task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k | response_seed stringclasses 1
value | instruction_seed stringlengths 27 14.4k | _source stringclasses 1
value |
|---|---|---|---|---|---|---|---|---|
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, gi... | #Java | Java | public static int[][] Zig_Zag(final int size)
{
int[][] data = new int[size][size];
int i = 1;
int j = 1;
for (int element = 0; element < size * size; element++)
{
data[i - 1][j - 1] = element;
if ((i + j) % 2 == 0)
{
// Even stripes
if (j < size)
j++;
else
i+= 2;
if (i > 1)
i--;
}
... | Give a code snippet in #Java
Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to enco... | 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.
... | #8080_Assembly | 8080 Assembly | exit: equ 0 ; CP/M syscall to exit
puts: equ 9 ; CP/M syscall to print a string
sfirst: equ 17 ; 'Find First' CP/M syscall
snext: equ 18 ; 'Find Next' CP/M syscall
FCB: equ 5Ch ; Location of FCB for file given on command line
org 100h
lxi d,FCB ; CP/M parses the command line for us automatically
mvi c,sfirst; and p... | Give a code snippet in #8080_Assembly
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 dir... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Check_output_device_is_a_terminal | Check output device is a terminal | Task
Demonstrate how to check whether the output device is a terminal or not.
Related task
Check input device is a terminal
| #FreeBASIC | FreeBASIC |
Open Cons For Output As #1
' Open Cons abre los flujos de entrada (stdin) o salida (stdout) estándar
' de la consola para leer o escribir.
If Err > 0 Then
Print #1, "stdout is not a tty."
Else
Print #1, "stdout is a tty."
End If
Close #1
Sleep
| Give a code snippet in #FreeBASIC
Task
Demonstrate how to check whether the output device is a terminal or not.
Related task
Check input device is a terminal
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sieve_of_Eratosthenes | Sieve of Eratosthenes | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
The Sieve of Eratosthenes is a simple algorithm that finds the prime numbers up to a given integer.
Task
Implement the Sieve of Eratosthenes algorithm, with the only allowed... | #ALGOL_68 | ALGOL 68 | BOOL prime = TRUE, non prime = FALSE;
PROC eratosthenes = (INT n)[]BOOL:
(
[n]BOOL sieve;
FOR i TO UPB sieve DO sieve[i] := prime OD;
INT m = ENTIER sqrt(n);
sieve[1] := non prime;
FOR i FROM 2 TO m DO
IF sieve[i] = prime THEN
FOR j FROM i*i BY i TO n DO
sieve[j] := non prime
OD
FI... | Give a code snippet in #ALGOL_68
This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
The Sieve of Eratosthenes is a simple algorithm that finds the prime numbers up to a given integer.
Task
Implement the Sieve of Eratosthenes ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dining_philosophers | Dining philosophers | The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. It is a modification of a problem posed by Edsger Dijkstra.
Five philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eating spaghetti. They eat at a rou... | #Phix | Phix | without js -- threads
integer fork1 = init_cs(),
fork2 = init_cs(),
fork3 = init_cs(),
fork4 = init_cs(),
fork5 = init_cs()
integer terminate = 0 -- control flag
procedure person(sequence name, atom left_fork, atom right_fork)
-- (except Russell, who gets left and rig... | Give a code snippet in #Phix
The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. It is a modification of a problem posed by Edsger Dijkstra.
Five philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eatin... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mutual_recursion | Mutual recursion | Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
)
=
n
−
M
(
F
(
n
−
1
)
)
,
... | #AWK | AWK | cat mutual_recursion.awk:
#!/usr/local/bin/gawk -f
# User defined functions
function F(n)
{ return n == 0 ? 1 : n - M(F(n-1)) }
function M(n)
{ return n == 0 ? 0 : n - F(M(n-1)) }
BEGIN {
for(i=0; i <= 20; i++) {
printf "%3d ", F(i)
}
print ""
for(i=0; i <= 20; i++) {
printf "%3d ", M(i)
}
pri... | Give a code snippet in #AWK
Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
)
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/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
| #Julia | Julia | run(`ls`) | Give a code snippet in #Julia
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/Sum_multiples_of_3_and_5 | Sum multiples of 3 and 5 | Task
The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.
Show output for n = 1000.
This is is the same as Project Euler problem 1.
Extra credit: do this efficiently for n = 1e20 or higher.
| #Maple | Maple |
F := unapply( sum(3*i,i=1..floor((n-1)/3))
+ sum(5*i,i=1..floor((n-1)/5))
- sum(15*i,i=1..floor((n-1)/15)), n);
F(1000);
F(10^20);
| Give a code snippet in #Maple
Task
The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.
Show output for n = 1000.
This is is the same as Project Euler problem 1.
Extra credit: do this efficiently for n = 1e20 or higher.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/HTTPS | HTTPS | Task
Send a GET request to obtain the resource located at the URL "https://www.w3.org/", then print it to the console.
Checking the host certificate for validity is recommended.
Do not authenticate. That is the subject of other tasks.
Readers may wish to contrast with the HTTP Request task, and also the task on HTT... | #Sidef | Sidef | var lwp = require('LWP::UserAgent'); # LWP::Protocol::https is needed
var url = 'https://rosettacode.org';
var ua = lwp.new(
agent => 'Mozilla/5.0',
ssl_opts => Hash.new(verify_hostname => 1),
);
var resp = ua.get(url);
resp.is_success || die "Failed to GET #{url.dump}: #{resp.status_line}";
print res... | Give a code snippet in #Sidef
Task
Send a GET request to obtain the resource located at the URL "https://www.w3.org/", then print it to the console.
Checking the host certificate for validity is recommended.
Do not authenticate. That is the subject of other tasks.
Readers may wish to contrast with the HTTP Request... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Man_or_boy_test | Man or boy test | Man or boy test
You are encouraged to solve this task according to the task description, using any language you may know.
Background: The man or boy test was proposed by computer scientist Donald Knuth as a means of evaluating implementations of the ALGOL 60 programming language. The aim of the test was to distinguis... | #Dylan | Dylan | define method a
(k :: <integer>, x1 :: <function>, x2 :: <function>, x3 :: <function>,
x4 :: <function>, x5 :: <function>)
=> (i :: <integer>)
local b() => (i :: <integer>)
k := k - 1;
a(k, b, x1, x2, x3, x4)
end;
if (k <= 0) x4() + x5() else b() end if
end method a;
defi... | Give a code snippet in #Dylan
Man or boy test
You are encouraged to solve this task according to the task description, using any language you may know.
Background: The man or boy test was proposed by computer scientist Donald Knuth as a means of evaluating implementations of the ALGOL 60 programming language. The ai... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Queue/Usage | Queue/Usage |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Ope... | #Perl | Perl | @queue = (); # we will simulate a queue in a array
push @queue, (1..5); # enqueue numbers from 1 to 5
print shift @queue,"\n"; # dequeue
print "array is empty\n" unless @queue; # is empty ?
print $n while($n = shift @queue); # dequeue all
print "\n";
print "array is empty\n" unless @queue; # is empty ? | Give a code snippet in #Perl
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sailors,_coconuts_and_a_monkey_problem | Sailors, coconuts and a monkey problem | Five sailors are shipwrecked on an island and collect a large pile of coconuts during the day.
That night the first sailor wakes up and decides to take his first share early so tries to divide the pile of coconuts equally into five piles but finds that there is one coconut left over, so he tosses it to a monkey and th... | #Scala | Scala | object Sailors extends App {
var x = 0
private def valid(n: Int, _nuts: Int): Boolean = {
var nuts = _nuts
for (k <- n until 0 by -1) {
if (nuts % n != 1) return false
nuts -= 1 + nuts / n
}
nuts != 0 && (nuts % n == 0)
}
for (nSailors <- 2 until 10) {
while (!valid(nSailors,... | Give a code snippet in #Scala
Five sailors are shipwrecked on an island and collect a large pile of coconuts during the day.
That night the first sailor wakes up and decides to take his first share early so tries to divide the pile of coconuts equally into five piles but finds that there is one coconut left over, so ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_an_array_of_composite_structures | Sort an array of composite structures |
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
... | #Common_Lisp | Common Lisp | CL-USER> (defparameter *test-scores* '(("texas" 68.9) ("ohio" 87.8) ("california" 76.2) ("new york" 88.2)) )
*TEST-SCORES* | Give a code snippet in #Common_Lisp
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 |
Qu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_multiples_of_3_and_5 | Sum multiples of 3 and 5 | Task
The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.
Show output for n = 1000.
This is is the same as Project Euler problem 1.
Extra credit: do this efficiently for n = 1e20 or higher.
| #Factor | Factor | USING: kernel math prettyprint ;
: sum-multiples ( m n upto -- sum )
>integer 1 - [ 2dup * ] dip
[ 2dup swap [ mod - + ] [ /i * 2/ ] 2bi ] curry tri@
[ + ] [ - ] bi* ;
3 5 1000 sum-multiples .
3 5 1e20 sum-multiples . | Give a code snippet in #Factor
Task
The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.
Show output for n = 1000.
This is is the same as Project Euler problem 1.
Extra credit: do this efficiently for n = 1e20 or higher.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Primality_by_Wilson%27s_theorem | Primality by Wilson's theorem | Task
Write a boolean function that tells whether a given integer is prime using Wilson's theorem.
By Wilson's theorem, a number p is prime if and only if p divides (p - 1)! + 1.
Remember that 1 and all non-positive integers are not prime.
See also
Cut-the-knot: Wilson's theorem.
Wikipedia: Wilson's theorem
| #Nim | Nim | import strutils, sugar
proc facmod(n, m: int): int =
## Compute (n - 1)! mod m.
result = 1
for k in 2..n:
result = (result * k) mod m
func isPrime(n: int): bool = (facmod(n - 1, n) + 1) mod n == 0
let primes = collect(newSeq):
for n in 2..100:
if n.isPrime: n
echo "Prim... | Give a code snippet in #Nim
Task
Write a boolean function that tells whether a given integer is prime using Wilson's theorem.
By Wilson's theorem, a number p is prime if and only if p divides (p - 1)! + 1.
Remember that 1 and all non-positive integers are not prime.
See also
Cut-the-knot: Wilson's theorem.
Wi... | 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 ... | #Slate | Slate | define: #multiply -> [| :a :b | a * b]. | Give a code snippet in #Slate
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/CUSIP | CUSIP |
This page uses content from Wikipedia. The original article was at CUSIP. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
A CUSIP is a nine-character alphanumeric code that identifies a North A... | #Visual_Basic_.NET | Visual Basic .NET | Module Module1
Function IsCUSIP(s As String) As Boolean
If s.Length <> 9 Then
Return False
End If
Dim sum = 0
For i = 0 To 7
Dim c = s(i)
Dim v As Integer
If "0" <= c AndAlso c <= "9" Then
v = Asc(c) - 48
... | Give a code snippet in #Visual_Basic_.NET
This page uses content from Wikipedia. The original article was at CUSIP. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
A CUSIP is a nine-character ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Doubly-linked_list/Element_definition | Doubly-linked list/Element definition | Task
Define the data structure for a doubly-linked list element.
The element should include a data member to hold its value and pointers to both the next element in the list and the previous element in the list.
The pointers should be mutable.
See also
Array
Associative array: Creation, Iteration
Collections
... | #Axe | Axe | Lbl LINK
r₂→{r₁}ʳ
0→{r₁+2}ʳ
0→{r₁+4}ʳ
r₁
Return
Lbl NEXT
{r₁+2}ʳ
Return
Lbl PREV
{r₁+4}ʳ
Return
Lbl VALUE
{r₁}ʳ
Return | Give a code snippet in #Axe
Task
Define the data structure for a doubly-linked list element.
The element should include a data member to hold its value and pointers to both the next element in the list and the previous element in the list.
The pointers should be mutable.
See also
Array
Associative array: Crea... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_length | String length | Task
Find the character and byte length of a string.
This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters.
By character, we mean an individual Unicode code point, not a user-visible grapheme containing combining characters.
F... | #C | C | #include <string.h>
int main(void)
{
const char *string = "Hello, world!";
size_t length = strlen(string);
return 0;
} | Give a code snippet in #C
Task
Find the character and byte length of a string.
This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters.
By character, we mean an individual Unicode code point, not a user-visible grapheme containi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Yabasic | Yabasic |
error "Goodbye World!"
| Give a code snippet in #Yabasic
Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard ou... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix-exponentiation_operator | Matrix-exponentiation operator | Most programming languages have a built-in implementation of exponentiation for integers and reals only.
Task
Demonstrate how to implement matrix exponentiation as an operator.
| #Octave | Octave | M = [ 3, 2; 2, 1 ];
M^0
M^1
M^2
M^(-1)
M^0.5 | Give a code snippet in #Octave
Most programming languages have a built-in implementation of exponentiation for integers and reals only.
Task
Demonstrate how to implement matrix exponentiation as an operator.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
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 |... | #Clojure | Clojure | (let [[a b] (repeatedly read)]
(doseq [[op string] [[< "less than"]
[> "greater than"]
[= "equal to"]]]
(when (op a b)
(println (str a " is " string " " b))))) | Give a code snippet in #Clojure
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operation... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/code_generator | Compiler/code generator | A code generator translates the output of the syntax analyzer and/or semantic analyzer
into lower level code, either assembly, object, or virtual.
Task[edit]
Take the output of the Syntax analyzer task - which is a flattened Abstract Syntax Tree (AST) - and convert it to virtual machine code, that can be run by the
Vi... | #Go | Go | package main
import (
"bufio"
"encoding/binary"
"fmt"
"log"
"os"
"strconv"
"strings"
)
type NodeType int
const (
ndIdent NodeType = iota
ndString
ndInteger
ndSequence
ndIf
ndPrtc
ndPrts
ndPrti
ndWhile
ndAssign
ndNegate
ndNot
ndMul
... | Give a code snippet in #Go
A code generator translates the output of the syntax analyzer and/or semantic analyzer
into lower level code, either assembly, object, or virtual.
Task[edit]
Take the output of the Syntax analyzer task - which is a flattened Abstract Syntax Tree (AST) - and convert it to virtual machine cod... | 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... | #AutoHotkey | AutoHotkey | Cset(C,1,1)
MsgBox % Cstr(C) ; 1 + i*1
Cneg(C,C)
MsgBox % Cstr(C) ; -1 - i*1
Cadd(C,C,C)
MsgBox % Cstr(C) ; -2 - i*2
Cinv(D,C)
MsgBox % Cstr(D) ; -0.25 + 0.25*i
Cmul(C,C,D)
MsgBox % Cstr(C) ; 1 + i*0
Cset(ByRef C, re, im) {
VarSetCapacity(C,16)
NumPut(re,C,0,"double")
NumPut(im,C,8,"double")
}
Cre(ByRef... | Give a code snippet in #AutoHotkey
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
{\disp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Naming_conventions | Naming conventions | Many languages have naming conventions regarding the identifiers used in the language, its libraries, and programs written in the language. Such conventions, which may be classified as de facto or de jure depending on how they are enforced,
often take the form of rules regarding prefixes, suffixes, and the use of upper... | #M2000_Interpreter | M2000 Interpreter |
Class Alfa$ {
Private:
myValue$
Public:
Set {
Read .myValue$
}
Value {
=.myValue$
}
Module Doit {
Function TwoChars$(A$) {
=Left$(Left$(a$,1)+Right$(a$,1)+"??",2)
... | Give a code snippet in #M2000_Interpreter
Many languages have naming conventions regarding the identifiers used in the language, its libraries, and programs written in the language. Such conventions, which may be classified as de facto or de jure depending on how they are enforced,
often take the form of rules regardi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rosetta_Code/Count_examples | Rosetta Code/Count examples | task
Essentially, count the number of occurrences of =={{header| on each task page.
Output:
100 doors: 20 examples.
99 Bottles of Beer: 29 examples.
Abstract type: 10 examples.
Total: X examples.
For a full output, updated periodically, see Rosetta Code/Count examples/Full list.
You'll need to use the Media Wiki AP... | #PureBasic | PureBasic | Procedure handleError(value, msg.s)
If value = 0
MessageRequester("Error", msg)
End
EndIf
EndProcedure
handleError(InitNetwork(), "Unable to initialize network functions.")
If OpenConsole()
Define url$, x1$, y1$, title$, unescapedTitle$, encodedURL$
Define x2, i, j, totalExamples, totalTasks
url$ = ... | Give a code snippet in #PureBasic
task
Essentially, count the number of occurrences of =={{header| on each task page.
Output:
100 doors: 20 examples.
99 Bottles of Beer: 29 examples.
Abstract type: 10 examples.
Total: X examples.
For a full output, updated periodically, see Rosetta Code/Count examples/Full list.
Y... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Heronian_triangles | Heronian triangles | Hero's formula for the area of a triangle given the length of its three sides a, b, and c is given by:
A
=
s
(
s
−
a
)
(
s
−
b
)
(
s
−
c
)
,
{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}},}
where s is half the perimeter of the triangle; that is,
s
=
a
+
b
+
c
2
.
{\displaystyle s... | #ALGOL_W | ALGOL W | begin
% record to hold details of a Heronian triangle %
record Heronian ( integer a, b, c, area, perimeter );
% returns the details of the Heronian Triangle with sides a, b, c or nil if it isn't one %
reference(Heronian) procedure tryHt( integer value a, b, c ) ;
begin
real s,... | Give a code snippet in #ALGOL_W
Hero's formula for the area of a triangle given the length of its three sides a, b, and c is given by:
A
=
s
(
s
−
a
)
(
s
−
b
)
(
s
−
c
)
,
{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}},}
where s is half the perimeter of the triangle; that is,
s
=
a
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Levenshtein_distance/Alignment | Levenshtein distance/Alignment | The Levenshtein distance algorithm returns the number of atomic operations (insertion, deletion or edition) that must be performed on a string in order to obtain an other one, but it does not say anything about the actual operations used or their order.
An alignment is a notation used to describe the operations used t... | #Raku | Raku | sub align ( Str $σ, Str $t ) {
my @s = flat *, $σ.comb;
my @t = flat *, $t.comb;
my @A;
@A[$_][ 0]<d s t> = $_, @s[1..$_].join, '-' x $_ for ^@s;
@A[ 0][$_]<d s t> = $_, '-' x $_, @t[1..$_].join for ^@t;
for 1 ..^ @s X 1..^ @t -> (\i, \j) {
if @s[i] ne @t[j] {
@A[i][j]<d> = 1 + my $min... | Give a code snippet in #Raku
The Levenshtein distance algorithm returns the number of atomic operations (insertion, deletion or edition) that must be performed on a string in order to obtain an other one, but it does not say anything about the actual operations used or their order.
An alignment is a notation used to ... | 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
... | #Maple | Maple | M:=<<3|2+I>,<2-I|1>>:
with(LinearAlgebra):
IsNormal:=A->EqualEntries(A^%H.A,A.A^%H):
M^%H;
HermitianTranspose(M);
type(M,'Matrix'(hermitian));
IsNormal(M);
IsUnitary(M); | Give a code snippet in #Maple
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}
.
(
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stack | Stack |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack is accessed through its top.
The ba... | #UNIX_Shell | UNIX Shell | init() {
if [[ -n $KSH_VERSION ]]; then
set -A stack
else
stack=(); # this sets stack to '()' in ksh
fi
}
push() {
stack=("$1" "${stack[@]}")
}
stack_top() {
# this approach sidesteps zsh indexing difference
set -- "${stack[@]}"
printf '%s\n' "$1"
}
pop() {
stack_top
stack=("${stack[@]:... | Give a code snippet in #UNIX_Shell
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Secure_temporary_file | Secure temporary file | Task
Create a temporary file, securely and exclusively (opening it such that there are no possible race conditions).
It's fine assuming local filesystem semantics (NFS or other networking filesystems can have signficantly more complicated semantics for satisfying the "no race conditions" criteria).
The function shou... | #Clojure | Clojure | (let [temp-file (java.io.File/createTempFile "pre" ".suff")]
; insert logic here that would use temp-file
(.delete temp-file)) | Give a code snippet in #Clojure
Task
Create a temporary file, securely and exclusively (opening it such that there are no possible race conditions).
It's fine assuming local filesystem semantics (NFS or other networking filesystems can have signficantly more complicated semantics for satisfying the "no race conditio... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Add_a_variable_to_a_class_instance_at_runtime | Add a variable to a class instance at runtime | Demonstrate how to dynamically add variables to an object (a class instance) at runtime.
This is useful when the methods/variables of an instance are based on a data file that isn't available until runtime. Hal Fulton gives an example of creating an OO CSV parser at An Exercise in Metaprogramming with Ruby. This is re... | #JavaScript | JavaScript | e = {} // generic object
e.foo = 1
e["bar"] = 2 // name specified at runtime | Give a code snippet in #JavaScript
Demonstrate how to dynamically add variables to an object (a class instance) at runtime.
This is useful when the methods/variables of an instance are based on a data file that isn't available until runtime. Hal Fulton gives an example of creating an OO CSV parser at An Exercise in M... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Horizontal_sundial_calculations | Horizontal sundial calculations | Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Island, aka Ernest Legouve Reef), wit... | #ALGOL_68 | ALGOL 68 | BEGIN
REAL lat, slat, lng, ref;
print ( "Enter latitude => " ); read (lat);
print ( "Enter longitude => " ); read (lng);
print ( "Enter legal meridian => " ); read (ref);
new line(stand out);
slat := sin(lat*2*pi/360) ;
print ( (" sine of latitude: ", float(slat,8,2,1), new line ) );
p... | Give a code snippet in #ALGOL_68
Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Isl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anti-primes | Anti-primes | The anti-primes
(or highly composite numbers, sequence A002182 in the OEIS)
are the natural numbers with more factors than any smaller than itself.
Task
Generate and show here, the first twenty anti-primes.
Related tasks
Factors of an integer
Sieve of Eratosthenes
| #Maple | Maple | antiprimes := proc(n)
local ap, i, max_divisors, num_divisors;
max_divisors := 0;
ap := [];
for i from 1 while numelems(ap) < n do
num_divisors := numelems(NumberTheory:-Divisors(i));
if num_divisors > max_divisors then
ap := [op(ap), i];
max_divisors := num_divisors;
end if;
end do;
retur... | Give a code snippet in #Maple
The anti-primes
(or highly composite numbers, sequence A002182 in the OEIS)
are the natural numbers with more factors than any smaller than itself.
Task
Generate and show here, the first twenty anti-primes.
Related tasks
Factors of an integer
Sieve of Eratosthenes
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Equal_prime_and_composite_sums | Equal prime and composite sums | Suppose we have a sequence of prime sums, where each term Pn is the sum of the first n primes.
P = (2), (2 + 3), (2 + 3 + 5), (2 + 3 + 5 + 7), (2 + 3 + 5 + 7 + 11), ...
P = 2, 5, 10, 17, 28, etc.
Further; suppose we have a sequence of composite sums, where each term Cm is the sum of the first m composites.
C = (4... | #Julia | Julia | using Primes
function getsequencematches(N, masksize = 1_000_000_000)
pmask = primesmask(masksize)
found, psum, csum, pindex, cindex, pcount, ccount = 0, 2, 4, 2, 4, 1, 1
incrementpsum() = (pindex += 1; if pmask[pindex] psum += pindex; pcount += 1 end)
incrementcsum() = (cindex += 1; if !pmask[cindex]... | Give a code snippet in #Julia
Suppose we have a sequence of prime sums, where each term Pn is the sum of the first n primes.
P = (2), (2 + 3), (2 + 3 + 5), (2 + 3 + 5 + 7), (2 + 3 + 5 + 7 + 11), ...
P = 2, 5, 10, 17, 28, etc.
Further; suppose we have a sequence of composite sums, where each term Cm is the sum of ... | 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 ... | #EchoLisp | EchoLisp |
(define-syntax-rule (deg->radian deg) (* deg 1/180 PI))
(define-syntax-rule (radian->deg rad) (* 180 (/ PI) rad))
(define (mean-angles angles)
(radian->deg
(angle
(for/sum ((a angles)) (make-polar 1 (deg->radian a))))))
(mean-angles '( 350 10))
→ -0
(mean-angles '[90 180 270 360])
→ -9... | Give a code snippet in #EchoLisp
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 r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Permutation_test | Permutation test | Permutation test
You are encouraged to solve this task according to the task description, using any language you may know.
A new medical treatment was tested on a population of
n
+
m
{\displaystyle n+m}
volunteers, with each volunteer randomly assigned either to a group of
n
{\displaystyle n}
treatment... | #Python | Python | from itertools import combinations as comb
def statistic(ab, a):
sumab, suma = sum(ab), sum(a)
return ( suma / len(a) -
(sumab -suma) / (len(ab) - len(a)) )
def permutationTest(a, b):
ab = a + b
Tobs = statistic(ab, a)
under = 0
for count, perm in enumerate(comb(ab, len(a)), 1):... | Give a code snippet in #Python
Permutation test
You are encouraged to solve this task according to the task description, using any language you may know.
A new medical treatment was tested on a population of
n
+
m
{\displaystyle n+m}
volunteers, with each volunteer randomly assigned either to a group of
n... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Palindrome_detection | Palindrome detection | A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as a wrapper to the first) which ... | #Dart | Dart |
bool isPalindrome(String s){
for(int i = 0; i < s.length/2;i++){
if(s[i] != s[(s.length-1) -i])
return false;
}
return true;
}
| Give a code snippet in #Dart
A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as ... | 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... | #Whenever | Whenever |
1 2#read()-N(2);
2 2;
3 defer(1 || N(2) > 90 || N(2) < 65) 5#65-N(5);
4 defer(1 || N(2) > 122 || N(2) < 97) 5#97-N(5);
5 5;
6 defer(3 && 4) put(U(((N(2) - N(5) + 13) % 26) + N(5)));
7 defer(1 || N(2) > 64 || N(2) == 0) put(U(N(2)));
8 again(8) defer(6 && 7) 1,-6#N(6)-1,-7#N(7)-1,-3#N(3)-1,-4#N(4)-1;
9 defer(1 || N(2)... | Give a code snippet in #Whenever
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/9_billion_names_of_God_the_integer | 9 billion names of God the integer | This task is a variation of the short story by Arthur C. Clarke.
(Solvers should be aware of the consequences of completing this task.)
In detail, to specify what is meant by a “name”:
The integer 1 has 1 name “1”.
The integer 2 has 2 names “1+1”, and “2”.
The integer 3 has 3 names “1+1+1”, “2+1”, ... | #Swift | Swift | var cache = [[1]]
func namesOfGod(n:Int) -> [Int] {
for l in cache.count...n {
var r = [0]
for x in 1...l {
r.append(r[r.count - 1] + cache[l - x][min(x, l-x)])
}
cache.append(r)
}
return cache[n]
}
func row(n:Int) -> [Int] {
let r = namesOfGod(n)
var re... | Give a code snippet in #Swift
This task is a variation of the short story by Arthur C. Clarke.
(Solvers should be aware of the consequences of completing this task.)
In detail, to specify what is meant by a “name”:
The integer 1 has 1 name “1”.
The integer 2 has 2 names “1+1”, and “2”.
The integer 3 has... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Execute_Computer/Zero | Execute Computer/Zero | Execute Computer/Zero is an implementation of Computer/zero Assembly.
Other implementations of Computer/zero Assembly.
Task
Create a Computer/zero Assembly emulator. You may consider this webpage as a reference implementation. Output the results of the sample programs "2+2" and "7*8" found there.
The virtual machi... | #Phix | Phix | with javascript_semantics
constant NOP = 0b000_00000, -- no operation
LDA = 0b001_00000, -- load accumulator, a := memory [xxxxx]
STA = 0b010_00000, -- store accumulator, memory [xxxxx] := a
ADD = 0b011_00000, -- add, a := a + memory [xxxxx]
SUB = 0b100_00000, -- subtract, a := a – m... | Give a code snippet in #Phix
Execute Computer/Zero is an implementation of Computer/zero Assembly.
Other implementations of Computer/zero Assembly.
Task
Create a Computer/zero Assembly emulator. You may consider this webpage as a reference implementation. Output the results of the sample programs "2+2" and "7*8" foun... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stable_marriage_problem | Stable marriage problem | Solve the Stable marriage problem using the Gale/Shapley algorithm.
Problem description
Given an equal number of men and women to be paired for marriage, each man ranks all the women in order of his preference and each woman ranks all the men in order of her preference.
A stable set of engagements for marriage is o... | #Julia | Julia |
# This is not optimized, but tries to follow the pseudocode given the Wikipedia entry below.
# Reference: https://en.wikipedia.org/wiki/Stable_marriage_problem#Algorithm
const males = ["abe", "bob", "col", "dan", "ed", "fred", "gav", "hal", "ian", "jon"]
const females = ["abi", "bea", "cath", "dee", "eve", "fay", "... | Give a code snippet in #Julia
Solve the Stable marriage problem using the Gale/Shapley algorithm.
Problem description
Given an equal number of men and women to be paired for marriage, each man ranks all the women in order of his preference and each woman ranks all the men in order of her preference.
A stable set o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Lah_numbers | Lah numbers | Lah numbers, sometimes referred to as Stirling numbers of the third kind, are coefficients of polynomial expansions expressing rising factorials in terms of falling factorials.
Unsigned Lah numbers count the number of ways a set of n elements can be partitioned into k non-empty linearly ordered subsets.
Lah numbers a... | #F.C5.8Drmul.C3.A6 | Fōrmulæ | package main
import (
"fmt"
"math/big"
)
func main() {
limit := 100
last := 12
unsigned := true
l := make([][]*big.Int, limit+1)
for n := 0; n <= limit; n++ {
l[n] = make([]*big.Int, limit+1)
for k := 0; k <= limit; k++ {
l[n][k] = new(big.Int)
}
... | Give a code snippet in #F.C5.8Drmul.C3.A6
Lah numbers, sometimes referred to as Stirling numbers of the third kind, are coefficients of polynomial expansions expressing rising factorials in terms of falling factorials.
Unsigned Lah numbers count the number of ways a set of n elements can be partitioned into k non-emp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fivenum | Fivenum | Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, the R programming language i... | #Visual_Basic_.NET | Visual Basic .NET | Imports System.Runtime.CompilerServices
Imports System.Text
Module Module1
<Extension()>
Function AsString(Of T)(c As ICollection(Of T), Optional format As String = "{0}") As String
Dim sb As New StringBuilder("[")
Dim it = c.GetEnumerator()
If it.MoveNext() Then
sb.Appen... | Give a code snippet in #Visual_Basic_.NET
Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
Fo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Genie | Genie | [indent=4]
/*
Command line arguments, in Genie
valac commandLine.gs
./commandLine sample arguments 'four in total here, including args 0'
*/
init
// Output the number of arguments
print "%d command line argument(s):", args.length
// Enumerate all command line arguments
for s in args
... | Give a code snippet in #Genie
Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Active_object | Active object | In object-oriented programming an object is active when its state depends on clock. Usually an active object encapsulates a task that updates the object's state. To the outer world the object looks like a normal object with methods that can be called from outside. Implementation of such methods must have a certain sync... | #Wren | Wren | import "scheduler" for Scheduler
import "timer" for Timer
var Interval = 0
class Integrator {
construct new() {
_sum = 0
}
input(k) {
_k = k
_v0 = k.call(0)
_t = 0
_running = true
integrate_()
}
output { _sum }
stop() {
_running =... | Give a code snippet in #Wren
In object-oriented programming an object is active when its state depends on clock. Usually an active object encapsulates a task that updates the object's state. To the outer world the object looks like a normal object with methods that can be called from outside. Implementation of such me... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rock-paper-scissors | Rock-paper-scissors | Task
Implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI (artificial intelligence) player.
Rock Paper Scissors is a two player game.
Each player chooses one of rock, paper or scissors, without knowing the other player's choice.
The winner is decided by a set of rules:
... | #Rust | Rust | extern crate rand;
#[macro_use]
extern crate rand_derive;
use std::io;
use rand::Rng;
use Choice::*;
#[derive(PartialEq, Clone, Copy, Rand, Debug)]
enum Choice {
Rock,
Paper,
Scissors,
}
fn beats(c1: Choice, c2: Choice) -> bool {
(c1 == Rock && c2 == Scissors) || (c1 == Scissors && c2 == Paper) ||... | Give a code snippet in #Rust
Task
Implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI (artificial intelligence) player.
Rock Paper Scissors is a two player game.
Each player chooses one of rock, paper or scissors, without knowing the other player's choice.
The winner ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #Seed7 | Seed7 | odd(aNumber) | Give a code snippet in #Seed7
Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Short-circuit_evaluation | Short-circuit evaluation | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Assume functions a and b return boolean values, and further, the execution of function b takes considerable resources without side effects, an... | #Visual_Basic_.NET | Visual Basic .NET | Module Module1
Function A(v As Boolean) As Boolean
Console.WriteLine("a")
Return v
End Function
Function B(v As Boolean) As Boolean
Console.WriteLine("b")
Return v
End Function
Sub Test(i As Boolean, j As Boolean)
Console.WriteLine("{0} and {1} = {2} (ea... | Give a code snippet in #Visual_Basic_.NET
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Assume functions a and b return boolean values, and further, the execution of function b takes cons... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Towers_of_Hanoi | Towers of Hanoi | Task
Solve the Towers of Hanoi problem with recursion.
| #R | R | hanoimove <- function(ndisks, from, to, via) {
if (ndisks == 1) {
cat("move disk from", from, "to", to, "\n")
} else {
hanoimove(ndisks - 1, from, via, to)
hanoimove(1, from, to, via)
hanoimove(ndisks - 1, via, to, from)
}
}
hanoimove(4, 1, 2, 3) | Give a code snippet in #R
Task
Solve the Towers of Hanoi problem with recursion.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Flow-control_structures | Flow-control structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Struc... | #Ring | Ring |
i = 1
while true
see i + nl
if i = 10 see "Break!" exit ok
i = i + 1
end
| Give a code snippet in #Ring
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Monty_Hall_problem | Monty Hall problem |
Suppose you're on a game show and you're given the choice of three doors.
Behind one door is a car; behind the others, goats.
The car and the goats were placed randomly behind the doors before the show.
Rules of the game
After you have chosen a door, the door remains closed for the time being.
The game show hos... | #PowerShell | PowerShell | #Declaring variables
$intIterations = 10000
$intKept = 0
$intSwitched = 0
#Creating a function
Function Play-MontyHall()
{
#Using a .NET object for randomization
$objRandom = New-Object -TypeName System.Random
#Generating the winning door number
$intWin = $objRandom.Next(1,4)
#Generating t... | Give a code snippet in #PowerShell
Suppose you're on a game show and you're given the choice of three doors.
Behind one door is a car; behind the others, goats.
The car and the goats were placed randomly behind the doors before the show.
Rules of the game
After you have chosen a door, the door remains closed fo... | 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) ... | #Gambas | Gambas | 'Altered to prevent lines starting with ']' or ending with '[' being generated as they can't work
siNumberOfBrackets As Short = 20 'Maximum amount of brackets in a line
siNumberOfLines As Short = 20 'Amount of lines to test
'----
Public Sub Main()
Dim sBrks As String[] = GenerateBrack... | Give a code snippet in #Gambas
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/Sum_of_squares | Sum of squares | Task
Write a program to find the sum of squares of a numeric vector.
The program should work on a zero-length vector (with an answer of 0).
Related task
Mean
| #Smalltalk | Smalltalk | #(3 1 4 1 5 9) inject: 0 into: [:sum :aNumber | sum + aNumber squared] | Give a code snippet in #Smalltalk
Task
Write a program to find the sum of squares of a numeric vector.
The program should work on a zero-length vector (with an answer of 0).
Related task
Mean
| 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... | #Scala | Scala | scala> def if2[A](x: => Boolean)(y: => Boolean)(xyt: => A) = new {
| def else1(xt: => A) = new {
| def else2(yt: => A) = new {
| def orElse(nt: => A) = {
| if(x) {
| if(y) xyt else xt
| } else if(y) {
| yt
| } else {
| ... | Give a code snippet in #Scala
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.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dynamic_variable_names | Dynamic variable names | Task
Create a variable with a user-defined name.
The variable name should not be written in the program text, but should be taken from the user dynamically.
See also
Eval in environment is a similar task.
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | varname = InputString["Enter a variable name"];
varvalue = InputString["Enter a value"];
ReleaseHold[ Hold[Set["nameholder", "value"]] /. {"nameholder" -> Symbol[varname], "value" -> varvalue}];
Print[varname, " is now set to ", Symbol[varname]] | Give a code snippet in #Mathematica_.2F_Wolfram_Language
Task
Create a variable with a user-defined name.
The variable name should not be written in the program text, but should be taken from the user dynamically.
See also
Eval in environment is a similar task.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Singleton | Singleton | A Global Singleton is a class of which only one instance exists within a program.
Any attempt to use non-static members of the class involves performing operations on this one instance.
| #JavaScript | JavaScript | function Singleton() {
if(Singleton._instance) return Singleton._instance;
this.set("");
Singleton._instance = this;
}
Singleton.prototype.set = function(msg) { this.msg = msg; }
Singleton.prototype.append = function(msg) { this.msg += msg; }
Singleton.prototype.get = function() { return this.msg; }
var a = ne... | Give a code snippet in #JavaScript
A Global Singleton is a class of which only one instance exists within a program.
Any attempt to use non-static members of the class involves performing operations on this one instance.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
W... | #AWK | AWK | BEGIN {
a = "a string"
b = a
sub(/a/, "X", a) # modify a
print b # b is a copy, not a reference to...
} | Give a code snippet in #AWK
This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty str... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Make_directory_path | Make directory path | Task
Create a directory and any missing parents.
This task is named after the posix mkdir -p command, and several libraries which implement the same behavior.
Please implement a function of a single path string (for example ./path/to/dir) which has the above side-effect.
If the directory already exists, return succe... | #11l | 11l | fs:create_dirs(path) | Give a code snippet in #11l
Task
Create a directory and any missing parents.
This task is named after the posix mkdir -p command, and several libraries which implement the same behavior.
Please implement a function of a single path string (for example ./path/to/dir) which has the above side-effect.
If the directory... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Set_of_real_numbers | Set of real numbers | All real numbers form the uncountable set ℝ. Among its subsets, relatively simple are the convex sets, each expressed as a range between two real numbers a and b where a ≤ b. There are actually four cases for the meaning of "between", depending on open or closed boundary:
[a, b]: {x | a ≤ x and x ≤ b }
(a, b): {x | ... | #C | C | #include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
struct RealSet {
bool(*contains)(struct RealSet*, struct RealSet*, double);
struct RealSet *left;
struct RealSet *right;
double low, high;
};
typedef enum {
CLOSED,
LEFT_OPEN,
RIGHT_OPEN,
BOTH_OPEN,
} Range... | Give a code snippet in #C
All real numbers form the uncountable set ℝ. Among its subsets, relatively simple are the convex sets, each expressed as a range between two real numbers a and b where a ≤ b. There are actually four cases for the meaning of "between", depending on open or closed boundary:
[a, b]: {x | a ≤ x... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pierpont_primes | Pierpont primes | A Pierpont prime is a prime number of the form: 2u3v + 1 for some non-negative integers u and v .
A Pierpont prime of the second kind is a prime number of the form: 2u3v - 1 for some non-negative integers u and v .
The term "Pierpont primes" is generally understood to mean the first definition, but will be c... | #Go | Go | package main
import (
"fmt"
big "github.com/ncw/gmp"
"sort"
)
var (
one = new(big.Int).SetUint64(1)
two = new(big.Int).SetUint64(2)
three = new(big.Int).SetUint64(3)
)
func pierpont(ulim, vlim int, first bool) []*big.Int {
p := new(big.Int)
p2 := new(big.Int).Set(one)
p3 :=... | Give a code snippet in #Go
A Pierpont prime is a prime number of the form: 2u3v + 1 for some non-negative integers u and v .
A Pierpont prime of the second kind is a prime number of the form: 2u3v - 1 for some non-negative integers u and v .
The term "Pierpont primes" is generally understood to mean the fir... | 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.
... | #LiveCode | LiveCode | set the defaultFolder to the documents folder -- the documents folder is a "specialFolderPath"
put the files into docfiles
filter docfiles with "*.txt"
put docfiles | Give a code snippet in #LiveCode
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 director... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Top_rank_per_group | Top rank per group | Task
Find the top N salaries in each department, where N is provided as a parameter.
Use this data as a formatted internal data structure (adapt it to your language-native idioms, rather than parse at runtime), or identify your external data source:
Employee Name,Employee ID,Salary,Department
Tyler Bennett... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | InitialList ={{"Tyler Bennett","E10297",32000,"D101"},
{"John Rappl","E21437",47000,"D050"},{"George Woltman","E00127",53500,"D101"},
{"Adam Smith","E63535",18000,"D202"},{"Claire Buckman","E39876",27800,"D202"},
{"David McClellan","E04242",41500,"D101"},{"Rich Holcomb","E01234",49500,"D202"},
{"Nathan Adams","E41298",... | Give a code snippet in #Mathematica.2FWolfram_Language
Task
Find the top N salaries in each department, where N is provided as a parameter.
Use this data as a formatted internal data structure (adapt it to your language-native idioms, rather than parse at runtime), or identify your external data source:
E... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Determine_if_a_string_has_all_the_same_characters | Determine if a string has all the same characters | Task
Given a character string (which may be empty, or have a length of zero characters):
create a function/procedure/routine to:
determine if all the characters in the string are the same
indicate if or which character is different from the previous character
display each string and its length (as the... | #REXX | REXX | /*REXX program verifies that all characters in a string are all the same (character). */
@chr= ' [character' /* define a literal used for SAY.*/
@all= 'all the same character for string (length' /* " " " " " " */
@.= ... | Give a code snippet in #REXX
Task
Given a character string (which may be empty, or have a length of zero characters):
create a function/procedure/routine to:
determine if all the characters in the string are the same
indicate if or which character is different from the previous character
display each s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Nested | Loops/Nested | Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over
[
1
,
…
,
20
]
{\displaystyle [1,\ldots ,20]}
.
The loops iterate rows and columns of the array printing the elements until the value
20
{\displaystyle 20}
is met.
Specifically, this task als... | #Tcl | Tcl | set ary [subst [lrepeat 10 [lrepeat 5 {[expr int(rand()*20+1)]}]]]
try {
foreach row $ary {
foreach col $row {
puts -nonewline [format %3s $col]
if {$col == 20} {
throw MULTIBREAK "we're done"
}
}
puts ,
}
} trap MULTIBREAK {} {}
puts... | Give a code snippet in #Tcl
Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over
[
1
,
…
,
20
]
{\displaystyle [1,\ldots ,20]}
.
The loops iterate rows and columns of the array printing the elements until the value
20
{\displaystyle 20}
is met.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catalan_numbers | Catalan numbers | Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
for
n
≥
0.
{\displaystyle C... | #GAP | GAP | Catalan1 := n -> Binomial(2*n, n) - Binomial(2*n, n - 1);
Catalan2 := n -> Binomial(2*n, n)/(n + 1);
Catalan3 := function(n)
local k, c;
c := 1;
k := 0;
while k < n do
k := k + 1;
c := 2*(2*k - 1)*c/(k + 1);
od;
return c;
end;
Catalan4_memo := [1];
Catalan4 := function(n)
... | Give a code snippet in #GAP
Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
fo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anagrams/Deranged_anagrams | Anagrams/Deranged anagrams | Two or more words are said to be anagrams if they have the same characters, but in a different order.
By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words.
Task[edit]
Use the word list at uni... | #Perl | Perl | sub deranged { # only anagrams ever get here
my @a = split('', shift); # split word into letters
my @b = split('', shift);
for (0 .. $#a) {
$a[$_] eq $b[$_] and return;
}
return 1
}
sub find_deranged {
for my $i ( 0 ..... | Give a code snippet in #Perl
Two or more words are said to be anagrams if they have the same characters, but in a different order.
By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words.
Task[... | christopher/rosetta-code | |
http://rosettacode.org/wiki/99_bottles_of_beer | 99 bottles of beer | Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall
98 bottles of beer
Take one dow... | #Logtalk | Logtalk | :- object(bottles).
:- initialization(sing(99)).
sing(0) :-
write('No more bottles of beer on the wall, no more bottles of beer.'), nl,
write('Go to the store and buy some more, 99 bottles of beer on the wall.'), nl, nl.
sing(N) :-
N > 0,
N2 is N -1,
beers(N), wri... | Give a code snippet in #Logtalk
Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) sq... | #JAMES_II.2FRule-based_Cellular_Automata | JAMES II/Rule-based Cellular Automata | @caversion 1;
dimensions 2;
//using Moore neighborhood
neighborhood moore;
//available states
state DEAD, ALIVE;
/*
if current state is ALIVE and the
neighborhood does not contain 2 or
3 ALIVE states the cell changes to
DEAD
*/
rule{ALIVE}:!ALIVE{2,3}->DEAD;
/*
if current state is DEAD and there
are... | Give a code snippet in #JAMES_II.2FRule-based_Cellular_Automata
The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 w... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Balanced_ternary | Balanced ternary | Balanced ternary is a way of representing numbers. Unlike the prevailing binary representation, a balanced ternary integer is in base 3, and each digit can have the values 1, 0, or −1.
Examples
Decimal 11 = 32 + 31 − 30, thus it can be written as "++−"
Decimal 6 = 32 − 31 + 0 × 30, thus it can be written as "+−0"
... | #OCaml | OCaml | type btdigit = Pos | Zero | Neg
type btern = btdigit list
let to_string n =
String.concat ""
(List.rev_map (function Pos -> "+" | Zero -> "0" | Neg -> "-") n)
let from_string s =
let sl = ref [] in
let digit = function '+' -> Pos | '-' -> Neg | '0' -> Zero
| _ -> failwith "invalid digit" in
... | Give a code snippet in #OCaml
Balanced ternary is a way of representing numbers. Unlike the prevailing binary representation, a balanced ternary integer is in base 3, and each digit can have the values 1, 0, or −1.
Examples
Decimal 11 = 32 + 31 − 30, thus it can be written as "++−"
Decimal 6 = 32 − 31 + 0 × 30, t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Colour_bars/Display | Colour bars/Display | Task
Display a series of vertical color bars across the width of the display.
The color bars should either use:
the system palette, or
the sequence of colors:
black
red
green
blue
magenta
cyan
yellow
white
| #Ring | Ring |
load "guilib.ring"
new qapp
{
win1 = new qwidget() {
setwindowtitle("drawing using qpainter")
setwinicon(self,"C:\Ring\bin\image\browser.png")
setgeometry(100,100,500,600)
label1 = new qlabel(win1) {
setgeometry(10,... | Give a code snippet in #Ring
Task
Display a series of vertical color bars across the width of the display.
The color bars should either use:
the system palette, or
the sequence of colors:
black
red
green
blue
magenta
cyan
yellow
white
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Binary_search | Binary search | A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret number, and will only tell the p... | #Hoon | Hoon | |= [arr=(list @ud) x=@ud]
=/ lo=@ud 0
=/ hi=@ud (dec (lent arr))
|-
?> (lte lo hi)
=/ mid (div (add lo hi) 2)
=/ val (snag mid arr)
?: (lth x val) $(hi (dec mid))
?: (gth x val) $(lo +(mid))
mid | Give a code snippet in #Hoon
A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret nu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bin_given_limits | Bin given limits | You are given a list of n ascending, unique numbers which are to form limits
for n+1 bins which count how many of a large set of input numbers fall in the
range of each bin.
(Assuming zero-based indexing)
bin[0] counts how many inputs are < limit[0]
bin[1] counts how many inputs are >= limit[0] and < limit[1]
... | #REXX | REXX | /*REXX program counts how many numbers of a set that fall in the range of each bin. */
lims= 23 37 43 53 67 83 /* ◄■■■■■■1st set of bin limits & data.*/
data= 95 21 94 12 99 4 70 75 83 93 52 80 57 5 53 86 65 17 92 83 71 61 54 58 47 ,
16 8 9 32 84 7 87 46 19 30 37 96 6 98 40 79 97 45 ... | Give a code snippet in #REXX
You are given a list of n ascending, unique numbers which are to form limits
for n+1 bins which count how many of a large set of input numbers fall in the
range of each bin.
(Assuming zero-based indexing)
bin[0] counts how many inputs are < limit[0]
bin[1] counts how many inputs ar... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers | Luhn test of credit card numbers | The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits.
Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test:
Reverse the order of the digits in the number.
Tak... | #Ada | Ada | with Ada.Text_IO;
use Ada.Text_IO;
procedure Luhn is
function Luhn_Test (Number: String) return Boolean is
Sum : Natural := 0;
Odd : Boolean := True;
Digit: Natural range 0 .. 9;
begin
for p in reverse Number'Range loop
Digit := Integer'Value (Number (p..p));
if Odd then
S... | Give a code snippet in #Ada
The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits.
Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test:
Reverse the order of t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ternary_logic | Ternary logic |
This page uses content from Wikipedia. The original article was at Ternary logic. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In logic, a three-valued logic (also trivalent, ternary, or trinary... | #Icon_and_Unicon | Icon and Unicon | $define TRUE 1
$define FALSE -1
$define UNKNOWN 0
invocable all
link printf
procedure main() # demonstrate ternary logic
ufunc := ["not3"]
bfunc := ["and3", "or3", "xor3", "eq3", "ifthen3"]
every f := !ufunc do { # display unary functions
printf("\nunary function=%s:\n",f)
every t1 := (TRUE | FAL... | Give a code snippet in #Icon_and_Unicon
This page uses content from Wikipedia. The original article was at Ternary logic. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In logic, a three-valued l... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include ... | #Oforth | Oforth | aBoolean ifTrue: [ ...]
aBoolean ifFalse: [ ... ]
aObject ifNull: [ ... ]
aObject ifNotNull: [ ... ]
aObject ifZero: [ ... ] | Give a code snippet in #Oforth
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common... | christopher/rosetta-code | |
http://rosettacode.org/wiki/DNS_query | DNS query | DNS is an internet service that maps domain names, like rosettacode.org, to IP addresses, like 66.220.0.231.
Use DNS to resolve www.kame.net to both IPv4 and IPv6 addresses. Print these addresses.
| #REXX | REXX | /*REXX program displays IPV4 and IPV6 addresses for a supplied domain name.*/
parse arg tar . /*obtain optional domain name from C.L.*/
if tar=='' then tar= 'www.kame.net' /*Not specified? Then use the default.*/
tFID = '\TEMP\DNSQUERY.$$$' /*define temp file to store IPV4 outpu... | Give a code snippet in #REXX
DNS is an internet service that maps domain names, like rosettacode.org, to IP addresses, like 66.220.0.231.
Use DNS to resolve www.kame.net to both IPv4 and IPv6 addresses. Print these addresses.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Reverse_words_in_a_string | Reverse words in a string | Task
Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified.
Example
Hey you, Bub! would be shown reversed as: Bub! you, Hey
Tokens are any non-space characters separated by spaces (formally, white-space); t... | #LiveCode | LiveCode | repeat for each line txtln in fld "Fieldtxt"
repeat with i = the number of words of txtln down to 1
put word i of txtln & space after txtrev
end repeat
put cr after txtrev -- preserve line
end repeat
put txtrev | Give a code snippet in #LiveCode
Task
Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified.
Example
Hey you, Bub! would be shown reversed as: Bub! you, Hey
Tokens are any non-space characters separated by s... | 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... | #REALbasic | REALbasic |
Sub PrintArgs(ParamArray Args() As String)
For i As Integer = 0 To Ubound(Args)
Print(Args(i))
Next
End Sub
| Give a code snippet in #REALbasic
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.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Levenshtein_distance | Levenshtein distance |
This page uses content from Wikipedia. The original article was at Levenshtein distance. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In information theory and computer science, the Levenshtein ... | #Io | Io | Io 20110905
Io> Range ; "kitten" levenshtein("sitting")
==> 3
Io> "rosettacode" levenshtein("raisethysword")
==> 8
Io> | Give a code snippet in #Io
This page uses content from Wikipedia. The original article was at Levenshtein distance. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In information theory and comput... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #JavaScript | JavaScript | (() => {
'use strict';
// attractiveNumbers :: () -> Gen [Int]
const attractiveNumbers = () =>
// An infinite series of attractive numbers.
filter(
compose(isPrime, length, primeFactors)
)(enumFrom(1));
// ----------------------- TEST -----------------------
... | Give a code snippet in #JavaScript
A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Ta... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_interpolation_(included) | String interpolation (included) |
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 |... | #Scala | Scala | object StringInterpolation extends App {
import util.matching.Regex._
val size = "little"
{ // Method I (preferred)
// Scala 2.10.0 supports direct string interpolation
// by putting "s" at the beginning of the string.
println("V2.10+ : " + s"Mary had a $size lamb,")
}
{ // Method II
//... | Give a code snippet in #Scala
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_concatenation | Array concatenation | Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| #Erlang | Erlang |
1> [1, 2, 3] ++ [4, 5, 6].
[1,2,3,4,5,6]
2> lists:append([1, 2, 3], [4, 5, 6]).
[1,2,3,4,5,6]
3>
| Give a code snippet in #Erlang
Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Quicksort | Sorting algorithms/Quicksort |
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
... | #AArch64_Assembly | AArch64 Assembly |
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program quickSort64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeConstantesAR... | Give a code snippet in #AArch64_Assembly
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\di... | #Julia | Julia | using Primes, Printf
function strfactor(n::Integer)
n > -2 || return "-1 × " * strfactor(-n)
isprime(n) || n < 2 && return dec(n)
f = factor(Vector{typeof(n)}, n)
return join(f, " × ")
end
lo, hi = -4, 40
println("Factor print $lo to $hi:")
for n in lo:hi
@printf("%5d = %s\n", n, strfactor(n))
end | Give a code snippet in #Julia
Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would... | christopher/rosetta-code | |
http://rosettacode.org/wiki/List_comprehensions | List comprehensions | A list comprehension is a special syntax in some programming languages to describe lists. It is similar to the way mathematicians describe sets, with a set comprehension, hence the name.
Some attributes of a list comprehension are:
They should be distinct from (nested) for loops and the use of map and filter functio... | #Raku | Raku | my $n = 20;
gather for 1..$n -> $x {
for $x..$n -> $y {
for $y..$n -> $z {
take $x,$y,$z if $x*$x + $y*$y == $z*$z;
}
}
} | Give a code snippet in #Raku
A list comprehension is a special syntax in some programming languages to describe lists. It is similar to the way mathematicians describe sets, with a set comprehension, hence the name.
Some attributes of a list comprehension are:
They should be distinct from (nested) for loops and the... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Intersecting_number_wheels | Intersecting number wheels | A number wheel has:
A name which is an uppercase letter.
A set of ordered values which are either numbers or names.
A number is generated/yielded from a named wheel by:
1. Starting at the first value of the named wheel and advancing through subsequent values and wrapping around to the first value to form a "wheel"... | #C.2B.2B | C++ | #include <initializer_list>
#include <iostream>
#include <map>
#include <vector>
struct Wheel {
private:
std::vector<char> values;
size_t index;
public:
Wheel() : index(0) {
// empty
}
Wheel(std::initializer_list<char> data) : values(data), index(0) {
//values.assign(data);
... | Give a code snippet in #C.2B.2B
A number wheel has:
A name which is an uppercase letter.
A set of ordered values which are either numbers or names.
A number is generated/yielded from a named wheel by:
1. Starting at the first value of the named wheel and advancing through subsequent values and wrapping around to ... | 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 ... | #Seed7 | Seed7 | $ include "seed7_05.s7i";
const proc: main is func
begin
writeln(fileType("input.txt") = FILE_REGULAR);
writeln(fileType("/input.txt") = FILE_REGULAR);
writeln(fileType("docs") = FILE_DIR);
writeln(fileType("/docs") = FILE_DIR);
end func; | Give a code snippet in #Seed7
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 wit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Identity_matrix | Identity matrix | Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
1
⋯
0
⋮
⋮
⋮
⋱
... | #Haskell | Haskell | matI n = [ [fromEnum $ i == j | i <- [1..n]] | j <- [1..n]] | Give a code snippet in #Haskell
Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Semordnilap | Semordnilap | A semordnilap is a word (or phrase) that spells a different word (or phrase) backward. "Semordnilap" is a word that itself is a semordnilap.
Example: lager and regal
Task
This task does not consider semordnilap phrases, only single words.
Using only words from this list, report the total number of unique semordnilap ... | #D | D | void main() {
import std.stdio, std.file, std.string, std.algorithm;
bool[string] seenWords;
size_t pairCount = 0;
foreach (const word; "unixdict.txt".readText.toLower.splitter) {
//const drow = word.dup.reverse();
auto drow = word.dup;
drow.reverse();
if (drow in see... | Give a code snippet in #D
A semordnilap is a word (or phrase) that spells a different word (or phrase) backward. "Semordnilap" is a word that itself is a semordnilap.
Example: lager and regal
Task
This task does not consider semordnilap phrases, only single words.
Using only words from this list, report the total nu... | 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... | #F.23 | F# | [<EntryPoint>]
let main argv =
let fs = List.init 10 (fun i -> fun () -> i*i)
do List.iter (fun f -> printfn "%d" <| f()) fs
0 | Give a code snippet in #F.23
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.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Fantom | Fantom |
// create an enumeration with named constants
enum class Fruits { apple, banana, orange }
| Give a code snippet in #Fantom
Task
Create an enumeration of constants with and without explicit values.
| 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... | #CoffeeScript | CoffeeScript |
last_friday_of_month = (year, month) ->
# month is 1-based, JS API is 0-based, then we use
# non-positive indexes to work backward relative to the
# first day of the next month
i = 0
while true
last_day = new Date(year, month, i)
if last_day.getDay() == 5
return last_day.toDateString()
i ... | Give a code snippet in #CoffeeScript
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-... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Look-and-say_sequence | Look-and-say sequence | The Look and say sequence is a recursively defined sequence of numbers studied most notably by John Conway.
The look-and-say sequence is also known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle What is the next number in the sequence 1, 11, 21, 1211, 11122... | #Sather | Sather | class MAIN is
look_and_say!: STR is
current ::= "1";
loop
yield current;
buf ::= #FSTR;
last ::= current[0];
count ::= 0;
loop
ch ::= current.elt!;
if ch /= last then
buf := buf + count + last;
last := ch; ... | Give a code snippet in #Sather
The Look and say sequence is a recursively defined sequence of numbers studied most notably by John Conway.
The look-and-say sequence is also known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle What is the next number in the sequenc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_comparison | String comparison |
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 |... | #Apex | Apex | public class Compare
{
/**
* Test in the developer console:
* Compare.compare('Hello', 'Hello');
* Compare.compare('5', '5.0');
* Compare.compare('java', 'Java');
* Compare.compare('ĴÃVÁ', 'ĴÃVÁ');
*/
public static void compare (String A, String B)
{
if (A.equals(B))
System.deb... | Give a code snippet in #Apex
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
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/JSON | JSON | Load a JSON string into a data structure.
Also, create a new data structure and serialize it into JSON.
Use objects and arrays (as appropriate for your language)
and make sure your JSON is valid (https://jsonformatter.org).
| #Python | Python | >>> import json
>>> data = json.loads('{ "foo": 1, "bar": [10, "apples"] }')
>>> sample = { "blue": [1,2], "ocean": "water" }
>>> json_string = json.dumps(sample)
>>> json_string
'{"blue": [1, 2], "ocean": "water"}'
>>> sample
{'blue': [1, 2], 'ocean': 'water'}
>>> data
{'foo': 1, 'bar': [10, 'apples']} | Give a code snippet in #Python
Load a JSON string into a data structure.
Also, create a new data structure and serialize it into JSON.
Use objects and arrays (as appropriate for your language)
and make sure your JSON is valid (https://jsonformatter.org).
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Simple_moving_average | Averages/Simple moving average | Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is a method for computing an avera... | #Icon_and_Unicon | Icon and Unicon | procedure main(A)
sma := buildSMA(3) # Use better name than "I".
every write(sma(!A))
end
procedure buildSMA(P)
local stream
c := create {
stream := []
while n := (avg@&source)[1] do {
put(stream, n)
if *stream > P then pop(stream)
every (avg := 0.0) +... | Give a code snippet in #Icon_and_Unicon
Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/PPM_conversion_through_a_pipe | Bitmap/PPM conversion through a pipe | Using the data storage type defined on this page for raster images, delegate writing a JPEG file through a pipe using the output_ppm function defined on this other page.
There are various utilities that can be used for this task, for example: cjpeg (package "jpeg-progs" on Linux), ppmtojpeg (package "netpbm" on Linux)... | #Julia | Julia | using Images, FileIO
ppmimg = load("data/bitmapInputTest.ppm")
save("data/bitmapOutputTest.jpg", ppmimg) | Give a code snippet in #Julia
Using the data storage type defined on this page for raster images, delegate writing a JPEG file through a pipe using the output_ppm function defined on this other page.
There are various utilities that can be used for this task, for example: cjpeg (package "jpeg-progs" on Linux), ppmtoj... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_largest_left_truncatable_prime_in_a_given_base | Find largest left truncatable prime in a given base | A truncatable prime is one where all non-empty substrings that finish at the end of the number (right-substrings) are also primes when understood as numbers in a particular base. The largest such prime in a given (integer) base is therefore computable, provided the base is larger than 2.
Let's consider what happens in... | #Fortran | Fortran | USE PRIMEBAG !Gain access to NEXTPRIME and ISPRIME.
Calculates the largest "left-truncatable" digit sequence that is a prime number, in various bases.
INTEGER LBASE,MANY,ENUFF !Some sizes.
PARAMETER (LBASE = 13, MANY = 66666, ENUFF = 66)
INTEGER NS,START(LBASE) !A list of single-digit prime numb... | Give a code snippet in #Fortran
A truncatable prime is one where all non-empty substrings that finish at the end of the number (right-substrings) are also primes when understood as numbers in a particular base. The largest such prime in a given (integer) base is therefore computable, provided the base is larger than 2... | christopher/rosetta-code | |
http://rosettacode.org/wiki/World_Cup_group_stage | World Cup group stage | It's World Cup season (or at least it was when this page was created)!
The World Cup is an international football/soccer tournament that happens every 4 years. Countries put their international teams together in the years between tournaments and qualify for the tournament based on their performance in other internat... | #C | C | #include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// to supply to qsort
int compare(const void *a, const void *b) {
int int_a = *((int *)a);
int int_b = *((int *)b);
return (int_a > int_b) - (int_a < int_b);
}
char results[7];
bool next_result() {
char *ptr = results + ... | Give a code snippet in #C
It's World Cup season (or at least it was when this page was created)!
The World Cup is an international football/soccer tournament that happens every 4 years. Countries put their international teams together in the years between tournaments and qualify for the tournament based on their pe... | christopher/rosetta-code |
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