iHeight = D... | Give a code snippet in #PureBasic
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display.
For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/Integer | Literals/Integer | Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be interpreted by the compiler or... | #HicEst | HicEst | U8 i; // 8 bit integer
U16 i; // 16 bit integer
U32 i; // 32 bit integer
U64 i; // 64 bit integer | Give a code snippet in #HicEst
Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should b... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Vogel%27s_approximation_method | Vogel's approximation method | Vogel's Approximation Method (VAM) is a technique for finding a good initial feasible solution to an allocation problem.
The powers that be have identified 5 tasks that need to be solved urgently. Being imaginative chaps, they have called them “A”, “B”, “C”, “D”, and “E”. They estimate that:
A will require 30 hours ... | #J | J | vam=:1 :0
:
exceeding=. 0 <. -&(+/)
D=. x,y exceeding x NB. x: demands
S=. y,x exceeding y NB. y: sources
C=. (m,.0),0 NB. m: costs
B=. 1+>./,C NB. bigger than biggest cost
mincost=. <./@-.&0 NB. smallest non-zero cost
penalty=. |@(B * 2 -/@{. /:~ -. 0:)"1 - mincost"1
R=. C*0
while. 0 ... | Give a code snippet in #J
Vogel's Approximation Method (VAM) is a technique for finding a good initial feasible solution to an allocation problem.
The powers that be have identified 5 tasks that need to be solved urgently. Being imaginative chaps, they have called them “A”, “B”, “C”, “D”, and “E”. They estimate that:... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow ... | #Haskell | Haskell |
import Data.CReal
phi = (1 + sqrt 5) / 2
fib :: (Integral b) => b -> CReal 0
fib n = (phi^^n - (-phi)^^(-n))/sqrt 5
| Give a code snippet in #Haskell
The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abbreviations,_automatic | Abbreviations, automatic | The use of abbreviations (also sometimes called synonyms, nicknames, AKAs, or aliases) can be an
easy way to add flexibility when specifying or using commands, sub─commands, options, etc.
It would make a list of words easier to maintain (as words are added, changed, and/or deleted) if
the minimum abbrevia... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language |
(*This function gives all 'heads' of str of length 1 to maxLength. Since the input data was formatted to use underscores in place of spaces, there is an edge case where distinct abbreviations derived from the input data would actually not be distinct in the 'real' abbreviations. See further comments below regarding t... | Give a code snippet in #Mathematica.2FWolfram_Language
The use of abbreviations (also sometimes called synonyms, nicknames, AKAs, or aliases) can be an
easy way to add flexibility when specifying or using commands, sub─commands, options, etc.
It would make a list of words easier to maintain (as words are a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Nth_root | Nth root | Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| #Phix | Phix | with javascript_semantics
function pow_(atom x, integer e)
atom r = 1
for i=1 to e do
r *= x
end for
return r
end function
function nth_root(atom y, n)
atom eps = 1e-15, -- relative accuracy
x = 1
while 1 do
-- atom d = ( y / power(x,n-1) - x ) / n
atom d = ( y ... | Give a code snippet in #Phix
Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Descending_primes | Descending primes | Generate and show all primes with strictly descending decimal digits.
See also
OEIS:A052014 - Primes with distinct digits in descending order
Related
Ascending primes
| #Perl | Perl | #!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Descending_primes
use warnings;
use ntheory qw( is_prime );
print join('', sort map { sprintf "%9d", $_ } grep /./ && is_prime($_),
glob join '', map "{$_,}", reverse 1 .. 9) =~ s/.{45}\K/\n/gr; | Give a code snippet in #Perl
Generate and show all primes with strictly descending decimal digits.
See also
OEIS:A052014 - Primes with distinct digits in descending order
Related
Ascending primes
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function... | #F.C5.8Drmul.C3.A6 | Fōrmulæ | void local fn Function1( count as long, ... )
va_list ap
long value
va_start( ap, count )
while ( count )
value = fn va_argLong( ap )
printf @"%ld",value
count--
wend
va_end( ap )
end fn
void local fn Function2( obj as CFTypeRef, ... )
va_list ap
va_start( ap, obj )
while ( obj )
... | Give a code snippet in #F.C5.8Drmul.C3.A6
Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Fun... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Balanced_brackets | Balanced brackets | Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
Examples
(empty) ... | #Erlang | Erlang |
-module( balanced_brackets ).
-export( [generate/1, is_balanced/1, task/0] ).
generate( N ) ->
[generate_bracket(random:uniform()) || _X <- lists:seq(1, 2*N)].
is_balanced( String ) -> is_balanced_loop( String, 0 ).
task() ->
lists:foreach( fun (N) ->
String = generate( N ),
Result = is_balanced( String... | Give a code snippet in #Erlang
Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For | Loops/For | “For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code.
Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers.
... | #MATLAB_.2F_Octave | MATLAB / Octave | for i = (1:5)
output = [];
for j = (1:i)
output = [output '*'];
end
disp(output);
end | Give a code snippet in #MATLAB_.2F_Octave
“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code.
Common extensions of this allow other counting patterns or iterating over abst... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitwise_operations | Bitwise operations |
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 |... | #LiveCode | LiveCode | put "and:" && (255 bitand 2) & comma into bitops
put " or:" && (255 bitor 2) & comma after bitops
put " xor:" && (255 bitxor 2) & comma after bitops
put " not:" && (bitnot 255) after bitops
put bitops
-- Ouput
and: 2, or: 255, xor: 253, not: 4294967040 | Give a code snippet in #LiveCode
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 Operatio... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ulam_spiral_(for_primes) | Ulam spiral (for primes) | An Ulam spiral (of primes) is a method of visualizing primes when expressed in a (normally counter-clockwise) outward spiral (usually starting at 1), constructed on a square grid, starting at the "center".
An Ulam spiral is also known as a prime spiral.
The first grid (green) is shown with sequential integers, ... | #J | J | spiral =: ,~ $ [: /: }.@(2 # >:@i.@-) +/\@# <:@+: $ (, -)@(1&,) | Give a code snippet in #J
An Ulam spiral (of primes) is a method of visualizing primes when expressed in a (normally counter-clockwise) outward spiral (usually starting at 1), constructed on a square grid, starting at the "center".
An Ulam spiral is also known as a prime spiral.
The first grid (green) is shown w... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Factors_of_a_Mersenne_number | Factors of a Mersenne number | A Mersenne number is a number in the form of 2P-1.
If P is prime, the Mersenne number may be a Mersenne prime
(if P is not prime, the Mersenne number is also not prime).
In the search for Mersenne prime numbers it is advantageous to eliminate exponents by finding a small factor before starting a, potentially lengthy,... | #Julia | Julia | # v0.6
using Primes
function mersennefactor(p::Int)::Int
q = 2p + 1
while true
if log2(q) > p / 2
return -1
elseif q % 8 in (1, 7) && Primes.isprime(q) && powermod(2, p, q) == 1
return q
end
q += 2p
end
end
for i in filter(Primes.isprime, push!(colle... | Give a code snippet in #Julia
A Mersenne number is a number in the form of 2P-1.
If P is prime, the Mersenne number may be a Mersenne prime
(if P is not prime, the Mersenne number is also not prime).
In the search for Mersenne prime numbers it is advantageous to eliminate exponents by finding a small factor before s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Thue-Morse | Thue-Morse | Task
Create a Thue-Morse sequence.
See also
YouTube entry: The Fairest Sharing Sequence Ever
YouTube entry: Math and OCD - My story with the Thue-Morse sequence
Task: Fairshare between two and more
| #PureBasic | PureBasic | EnableExplicit
Procedure.i count_bits(v.i)
Define c.i
While v
c+v&1
v>>1
Wend
ProcedureReturn c
EndProcedure
If OpenConsole()
Define n.i
For n=0 To 255
Print(Str(count_bits(n)%2))
Next
PrintN(~"\n...fin") : Input()
EndIf | Give a code snippet in #PureBasic
Task
Create a Thue-Morse sequence.
See also
YouTube entry: The Fairest Sharing Sequence Ever
YouTube entry: Math and OCD - My story with the Thue-Morse sequence
Task: Fairshare between two and more
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Straddling_checkerboard | Straddling checkerboard | Task
Implement functions to encrypt and decrypt a message using the straddling checkerboard method. The checkerboard should take a 28 character alphabet (A-Z plus a full stop and an escape character) and two different numbers representing the blanks in the first row. The output will be a series of decimal digits.
Num... | #Python | Python | T = [["79", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"],
["", "H", "O", "L", "", "M", "E", "S", "", "R", "T"],
["3", "A", "B", "C", "D", "F", "G", "I", "J", "K", "N"],
["7", "P", "Q", "U", "V", "W", "X", "Y", "Z", ".", "/"]]
def straddle(s):
return "".join(L[0]+T[0][L.index(c)] for c in... | Give a code snippet in #Python
Task
Implement functions to encrypt and decrypt a message using the straddling checkerboard method. The checkerboard should take a 28 character alphabet (A-Z plus a full stop and an escape character) and two different numbers representing the blanks in the first row. The output will be ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Floyd-Warshall_algorithm | Floyd-Warshall algorithm | The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already been checked for loops, parallel ... | #Rust | Rust | pub type Edge = (usize, usize);
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Graph<T> {
size: usize,
edges: Vec<Option<T>>,
}
impl<T> Graph<T> {
pub fn new(size: usize) -> Self {
Self {
size,
edges: std::iter::repeat_with(|| None).take(size * size).collect(),
... | Give a code snippet in #Rust
The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already bee... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Non-continuous_subsequences | Non-continuous subsequences | Consider some sequence of elements. (It differs from a mere set of elements by having an ordering among members.)
A subsequence contains some subset of the elements of this sequence, in the same order.
A continuous subsequence is one in which no elements are missing between the first and last elements of the subseque... | #Oz | Oz | declare
fun {NCSubseq SeqList}
Seq = {FS.value.make SeqList}
proc {Script Result}
%% the result is a subset of Seq
{FS.subset Result Seq}
%% at least one element of Seq is missing
local Gap in
{FS.include Gap Seq}
{FS.exclude Gap Result}
%% ... | Give a code snippet in #Oz
Consider some sequence of elements. (It differs from a mere set of elements by having an ordering among members.)
A subsequence contains some subset of the elements of this sequence, in the same order.
A continuous subsequence is one in which no elements are missing between the first and l... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Magnanimous_numbers | Magnanimous numbers | A magnanimous number is an integer where there is no place in the number where a + (plus sign) could be added between any two digits to give a non-prime sum.
E.G.
6425 is a magnanimous number. 6 + 425 == 431 which is prime; 64 + 25 == 89 which is prime; 642 + 5 == 647 which is prime.
3538 is not a magnanimous numb... | #ALGOL_W | ALGOL W | begin
% find some Magnanimous numbers - numbers where inserting a "+" between %
% any two of the digits and evaluating the sum results in a prime number %
% implements the sieve of Eratosthenes %
procedure sieve( logical array s ( * ); integer value n ) ;
begin
... | Give a code snippet in #ALGOL_W
A magnanimous number is an integer where there is no place in the number where a + (plus sign) could be added between any two digits to give a non-prime sum.
E.G.
6425 is a magnanimous number. 6 + 425 == 431 which is prime; 64 + 25 == 89 which is prime; 642 + 5 == 647 which is prime... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Search_a_list | Search a list | Task[edit]
Find the index of a string (needle) in an indexable, ordered collection of strings (haystack).
Raise an exception if the needle is missing.
If there is more than one occurrence then return the smallest index to the needle.
Extra credit
Return the largest index to a needle that has multiple occurrences in ... | #Python | Python | haystack=["Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"]
for needle in ("Washington","Bush"):
try:
print haystack.index(needle), needle
except ValueError, value_error:
print needle,"is not in haystack" | Give a code snippet in #Python
Task[edit]
Find the index of a string (needle) in an indexable, ordered collection of strings (haystack).
Raise an exception if the needle is missing.
If there is more than one occurrence then return the smallest index to the needle.
Extra credit
Return the largest index to a needle t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Concurrent_computing | Concurrent computing | Task
Using either native language concurrency syntax or freely available libraries, write a program to display the strings "Enjoy" "Rosetta" "Code", one string per line, in random order.
Concurrency syntax must use threads, tasks, co-routines, or whatever concurrency is called in your language.
| #Mercury | Mercury | :- module concurrent_computing.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is cc_multi.
:- implementation.
:- import_module thread.
main(!IO) :-
spawn(io.print_cc("Enjoy\n"), !IO),
spawn(io.print_cc("Rosetta\n"), !IO),
spawn(io.print_cc("Code\n"), !IO). | Give a code snippet in #Mercury
Task
Using either native language concurrency syntax or freely available libraries, write a program to display the strings "Enjoy" "Rosetta" "Code", one string per line, in random order.
Concurrency syntax must use threads, tasks, co-routines, or whatever concurrency is called in your... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Towers_of_Hanoi | Towers of Hanoi | Task
Solve the Towers of Hanoi problem with recursion.
| #Octave | Octave | function hanoimove(ndisks, from, to, via)
if ( ndisks == 1 )
printf("Move disk from pole %d to pole %d\n", from, to);
else
hanoimove(ndisks-1, from, via, to);
hanoimove(1, from, to, via);
hanoimove(ndisks-1, via, to, from);
endif
endfunction
hanoimove(4, 1, 2, 3); | Give a code snippet in #Octave
Task
Solve the Towers of Hanoi problem with recursion.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/String_append | String append |
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 |... | #jq | jq | "Hello" | . += ", world!"
["Hello"] | .[0] += ", world!" | .[0]
{ "greeting": "Hello"} | .greeting += ", world!" | .greeting | Give a code snippet in #jq
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
Con... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Inheritance/Single | Inheritance/Single | This task is about derived types; for implementation inheritance, see Polymorphism.
Inheritance is an operation of type algebra that creates a new type from one or several parent types.
The obtained type is called derived type.
It inherits some of the properties of its parent types.
Usually inherited properties... | #Oberon | Oberon | MODULE Animals;
TYPE
Animal = RECORD END;
Dog = RECORD (Animal) END;
Cat = RECORD (Animal) END;
Lab = RECORD (Dog) END;
Collie = RECORD (Dog) END;
END Animals.
| Give a code snippet in #Oberon
This task is about derived types; for implementation inheritance, see Polymorphism.
Inheritance is an operation of type algebra that creates a new type from one or several parent types.
The obtained type is called derived type.
It inherits some of the properties of its parent type... | 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... | #NS-HUBASIC | NS-HUBASIC | 10 S$=""
20 IF S$<>"" THEN O$="NOT "
30 PRINT "THE STRING IS "O$"EMPTY." | Give a code snippet in #NS-HUBASIC
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/Doubly-linked_list/Traversal | Doubly-linked list/Traversal | Traverse from the beginning of a doubly-linked list to the end, and from the end to the beginning.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Def... | #Oberon-2 | Oberon-2 |
MODULE Collections;
IMPORT Box;
TYPE
Action = PROCEDURE (o: Box.Object);
PROCEDURE (dll: DLList) GoForth*(do: Action);
VAR
iter: Node;
BEGIN
iter := dll.first;
WHILE iter # NIL DO
do(iter.value);
iter := iter.next
END
END GoForth;
PROCEDURE (dll: DLList) GoBack*(do: Action);
VAR
i... | Give a code snippet in #Oberon-2
Traverse from the beginning of a doubly-linked list to the end, and from the end to the beginning.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Elemen... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Take_notes_on_the_command_line | Take notes on the command line | Take notes on the command line is part of Short Circuit's Console Program Basics selection.
Invoking NOTES without commandline arguments displays the current contents of the local NOTES.TXT if it exists.
If NOTES has arguments, the current date and time are appended to the local NOTES.TXT followed by a newline.
Then al... | #SNOBOL4 | SNOBOL4 | #! /usr/local/bin/snobol4 -b
a = 2 ;* skip '-b' parameter
notefile = "notes.txt"
while args = args host(2,a = a + 1) " " :s(while)
ident(args) :f(append)
noparms input(.notes,io_findunit(),,notefile) :s(display)f(end)
display output = notes :s(display)
endfile(notes) :(end)
append output(.notes,io_findun... | Give a code snippet in #SNOBOL4
Take notes on the command line is part of Short Circuit's Console Program Basics selection.
Invoking NOTES without commandline arguments displays the current contents of the local NOTES.TXT if it exists.
If NOTES has arguments, the current date and time are appended to the local NOTES.T... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Last_Friday_of_each_month | Last Friday of each month | Task
Write a program or a script that returns the date of the last Fridays of each month of a given year.
The year may be given through any simple input method in your language (command line, std in, etc).
Example of an expected output:
./last_fridays 2012
2012-01-27
2012-02-24
2012-03-30
2012-04-27
2012-05-25
20... | #Nim | Nim | import os, strutils, times
const
DaysInMonth: array[Month, int] = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
DayDiffs: array[WeekDay, int] = [3, 4, 5, 6, 0, 1, 2]
let year = paramStr(1).parseInt
for month in mJan..mDec:
var lastDay = DaysInMonth[month]
if month == mFeb and year.isLeapYear: lastDay ... | Give a code snippet in #Nim
Task
Write a program or a script that returns the date of the last Fridays of each month of a given year.
The year may be given through any simple input method in your language (command line, std in, etc).
Example of an expected output:
./last_fridays 2012
2012-01-27
2012-02-24
2012-0... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #Icon_and_Unicon | Icon and Unicon | procedure main(A)
write("Mean angle is ",meanAngle(A))
end
procedure meanAngle(A)
every (sumSines := 0.0) +:= sin(dtor(!A))
every (sumCosines := 0.0) +:= cos(dtor(!A))
return rtod(atan(sumSines/*A,sumCosines/*A))
end | Give a code snippet in #Icon_and_Unicon
When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dutch_national_flag_problem | Dutch national flag problem |
The Dutch national flag is composed of three coloured bands in the order:
red (top)
then white, and
lastly blue (at the bottom).
The problem posed by Edsger Dijkstra is:
Given a number of red, blue and white balls in random order, arrange them in the order of the colours in the Dutch national fla... | #F.23 | F# | (* Since the task description here does not impose Dijsktra's original restrictions
* Changing the order is only allowed by swapping 2 elements
* Every element must only be inspected once
we have several options ...
One way -- especially when we work with immutable data structures --
is to scan the uno... | Give a code snippet in #F.23
The Dutch national flag is composed of three coloured bands in the order:
red (top)
then white, and
lastly blue (at the bottom).
The problem posed by Edsger Dijkstra is:
Given a number of red, blue and white balls in random order, arrange them in the order of the col... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #JavaScript | JavaScript | var funcs = [];
for (var i = 0; i < 10; i++) {
funcs.push( (function(i) {
return function() { return i * i; }
})(i) );
}
window.alert(funcs[3]()); // alerts "9" | Give a code snippet in #JavaScript
Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.... | #OoRexx | OoRexx |
/* Weasel.rex - Me thinks thou art a weasel. - G,M.D. - 2/25/2011 */
arg C M
/* C is the number of children parent produces each generation. */
/* M is the mutation rate of each gene (character) */
call initialize
generation = 0
do until parent = target
most_fitness = fitness(parent)
most_fit = parent
... | Give a code snippet in #OoRexx
Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of it... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #zonnon | zonnon |
module Main;
import System;
var
now: System.DateTime;
begin
now := System.DateTime.Now;
System.Console.WriteLine(now.ToString("yyyy-MM-dd");
System.Console.WriteLine("{0}, {1}",now.DayOfWeek,now.ToString("MMMM dd, yyyy"));
end Main.
| Give a code snippet in #zonnon
This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Animate_a_pendulum | Animate a pendulum |
One good way of making an animation is by simulating a physical system and illustrating the variables in that system using a dynamically changing graphical display.
The classic such physical system is a simple gravity pendulum.
Task
Create a simple physical model of a pendulum and animate it.
| #Prolog | Prolog | :- use_module(library(pce)).
pendulum :-
new(D, window('Pendulum')),
send(D, size, size(560, 300)),
new(Line, line(80, 50, 480, 50)),
send(D, display, Line),
new(Circle, circle(20)),
send(Circle, fill_pattern, colour(@default, 0, 0, 0)),
new(Boule, circle(60)),
send(Boule, fill_pattern, colour(@default, 0, ... | Give a code snippet in #Prolog
One good way of making an animation is by simulating a physical system and illustrating the variables in that system using a dynamically changing graphical display.
The classic such physical system is a simple gravity pendulum.
Task
Create a simple physical model of a pendulum and ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Integer_sequence | Integer sequence | Task
Create a program that, when run, would display all integers from 1 to ∞ (or any relevant implementation limit), in sequence (i.e. 1, 2, 3, 4, etc) if given enough time.
An example may not be able to reach arbitrarily-large numbers based on implementations limits. For example, if integer... | #jq | jq | def iota: ., (. + 1 | iota);
0 | iota | Give a code snippet in #jq
Task
Create a program that, when run, would display all integers from 1 to ∞ (or any relevant implementation limit), in sequence (i.e. 1, 2, 3, 4, etc) if given enough time.
An example may not be able to reach arbitrarily-large numbers based on implementations limit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Color_of_a_screen_pixel | Color of a screen pixel | Task
Get color information from an arbitrary pixel on the screen, such as the current location of the mouse cursor.
The mouse cursor may or may not have to be active in a GUI created by your program. These functions are OS related.
| #PicoLisp | PicoLisp | (in '(grabc)
(mapcar hex (cdr (line NIL 1 2 2 2))) ) | Give a code snippet in #PicoLisp
Task
Get color information from an arbitrary pixel on the screen, such as the current location of the mouse cursor.
The mouse cursor may or may not have to be active in a GUI created by your program. These functions are OS related.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Ringing_the_terminal_bell | Terminal control/Ringing the terminal bell |
Task
Make the terminal running the program ring its "bell".
On modern terminal emulators, this may be done by playing some other sound which might or might not be configurable, or by flashing the title bar or inverting the colors of the screen, but was classically a physical bell within the terminal. It is usua... | #Arturo | Arturo | print "\a" | Give a code snippet in #Arturo
Task
Make the terminal running the program ring its "bell".
On modern terminal emulators, this may be done by playing some other sound which might or might not be configurable, or by flashing the title bar or inverting the colors of the screen, but was classically a physical bell w... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.... | #Java | Java |
import java.util.Random;
public class EvoAlgo {
static final String target = "METHINKS IT IS LIKE A WEASEL";
static final char[] possibilities = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ".toCharArray();
static int C = 100; //number of spawn per generation
static double minMutateRate = 0.09;
static int perfectFitness =... | Give a code snippet in #Java
Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Walk_a_directory/Non-recursively | Walk a directory/Non-recursively | Task
Walk a given directory and print the names of files matching a given pattern.
(How is "pattern" defined? substring match? DOS pattern? BASH pattern? ZSH pattern? Perl regular expression?)
Note: This task is for non-recursive methods. These tasks should read a single directory, not an entire directory tree.
... | #Emacs_Lisp | Emacs Lisp | (directory-files "/some/dir/name"
nil ;; just the filenames, not full paths
"\\.c\\'" ;; regexp
t) ;; don't sort the filenames
;;=> ("foo.c" "bar.c" ...) | Give a code snippet in #Emacs_Lisp
Task
Walk a given directory and print the names of files matching a given pattern.
(How is "pattern" defined? substring match? DOS pattern? BASH pattern? ZSH pattern? Perl regular expression?)
Note: This task is for non-recursive methods. These tasks should read a single direct... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #Visual_Basic_.NET | Visual Basic .NET | 'Current Directory
Console.WriteLine(If(IO.Directory.Exists("docs"), "directory exists", "directory doesn't exists"))
Console.WriteLine(If(IO.Directory.Exists("output.txt"), "file exists", "file doesn't exists"))
'Root
Console.WriteLine(If(IO.Directory.Exists("\docs"), "directory exists", "directory doesn't exists"))... | Give a code snippet in #Visual_Basic_.NET
Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Keyboard_input/Flush_the_keyboard_buffer | Keyboard input/Flush the keyboard buffer | Flush the keyboard buffer.
This reads characters from the keyboard input and
discards them until there are no more currently buffered,
and then allows the program to continue.
The program must not wait for users to type anything.
| #Ring | Ring |
# Project: Keyboard input/Flush the keyboard buffer
Fflush(stdin)
| Give a code snippet in #Ring
Flush the keyboard buffer.
This reads characters from the keyboard input and
discards them until there are no more currently buffered,
and then allows the program to continue.
The program must not wait for users to type anything.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequ... | #Go | Go | package main
import (
"fmt"
"math"
)
func main() {
for i := int8(0); ; i++ {
fmt.Printf("%o\n", i)
if i == math.MaxInt8 {
break
}
}
} | Give a code snippet in #Go
Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
R... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Truncatable_primes | Truncatable primes | A truncatable prime is a prime number that when you successively remove digits from one end of the prime, you are left with a new prime number.
Examples
The number 997 is called a left-truncatable prime as the numbers 997, 97, and 7 are all prime.
The number 7393 is a right-truncatable prime as the numbers 7393, 7... | #PureBasic | PureBasic | #MaxLim = 999999
Procedure is_Prime(n)
If n<=1 : ProcedureReturn #False
ElseIf n<4 : ProcedureReturn #True
ElseIf n%2=0: ProcedureReturn #False
ElseIf n<9 : ProcedureReturn #True
ElseIf n%3=0: ProcedureReturn #False
Else
Protected r=Round(Sqr(n),#PB_Round_Down)
Protected f=5
While f<=r
... | Give a code snippet in #PureBasic
A truncatable prime is a prime number that when you successively remove digits from one end of the prime, you are left with a new prime number.
Examples
The number 997 is called a left-truncatable prime as the numbers 997, 97, and 7 are all prime.
The number 7393 is a right-trunc... | 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... | #Racket | Racket |
#lang racket
(define a 3+4i)
(define b 8+0i)
(+ a b) ; addition
(- a b) ; subtraction
(/ a b) ; division
(* a b) ; multiplication
(- a) ; negation
(/ 1 a) ; reciprocal
(conjugate a) ; conjugation
| Give a code snippet in #Racket
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
{\displays... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stem-and-leaf_plot | Stem-and-leaf plot | Create a well-formatted stem-and-leaf plot from the following data set, where the leaves are the last digits:
12 127 28 42 39 113 42 18 44 118 44 37 113 124 37 48 127 36 29 31 125 139 131 115 105 132 104 123 35 113 122 42 117 119 58 109 23 105 63 27 44 105 99 41 128 121 116 125 32 61 37 127 29 113 121 58 114 126 53 11... | #Julia | Julia |
function stemleaf{T<:Real}(a::Array{T,1}, leafsize=1)
ls = 10^int(log10(leafsize))
(stem, leaf) = divrem(sort(int(a/ls)), 10)
leaf[sign(stem) .== -1] *= -1
negzero = leaf .< 0
if any(negzero)
leaf[negzero] *= -1
nz = @sprintf "%10s | " "-0"
nz *= join(map(string, leaf[negze... | Give a code snippet in #Julia
Create a well-formatted stem-and-leaf plot from the following data set, where the leaves are the last digits:
12 127 28 42 39 113 42 18 44 118 44 37 113 124 37 48 127 36 29 31 125 139 131 115 105 132 104 123 35 113 122 42 117 119 58 109 23 105 63 27 44 105 99 41 128 121 116 125 32 61 37 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Program_termination | Program termination |
Task
Show the syntax for a complete stoppage of a program inside a conditional.
This includes all threads/processes which are part of your program.
Explain the cleanup (or lack thereof) caused by the termination (allocated memory, database connections, open files, object finalizers/destructors, run-on-exit hooks... | #Prolog | Prolog | halt. | Give a code snippet in #Prolog
Task
Show the syntax for a complete stoppage of a program inside a conditional.
This includes all threads/processes which are part of your program.
Explain the cleanup (or lack thereof) caused by the termination (allocated memory, database connections, open files, object finalizer... | 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
... | #Ursala | Ursala | #import std
mergesort "p" = @iNCS :-0 ~&B^?a\~&YaO "p"?abh/~&alh2faltPrXPRC ~&arh2falrtPXPRC
#show+
example = mergesort(lleq) <'zoh','zpb','hhh','egi','bff','cii','yid'> | Give a code snippet in #Ursala
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 s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/24_game/Solve | 24 game/Solve | task
Write a program that takes four digits, either from user input or by random generation, and computes arithmetic expressions following the rules of the 24 game.
Show examples of solutions generated by the program.
Related task
Arithmetic Evaluator
| #Swift | Swift |
import Darwin
import Foundation
var solution = ""
println("24 Game")
println("Generating 4 digits...")
func randomDigits() -> [Int] {
var result = [Int]()
for i in 0 ..< 4 {
result.append(Int(arc4random_uniform(9)+1))
}
return result
}
// Choose 4 digits
let digits = randomDigits()
print("Make 2... | Give a code snippet in #Swift
task
Write a program that takes four digits, either from user input or by random generation, and computes arithmetic expressions following the rules of the 24 game.
Show examples of solutions generated by the program.
Related task
Arithmetic Evaluator
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Unicode_output | Terminal control/Unicode output | The task is to check that the terminal supports Unicode output, before outputting a Unicode character. If the terminal supports Unicode, then the terminal should output a Unicode delta (U+25b3). If the terminal does not support Unicode, then an appropriate error should be raised.
Note that it is permissible to use sys... | #Python | Python | import sys
if "UTF-8" in sys.stdout.encoding:
print("△")
else:
raise Exception("Terminal can't handle UTF-8") | Give a code snippet in #Python
The task is to check that the terminal supports Unicode output, before outputting a Unicode character. If the terminal supports Unicode, then the terminal should output a Unicode delta (U+25b3). If the terminal does not support Unicode, then an appropriate error should be raised.
Note t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Show_ASCII_table | Show ASCII table | Task
Show the ASCII character set from values 32 to 127 (decimal) in a table format.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioin... | #Java | Java |
public class ShowAsciiTable {
public static void main(String[] args) {
for ( int i = 32 ; i <= 127 ; i++ ) {
if ( i == 32 || i == 127 ) {
String s = i == 32 ? "Spc" : "Del";
System.out.printf("%3d: %s ", i, s);
}
else {
... | Give a code snippet in #Java
Task
Show the ASCII character set from values 32 to 127 (decimal) in a table format.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Extend_your_language | Extend your language | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Some programming languages allow you to extend the language. While this can be done to a certain degree in most languages (e.g. by using macros), other langua... | #Quackery | Quackery | ( --------------------- version #1 --------------------- )
[ not swap not 1 << |
]'[ swap peek do ] is if2.1 ( b b --> )
[ if2.1
[ [ say "true and true" ]
[ say "true and false" ]
[ say "false and true" ]
[ say "false and false" ] ]
cr ] ... | Give a code snippet in #Quackery
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Some programming languages allow you to extend the language. While this can be done to a certain degree in most languages (e... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anonymous_recursion | Anonymous recursion | While implementing a recursive function, it often happens that we must resort to a separate helper function to handle the actual recursion.
This is usually the case when directly calling the current function would waste too many resources (stack space, execution time), causing unwanted side-effects, and/or the f... | #Axiom | Axiom | #include "axiom"
Z ==> Integer;
fib(x:Z):Z == {
x <= 0 => error "argument outside of range";
f(n:Z,v1:Z,v2:Z):Z == if n<2 then v2 else f(n-1,v2,v1+v2);
f(x,1,1);
} | Give a code snippet in #Axiom
While implementing a recursive function, it often happens that we must resort to a separate helper function to handle the actual recursion.
This is usually the case when directly calling the current function would waste too many resources (stack space, execution time), causing unwant... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Conjugate_transpose | Conjugate transpose | Suppose that a matrix
M
{\displaystyle M}
contains complex numbers. Then the conjugate transpose of
M
{\displaystyle M}
is a matrix
M
H
{\displaystyle M^{H}}
containing the complex conjugates of the matrix transposition of
M
{\displaystyle M}
.
(
M
H
)
j
i
=
M
i
j
... | #D | D | import std.stdio, std.complex, std.math, std.range, std.algorithm,
std.numeric;
T[][] conjugateTranspose(T)(in T[][] m) pure nothrow @safe {
auto r = new typeof(return)(m[0].length, m.length);
foreach (immutable nr, const row; m)
foreach (immutable nc, immutable c; row)
r[nc][nr] = ... | Give a code snippet in #D
Suppose that a matrix
M
{\displaystyle M}
contains complex numbers. Then the conjugate transpose of
M
{\displaystyle M}
is a matrix
M
H
{\displaystyle M^{H}}
containing the complex conjugates of the matrix transposition of
M
{\displaystyle M}
.
(
M
H... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Numeric_error_propagation | Numeric error propagation | If f, a, and b are values with uncertainties σf, σa, and σb, and c is a constant;
then if f is derived from a, b, and c in the following ways,
then σf can be calculated as follows:
Addition/Subtraction
If f = a ± c, or f = c ± a then σf = σa
If f = a ± b then... | #Phix | Phix | with javascript_semantics
enum VALUE, DELTA
type imprecise(object imp)
return sequence(imp) and atom(imp[VALUE]) and atom(imp[DELTA])
end type
function sqr(atom a)
return a*a
end function
function imprecise_add(imprecise a, b)
atom delta = sqrt(sqr(a[DELTA]) + sqr(b[DELTA]))
imprecise ret = {a[VA... | Give a code snippet in #Phix
If f, a, and b are values with uncertainties σf, σa, and σb, and c is a constant;
then if f is derived from a, b, and c in the following ways,
then σf can be calculated as follows:
Addition/Subtraction
If f = a ± c, or f = c ± a then ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #HolyC | HolyC | Dir; | Give a code snippet in #HolyC
Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Multiplication_tables | Multiplication tables | Task
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
| #Picat | Picat | go =>
N=12,
make_table(N),
nl.
%
% Make a table of size N
%
make_table(N) =>
printf(" "),
foreach(I in 1..N) printf("%4w", I) end,
nl,
println(['-' : _ in 1..(N+1)*4+1]),
foreach(I in 1..N)
printf("%2d | ", I),
foreach(J in 1..N)
if J>=I then
printf("%4w", I*J)
else
... | Give a code snippet in #Picat
Task
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Image_noise | Image noise | Generate a random black and white 320x240 image continuously,
showing FPS (frames per second).
A sample image
| #Nim | Nim | import times
import opengl
import opengl/glut
const
W = 320
H = 240
SLen = W * H div sizeof(int)
var
frame = 0
bits: array[SLen, uint]
last, start: Time
#---------------------------------------------------------------------------------------------------
proc render() {.cdecl.} =
## Render the wi... | Give a code snippet in #Nim
Generate a random black and white 320x240 image continuously,
showing FPS (frames per second).
A sample image
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Nth_root | Nth root | Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| #AArch64_Assembly | AArch64 Assembly |
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program nroot64.s */
/* link with gcc. Use C function for display float */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language... | Give a code snippet in #AArch64_Assembly
Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/Integer | Literals/Integer | Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be interpreted by the compiler or... | #Python | Python | >>> # Bin(leading 0b or 0B), Oct(leading 0o or 0O), Dec, Hex(leading 0x or 0X), in order:
>>> 0b1011010111 == 0o1327 == 727 == 0x2d7
True
>>> | Give a code snippet in #Python
Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should b... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_concatenation | String concatenation | String concatenation
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Create a string variable equal to any text value.
Create another string variable whose value is the original variable concatenated with another string literal.
To illustrate the operat... | #MUMPS | MUMPS | STRCAT
SET S="STRING"
WRITE !,S
SET T=S_" LITERAL"
WRITE !,T
QUIT | Give a code snippet in #MUMPS
String concatenation
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Create a string variable equal to any text value.
Create another string variable whose value is the original variable concatenated with another string lit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Search_a_list_of_records | Search a list of records | Many programming languages provide convenient ways to look for a known value in a simple list of strings or numbers.
But what if the elements of the list are themselves compound records/objects/data-structures, and the search condition is more complex than a simple equality test?
Task[edit]
Write a function/method/et... | #C.23 | C# | using System;
using System.Collections.Generic;
namespace RosettaSearchListofRecords
{
class Program
{
static void Main(string[] args)
{
var dataset = new List<Dictionary<string, object>>() {
new Dictionary<string, object> {{ "name" , "Lagos"}, {"po... | Give a code snippet in #C.23
Many programming languages provide convenient ways to look for a known value in a simple list of strings or numbers.
But what if the elements of the list are themselves compound records/objects/data-structures, and the search condition is more complex than a simple equality test?
Task[ed... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow ... | #360_Assembly | 360 Assembly | * Fibonacci sequence 05/11/2014
* integer (31 bits) = 10 decimals -> max fibo(46)
FIBONACC CSECT
USING FIBONACC,R12 base register
SAVEAREA B STM-SAVEAREA(R15) skip savearea
DC 17F'0' savearea
DC CL8'FIBONACC' eyecatcher
STM STM R14,R12,12(R13) s... | Give a code snippet in #360_Assembly
The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive soluti... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Perfect_numbers | Perfect numbers | Write a function which says whether a number is perfect.
A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself.
Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself).
Note: The faster Luca... | #OCaml | OCaml | let perf n =
let sum = ref 0 in
for i = 1 to n-1 do
if n mod i = 0 then
sum := !sum + i
done;
!sum = n | Give a code snippet in #OCaml
Write a function which says whether a number is perfect.
A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself.
Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Foreach | Loops/Foreach | Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for... | #CLU | CLU | start_up = proc ()
po: stream := stream$primary_output()
words: array[string] := array[string]$
["enemy", "lasagna", "robust", "below", "wax"]
for word: string in array[string]$elements(words) do
stream$putl(po, word)
end
end start_up | Give a code snippet in #CLU
Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/D... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sequence_of_primorial_primes | Sequence of primorial primes | The sequence of primorial primes is given as the increasing values of n where primorial(n) ± 1 is prime.
Noting that the n'th primorial is defined as the multiplication of the smallest n primes, the sequence is of the number of primes, in order that when multiplied together is one-off being a prime number itself.
T... | #Wren | Wren | import "/big" for BigInt
import "/math" for Int
import "io" for Stdout
var primes = Int.primeSieve(4000) // more than enough for this task
System.print("The indices of the first 15 primorial numbers, p, where p + 1 or p - 1 is prime are:")
var count = 0
var prod = BigInt.two
for (i in 1...primes.count) {
if ((pro... | Give a code snippet in #Wren
The sequence of primorial primes is given as the increasing values of n where primorial(n) ± 1 is prime.
Noting that the n'th primorial is defined as the multiplication of the smallest n primes, the sequence is of the number of primes, in order that when multiplied together is one-off bei... | christopher/rosetta-code | |
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.... | #OCaml | OCaml | let div a b = a / b
let () =
try let _ = div 3 0 in ()
with e ->
prerr_endline(Printexc.to_string e);
Printexc.print_backtrace stderr;
;; | Give a code snippet in #OCaml
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 pl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Menu | Menu | Task
Given a prompt and a list containing a number of strings of which one is to be selected, create a function that:
prints a textual menu formatted as an index value followed by its corresponding string for each item in the list;
prompts the user to enter a number;
returns the string corresponding to the selecte... | #Elixir | Elixir | defmodule Menu do
def select(_, []), do: ""
def select(prompt, items) do
IO.puts ""
Enum.with_index(items) |> Enum.each(fn {item,i} -> IO.puts " #{i}. #{item}" end)
answer = IO.gets("#{prompt}: ") |> String.strip
case Integer.parse(answer) do
{num, ""} when num in 0..length(items)-1 -> Enum.at... | Give a code snippet in #Elixir
Task
Given a prompt and a list containing a number of strings of which one is to be selected, create a function that:
prints a textual menu formatted as an index value followed by its corresponding string for each item in the list;
prompts the user to enter a number;
returns the str... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation langu... | #Crystal | Crystal | class StdDevAccumulator
def initialize
@n, @sum, @sum2 = 0, 0.0, 0.0
end
def <<(num)
@n += 1
@sum += num
@sum2 += num**2
Math.sqrt (@sum2 * @n - @sum**2) / @n**2
end
end
sd = StdDevAccumulator.new
i = 0
[2,4,4,4,5,5,7,9].each { |n| puts "adding #{n}: stddev of #{i+=1} samples is #{sd << ... | Give a code snippet in #Crystal
Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the fun... | christopher/rosetta-code | |
http://rosettacode.org/wiki/A%2BB | A+B | A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separated by space(s):
(
−
1000
≤... | #AsciiDots | AsciiDots |
&-#$-\
.-#?-[+]
.-#?--/
| Give a code snippet in #AsciiDots
A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, sepa... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Middle_three_digits | Middle three digits | Task
Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible.
Note: The order of the middle digits should be preserved.
Your function should be tested with the following values;... | #Batch_File | Batch File | @echo off
setlocal enabledelayedexpansion
%== Initialization ==%
set "numbers=123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0"
%== The Main Thing ==%
for %%N in (%numbers%) do (
call :middle3 %%N
)
echo.
pause
exit /b 0
%==/The Main Thing ==%
%== The Proc... | Give a code snippet in #Batch_File
Task
Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible.
Note: The order of the middle digits should be preserved.
Your function should ... | 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 ... | #BASIC | BASIC | DECLARE FUNCTION multiply% (a AS INTEGER, b AS INTEGER)
FUNCTION multiply% (a AS INTEGER, b AS INTEGER)
multiply = a * b
END FUNCTION | Give a code snippet in #BASIC
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Delete_a_file | Delete a file | Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Icon_and_Unicon | Icon and Unicon | every dir := !["./","/"] do {
remove(f := dir || "input.txt") |stop("failure for file remove ",f)
rmdir(f := dir || "docs") |stop("failure for directory remove ",f)
}
| Give a code snippet in #Icon_and_Unicon
Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/AST_interpreter | Compiler/AST interpreter | An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer is as simple as (pseudo code)
de... | #Scala | Scala |
package xyz.hyperreal.rosettacodeCompiler
import scala.collection.mutable
import scala.io.Source
object ASTInterpreter {
def fromStdin = fromSource(Source.stdin)
def fromString(src: String) = fromSource(Source.fromString(src))
def fromSource(s: Source) = {
val lines = s.getLines
def load: No... | Give a code snippet in #Scala
An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Happy_numbers | Happy numbers | From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not inclu... | #Quackery | Quackery |
[ 0 swap
[ 10 /mod 2 **
rot + swap
dup 0 = until ]
drop ] is digitsquare ( n --> n )
[ [ digitsquare
dup 1 != while
dup 42 != while
again ]
1 = ] is happy ( n --> b )
[ [] 1
[ dip
[ 2dup size > ]
... | Give a code snippet in #Quackery
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endless... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For_with_a_specified_step | Loops/For with a specified step |
Task
Demonstrate a for-loop where the step-value is greater than one.
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 b... | #E | E | var i := 2
while (i <= 8) {
print(`$i, `)
i += 2
}
println("who do we appreciate?") | Give a code snippet in #E
Task
Demonstrate a for-loop where the step-value is greater than one.
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/Increme... | christopher/rosetta-code | |
http://rosettacode.org/wiki/A%2BB | A+B | A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separated by space(s):
(
−
1000
≤... | #Robotic | Robotic |
input string "Input A:"
set "A" to "input"
input string "Input B:"
set "B" to "input"
* "('A' + 'B')"
end
| Give a code snippet in #Robotic
A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separa... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Special_characters | Special characters | Special characters are symbols (single characters or sequences of characters) that have a "special" built-in meaning in the language and typically cannot be used in identifiers.
Escape sequences are methods that the language uses to remove the special meaning from the symbol, enabling it to be used as a normal charact... | #Julia | Julia | # defined local ie. #mylocal will fail if not defined
$ defined variable ie. $myvar will fail if not defined
= assignment
:= assign as return assigned value
? ternary conditional true ? this
| ternary else false ? this | that
|| or
&& and
! negative operator
{ open capture
} close capture
=> specify givenblock / captur... | Give a code snippet in #Julia
Special characters are symbols (single characters or sequences of characters) that have a "special" built-in meaning in the language and typically cannot be used in identifiers.
Escape sequences are methods that the language uses to remove the special meaning from the symbol, enabling it... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Primality_by_trial_division | Primality by trial division | Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other loops are allowed.
Related tasks
... | #COBOL | COBOL | Identification Division.
Program-Id. Primality-By-Subdiv.
Data Division.
Working-Storage Section.
78 True-Val Value 0.
78 False-Val Value 1.
Local-Storage Section.
01 lim Pic 9(10).
01 i Pic 9(10).
Linkage Section.
01 num Pic ... | Give a code snippet in #COBOL
Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other loops... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Law_of_cosines_-_triples | Law of cosines - triples | The Law of cosines states that for an angle γ, (gamma) of any triangle, if the sides adjacent to the angle are A and B and the side opposite is C; then the lengths of the sides are related by this formula:
A2 + B2 - 2ABcos(γ) = C2
Specific angles
For an angle of of 90º this becomes the more familiar ... | #C.2B.2B | C++ | #include <cmath>
#include <iostream>
#include <tuple>
#include <vector>
using triple = std::tuple<int, int, int>;
void print_triple(std::ostream& out, const triple& t) {
out << '(' << std::get<0>(t) << ',' << std::get<1>(t) << ',' << std::get<2>(t) << ')';
}
void print_vector(std::ostream& out, const std::vec... | Give a code snippet in #C.2B.2B
The Law of cosines states that for an angle γ, (gamma) of any triangle, if the sides adjacent to the angle are A and B and the side opposite is C; then the lengths of the sides are related by this formula:
A2 + B2 - 2ABcos(γ) = C2
Specific angles
For an angle of of 90º ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Patience_sort | Sorting algorithms/Patience 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
... | #Elixir | Elixir | defmodule Sort do
def patience_sort(list) do
piles = deal_pile(list, [])
merge_pile(piles, [])
end
defp deal_pile([], piles), do: piles
defp deal_pile([h|t], piles) do
index = Enum.find_index(piles, fn pile -> hd(pile) <= h end)
new_piles = if index, do: add_element(piles, index, h, []),
... | Give a code snippet in #Elixir
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 s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/File_size | File size | Verify the size of a file called input.txt for a file in the current working directory, and another one in the file system root.
| #K | K | _size "input.txt"
_size "/input.txt" | Give a code snippet in #K
Verify the size of a file called input.txt for a file in the current working directory, and another one in the file system root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows/Player | Bulls and cows/Player | Task
Write a player of the Bulls and Cows game, rather than a scorer. The player should give intermediate answers that respect the scores to previous attempts.
One method is to generate a list of all possible numbers that could be the answer, then to prune the list by keeping only those numbers that would give an equ... | #Red | Red | Red []
digits: charset [#"1" - #"9"] ;; bitset for parse rule in valid function
check: function [s i ][ ;; returns string with bulls -B and cows - C found
return sort append copy "" collect [
repeat pos 4 [ either ( v: pick i pos ) = pick s pos [ keep "B"][ if find s v [keep "C"] ] ]
... | Give a code snippet in #Red
Task
Write a player of the Bulls and Cows game, rather than a scorer. The player should give intermediate answers that respect the scores to previous attempts.
One method is to generate a list of all possible numbers that could be the answer, then to prune the list by keeping only those n... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Go | Go | package main
import (
"fmt"
"math"
)
// symmetric and lower use a packed representation that stores only
// the lower triangle.
type symmetric struct {
order int
ele []float64
}
type lower struct {
order int
ele []float64
}
// symmetric.print prints a square matrix from the packed ... | Give a code snippet in #Go
Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpret... | 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... | #C.2B.2B | C++ | #include <cstdio>
int main()
{
std::rename("input.txt", "output.txt");
std::rename("docs", "mydocs");
std::rename("/input.txt", "/output.txt");
std::rename("/docs", "/mydocs");
return 0;
} | Give a code snippet in #C.2B.2B
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 ... | christopher/rosetta-code |
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