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/Echo_server | Echo server | Create a network service that sits on TCP port 12321, which accepts connections on that port, and which echoes complete lines (using a carriage-return/line-feed sequence as line separator) back to clients. No error handling is required. For the purposes of testing, it is only necessary to support connections from local... | #Scala | Scala | import java.io.PrintWriter
import java.net.{ServerSocket, Socket}
import scala.io.Source
object EchoServer extends App {
private val serverSocket = new ServerSocket(23)
private var numConnections = 0
class ClientHandler(clientSocket: Socket) extends Runnable {
private val (connectionId, closeCmd) = ({nu... | Give a code snippet in #Scala
Create a network service that sits on TCP port 12321, which accepts connections on that port, and which echoes complete lines (using a carriage-return/line-feed sequence as line separator) back to clients. No error handling is required. For the purposes of testing, it is only necessary to... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Detect_division_by_zero | Detect division by zero | Task
Write a function to detect a divide by zero error without checking if the denominator is zero.
| #Maxima | Maxima | f(a, b) := block([q: errcatch(a / b)], if emptyp(q) then 'error else q[1]);
f(5, 6);
5 / 6
f(5, 0;)
'error | Give a code snippet in #Maxima
Task
Write a function to detect a divide by zero error without checking if the denominator is zero.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion | Gauss-Jordan matrix inversion | Task
Invert matrix A using Gauss-Jordan method.
A being an n × n matrix.
| #11l | 11l | V Eps = 1e-10
F transformToRref(&mat)
V lead = 0
L(r) 0 .< mat.len
I lead >= mat[0].len
R
V i = r
L mat[i][lead] == 0
i++
I i == mat.len
i = r
lead++
I lead == mat[0].len
R
swap(&mat[i], &mat[r])
V ... | Give a code snippet in #11l
Task
Invert matrix A using Gauss-Jordan method.
A being an n × n matrix.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Set | Set |
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 set is a collection of elements, without duplicates and without order.
Task
Show each of these set operations:
Set creation
Test m ∈ S -- "m is an... | #Apex | Apex |
public class MySetController{
public Set<String> strSet {get; private set; }
public Set<Id> idSet {get; private set; }
public MySetController(){
//Initialize to an already known collection. Results in a set of abc,def.
this.strSet = new Set<String>{'abc','abc','def'};
//Initia... | Give a code snippet in #Apex
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 set is a collection of elements, without duplicates and without order.
Task
Show each of these set operations:
Set cr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Jump_anywhere | Jump anywhere | Imperative programs
conditional structures
loops
local jumps
This task is to demonstrate a local jump and a global jump and the various other types of jumps that the language supports.
For the purpose of this task, the jumps need not be used for a single purpose and you have the freedom to use these jumps for different... | #FBSL | FBSL | \ this prints five lines containing elements from the two
\ words 'proc1' and 'proc2'. gotos are used here to jump
\ into and out of the two words at various points, as well
\ as to create a loop. this functions with ficl, pfe,
\ gforth, bigforth, swiftforth, iforth, and vfxforth; it
\ may work with other forths as wel... | Give a code snippet in #FBSL
Imperative programs
conditional structures
loops
local jumps
This task is to demonstrate a local jump and a global jump and the various other types of jumps that the language supports.
For the purpose of this task, the jumps need not be used for a single purpose and you have the freedom to... | 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... | #Futhark | Futhark |
type complex = (f64,f64)
fun complexAdd((a,b): complex) ((c,d): complex): complex =
(a + c,
b + d)
fun complexMult((a,b): complex) ((c,d): complex): complex =
(a*c - b * d,
a*d + b * c)
fun complexInv((r,i): complex): complex =
let denom = r*r + i * i
in (r / denom,
-i / denom)
fun complexNe... | Give a code snippet in #Futhark
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
{\display... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Combinations | Combinations | Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
... | #R | R | print(combn(0:4, 3)) | Give a code snippet in #R
Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Generate_random_chess_position | Generate random chess position | Task
Generate a random chess position in FEN format.
The position does not have to be realistic or even balanced, but it must comply to the following rules:
there is one and only one king of each color (one black king and one white king);
the kings must not be placed on adjacent squares;
there can not be any p... | #Go | Go | package main
import (
"fmt"
"math/rand"
"strconv"
"strings"
"time"
)
var grid [8][8]byte
func abs(i int) int {
if i >= 0 {
return i
} else {
return -i
}
}
func createFen() string {
placeKings()
placePieces("PPPPPPPP", true)
placePieces("pppppppp", true... | Give a code snippet in #Go
Task
Generate a random chess position in FEN format.
The position does not have to be realistic or even balanced, but it must comply to the following rules:
there is one and only one king of each color (one black king and one white king);
the kings must not be placed on adjacent squa... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #MATLAB | MATLAB | >> islogical(true)
ans =
1
>> islogical(false)
ans =
1
>> islogical(logical(1))
ans =
1
>> islogical(logical(0))
ans =
1
>> islogical(1)
ans =
0
>> islogical(0)
ans =
0 | Give a code snippet in #MATLAB
Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Grayscale_image | Grayscale image | Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
To get luminance of a color u... | #Ruby | Ruby | class RGBColour
def to_grayscale
luminosity = Integer(0.2126*@red + 0.7152*@green + 0.0722*@blue)
self.class.new(luminosity, luminosity, luminosity)
end
end
class Pixmap
def to_grayscale
gray = self.class.new(@width, @height)
@width.times do |x|
@height.times do |y|
gray[x,y] = sel... | Give a code snippet in #Ruby
Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Four_bit_adder | Four bit adder | Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands ... | #J | J | and=: *.
or=: +.
not=: -.
xor=: (and not) or (and not)~
hadd=: and ,"0 xor
add=: ((({.,0:)@[ or {:@[ hadd {.@]), }.@])/@hadd | Give a code snippet in #J
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made usin... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Return_multiple_values | Return multiple values | Task
Show how to return more than one value from a function.
| #Frink | Frink |
divMod[a, b] := [a div b, a mod b]
[num, remainder] = divMod[10, 3]
| Give a code snippet in #Frink
Task
Show how to return more than one value from a function.
| 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... | #LOLCODE | LOLCODE | HAI 1.4
I HAS A integer
GIMMEH integer
I HAS A remainder
remainder R MOD OF integer AN 2
BOTH SAEM remainder AN 1, O RLY?
YA RLY
VISIBLE "The integer is odd."
NO WAI
VISIBLE "The integer is even."
OIC
KTHXBYE | Give a code snippet in #LOLCODE
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.
Di... | christopher/rosetta-code | |
http://rosettacode.org/wiki/XML/Input | XML/Input | Given the following XML fragment, extract the list of student names using whatever means desired. If the only viable method is to use XPath, refer the reader to the task XML and XPath.
<Students>
<Student Name="April" Gender="F" DateOfBirth="1989-01-02" />
<Student Name="Bob" Gender="M" DateOfBirth="1990-03-04" /... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | Column[Cases[Import["test.xml","XML"],Rule["Name", n_ ] -> n,Infinity]] | Give a code snippet in #Mathematica.2FWolfram_Language
Given the following XML fragment, extract the list of student names using whatever means desired. If the only viable method is to use XPath, refer the reader to the task XML and XPath.
<Students>
<Student Name="April" Gender="F" DateOfBirth="1989-01-02" />
<S... | christopher/rosetta-code | |
http://rosettacode.org/wiki/UTF-8_encode_and_decode | UTF-8 encode and decode | As described in UTF-8 and in Wikipedia, UTF-8 is a popular encoding of (multi-byte) Unicode code-points into eight-bit octets.
The goal of this task is to write a encoder that takes a unicode code-point (an integer representing a unicode character) and returns a sequence of 1-4 bytes representing that character in the... | #Scala | Scala | object UTF8EncodeAndDecode extends App {
val codePoints = Seq(0x0041, 0x00F6, 0x0416, 0x20AC, 0x1D11E)
def utf8Encode(codepoint: Int): Array[Byte] =
new String(Array[Int](codepoint), 0, 1).getBytes(StandardCharsets.UTF_8)
def utf8Decode(bytes: Array[Byte]): Int =
new String(bytes, StandardCharsets.U... | Give a code snippet in #Scala
As described in UTF-8 and in Wikipedia, UTF-8 is a popular encoding of (multi-byte) Unicode code-points into eight-bit octets.
The goal of this task is to write a encoder that takes a unicode code-point (an integer representing a unicode character) and returns a sequence of 1-4 bytes rep... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Knight%27s_tour | Knight's tour |
Task
Problem: you have a standard 8x8 chessboard, empty but for a single knight on some square. Your task is to emit a series of legal knight moves that result in the knight visiting every square on the chessboard exactly once. Note that it is not a requirement that the tour be "closed"; that is, the knight need not e... | #Bracmat | Bracmat | ( knightsTour
= validmoves WarnsdorffSort algebraicNotation init solve
, x y fieldsToVisit
. ~
| ( validmoves
= x y jumps moves
. !arg:(?x.?y)
& :?moves
& ( jumps
= dx dy Fs fxs fys fx fy
. !arg:(?dx.... | Give a code snippet in #Bracmat
Task
Problem: you have a standard 8x8 chessboard, empty but for a single knight on some square. Your task is to emit a series of legal knight moves that result in the knight visiting every square on the chessboard exactly once. Note that it is not a requirement that the tour be "closed... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Runge-Kutta_method | Runge-Kutta method | Given the example Differential equation:
y
′
(
t
)
=
t
×
y
(
t
)
{\displaystyle y'(t)=t\times {\sqrt {y(t)}}}
With initial condition:
t
0
=
0
{\displaystyle t_{0}=0}
and
y
0
=
y
(
t
0
)
=
y
(
0
)
=
1
{\displaystyle y_{0}=y(t_{0})=y(0)=1}
This equation has an exact solution:
... | #J | J | NB.*rk4 a Solve function using Runge-Kutta method
NB. y is: y(ta) , ta , tb , tstep
NB. u is: function to solve
NB. eg: fyp rk4 1 0 10 0.1
rk4=: adverb define
'Y0 a b h'=. 4{. y
T=. a + i.@>:&.(%&h) b - a
Y=. Yt=. Y0
for_t. }: T do.
ty=. t,Yt
k1=. h * u ty
k2=. h * u ty + -: h,k1
k3=. h * u ty + -: h,k... | Give a code snippet in #J
Given the example Differential equation:
y
′
(
t
)
=
t
×
y
(
t
)
{\displaystyle y'(t)=t\times {\sqrt {y(t)}}}
With initial condition:
t
0
=
0
{\displaystyle t_{0}=0}
and
y
0
=
y
(
t
0
)
=
y
(
0
)
=
1
{\displaystyle y_{0}=y(t_{0})=y(0)=1}
This equati... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Keyboard_input/Obtain_a_Y_or_N_response | Keyboard input/Obtain a Y or N response |
Task
Obtain a valid Y or N response from the keyboard.
The keyboard should be flushed, so that any outstanding key-presses are removed, preventing any existing Y or N key-press from being evaluated.
The response should be obtained as soon as Y or N are pressed, and there should be no need t... | #F.23 | F# | open System
let rec yorn () =
let rec flush () = if Console.KeyAvailable then ignore (Console.ReadKey()); flush ()
flush ()
printf "\nY or N? "
match Console.ReadKey().Key with
| ConsoleKey.Y -> 'Y'
| ConsoleKey.N -> 'N'
| _ -> yorn()
printfn "\nYour choice: %c" (yorn()) | Give a code snippet in #F.23
Task
Obtain a valid Y or N response from the keyboard.
The keyboard should be flushed, so that any outstanding key-presses are removed, preventing any existing Y or N key-press from being evaluated.
The response should be obtained as soon as Y or N are pressed,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ordered_words | Ordered words | An ordered word is a word in which the letters appear in alphabetic order.
Examples include abbey and dirt.
Task[edit]
Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.
(Examples that access the dictionary file locally assume that you have download... | #OCaml | OCaml | let input_line_opt ic =
try Some(input_line ic)
with End_of_file -> None
(* load each line in a list *)
let read_lines ic =
let rec aux acc =
match input_line_opt ic with
| Some line -> aux (line :: acc)
| None -> (List.rev acc)
in
aux []
let char_list_of_string str =
let lst = ref [] in
S... | Give a code snippet in #OCaml
An ordered word is a word in which the letters appear in alphabetic order.
Examples include abbey and dirt.
Task[edit]
Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.
(Examples that access the dictionary file locall... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dragon_curve | Dragon curve |
Create and display a dragon curve fractal.
(You may either display the curve directly or write it to an image file.)
Algorithms
Here are some brief notes the algorithms used and how they might suit various languages.
Recursively a right curling dragon is a right dragon followed by a left dragon, at 90-degree an... | #POV-Ray | POV-Ray | # handy constants with script-wide scope
[Single]$script:QUARTER_PI=0.7853982
[Single]$script:HALF_PI=1.570796
# leverage GDI (Forms and Drawing)
Add-Type -AssemblyName System.Drawing
Add-Type -AssemblyName System.Windows.Forms
$script:TurtlePen = New-Object Drawing.Pen darkGreen
$script:Form = New-Object Windows.For... | Give a code snippet in #POV-Ray
Create and display a dragon curve fractal.
(You may either display the curve directly or write it to an image file.)
Algorithms
Here are some brief notes the algorithms used and how they might suit various languages.
Recursively a right curling dragon is a right dragon followed ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Maze_solving | Maze solving | Task
For a maze generated by this task, write a function
that finds (and displays) the shortest path between two cells.
Note that because these mazes are generated by the Depth-first search algorithm, they contain no circular paths,
and a simple depth-first tree search can be used.
| #C.2B.2B | C++ |
#include <windows.h>
#include <iostream>
#include <string>
//--------------------------------------------------------------------------------------------------
using namespace std;
//--------------------------------------------------------------------------------------------------
const int BMP_SIZE = 512, CELL_S... | Give a code snippet in #C.2B.2B
Task
For a maze generated by this task, write a function
that finds (and displays) the shortest path between two cells.
Note that because these mazes are generated by the Depth-first search algorithm, they contain no circular paths,
and a simple depth-first tree search can be used.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Cocktail_sort | Sorting algorithms/Cocktail sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Julia | Julia | function cocktailsort(a::Vector)
b = copy(a)
isordered = false
lo, hi = 1, length(b)
while !isordered && hi > lo
isordered = true
for i in lo+1:hi
if b[i] < b[i-1]
b[i-1], b[i] = b[i], b[i-1]
isordered = false
end
end
... | Give a code snippet in #Julia
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 so... | 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... | #friendly_interactive_shell | friendly interactive shell |
units = array[units[volume]]
showApproximations[false]
for n = 99 to 0 step -1
{
unit = units.removeRandom[]
str = getBottleString[n, unit]
println["$str of beer on the wall, $str."]
if (n == 0)
println["Go to the store and buy some more, 99 bottles of beer on the wall."]
else
println... | Give a code snippet in #friendly_interactive_shell
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 ... | 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... | #AutoHotkey | AutoHotkey | Primitive_Heronian_triangles(MaxSide){
obj :=[]
loop, % MaxSide {
a := A_Index
loop % MaxSide-a+1 {
b := A_Index+a-1
loop % MaxSide-b+1 {
c := A_Index+b-1, s := (a+b+c)/2, Area := Sqrt(s*(s-a)*(s-b)*(s-c))
if (Area = Floor(Area)) && (Area>0) && !obj[a/s, b/s, c/s]
obj[a/s, b/s, c/s]:=1 ,res .= ... | Give a code snippet in #AutoHotkey
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
=
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Gaussian_elimination | Gaussian elimination | Task
Solve Ax=b using Gaussian elimination then backwards substitution.
A being an n by n matrix.
Also, x and b are n by 1 vectors.
To improve accuracy, please use partial pivoting and scaling.
See also
the Wikipedia entry: Gaussian elimination
| #Julia | Julia | x = A \ b | Give a code snippet in #Julia
Task
Solve Ax=b using Gaussian elimination then backwards substitution.
A being an n by n matrix.
Also, x and b are n by 1 vectors.
To improve accuracy, please use partial pivoting and scaling.
See also
the Wikipedia entry: Gaussian elimination
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available,... | #Dragon | Dragon | array = newarray(3) //optionally, replace "newarray(5)" with a brackets list of values like "[1, 2, 3]"
array[0] = 42
showln array[2] | Give a code snippet in #Dragon
This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ramanujan%27s_constant | Ramanujan's constant | Calculate Ramanujan's constant (as described on the OEIS site) with at least
32 digits of precision, by the method of your choice. Optionally, if using the 𝑒**(π*√x) approach,
show that when evaluated with the last four Heegner numbers
the result is almost an integer.
| #F.C5.8Drmul.C3.A6 | Fōrmulæ | package main
import (
"fmt"
"github.com/ALTree/bigfloat"
"math/big"
)
const (
prec = 256 // say
ps = "3.1415926535897932384626433832795028841971693993751058209749445923078164"
)
func q(d int64) *big.Float {
pi, _ := new(big.Float).SetPrec(prec).SetString(ps)
t := new(big.Float).SetPr... | Give a code snippet in #F.C5.8Drmul.C3.A6
Calculate Ramanujan's constant (as described on the OEIS site) with at least
32 digits of precision, by the method of your choice. Optionally, if using the 𝑒**(π*√x) approach,
show that when evaluated with the last four Heegner numbers
the result is almost an integer.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Factors_of_a_Mersenne_number | Factors of a Mersenne number | A Mersenne number is a number in the form of 2P-1.
If P is prime, the Mersenne number may be a Mersenne prime
(if P is not prime, the Mersenne number is also not prime).
In the search for Mersenne prime numbers it is advantageous to eliminate exponents by finding a small factor before starting a, potentially lengthy,... | #Raku | Raku | sub mtest($bits, $p) {
my @bits = $bits.base(2).comb;
loop (my $sq = 1; @bits; $sq %= $p) {
$sq ×= $sq;
$sq += $sq if 1 == @bits.shift;
}
$sq == 1;
}
for flat 2 .. 60, 929 -> $m {
next unless is-prime($m);
my $f = 0;
my $x = 2**$m - 1;
my $q;
for 1..* -> $k {
... | Give a code snippet in #Raku
A Mersenne number is a number in the form of 2P-1.
If P is prime, the Mersenne number may be a Mersenne prime
(if P is not prime, the Mersenne number is also not prime).
In the search for Mersenne prime numbers it is advantageous to eliminate exponents by finding a small factor before st... | christopher/rosetta-code | |
http://rosettacode.org/wiki/N-smooth_numbers | N-smooth numbers | n-smooth numbers are positive integers which have no prime factors > n.
The n (when using it in the expression) n-smooth is always prime,
there are no 9-smooth numbers.
1 (unity) is always included in n-smooth numbers.
2-smooth numbers are non-negative powers of two.
5-smooth numbers are... | #Quackery | Quackery |
[ behead 0 swap rot
witheach
[ 2dup < iff
drop done
nip nip
i^ 1+ swap ] ] is smallest ( [ --> n n )
[ stack ] is end.test ( --> s )
[ ]'[ end.test put
dup temp put
' [ 1 ]
0 rot size of
[ over end.test shar... | Give a code snippet in #Quackery
n-smooth numbers are positive integers which have no prime factors > n.
The n (when using it in the expression) n-smooth is always prime,
there are no 9-smooth numbers.
1 (unity) is always included in n-smooth numbers.
2-smooth numbers are non-negative powe... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Chernick%27s_Carmichael_numbers | Chernick's Carmichael numbers | In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(4, m) = U(3, m) * (2^2 * 9m + 1)... | #Wren | Wren | import "/big" for BigInt, BigInts
import "/fmt" for Fmt
var min = 3
var max = 9
var prod = BigInt.zero
var fact = BigInt.zero
var factors = List.filled(max, 0)
var bigFactors = List.filled(max, null)
var init = Fn.new {
for (i in 0...max) bigFactors[i] = BigInt.zero
}
var isPrimePretest = Fn.new { |k|
if ... | Give a code snippet in #Wren
In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(4,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Function_prototype | Function prototype | Some languages provide the facility to declare functions and subroutines through the use of function prototyping.
Task
Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include:
An explanation of any placement restrictions for prototype declarations
A p... | #Clojure | Clojure | (declare foo) | Give a code snippet in #Clojure
Some languages provide the facility to declare functions and subroutines through the use of function prototyping.
Task
Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include:
An explanation of any placement restriction... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pangram_checker | Pangram checker | Pangram checker
You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.
For example: The quick brown fox jumps over the lazy dog.
Task
Write a function or method to chec... | #F.C5.8Drmul.C3.A6 | Fōrmulæ | package main
import "fmt"
func main() {
for _, s := range []string{
"The quick brown fox jumps over the lazy dog.",
`Watch "Jeopardy!", Alex Trebek's fun TV quiz game.`,
"Not a pangram.",
} {
if pangram(s) {
fmt.Println("Yes:", s)
} else {
fmt.... | Give a code snippet in #F.C5.8Drmul.C3.A6
Pangram checker
You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.
For example: The quick brown fox jumps over the lazy dog.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Monads/Maybe_monad | Monads/Maybe monad | Demonstrate in your programming language the following:
Construct a Maybe Monad by writing the 'bind' function and the 'unit' (sometimes known as 'return') function for that Monad (or just use what the language already has implemented)
Make two functions, each which take a number and return a monadic number, e.g. Int ... | #Raku | Raku | my $monad = <42>;
say 'Is $monad an Int?: ', $monad ~~ Int;
say 'Is $monad a Str?: ', $monad ~~ Str;
say 'Wait, what? What exactly is $monad?: ', $monad.^name; | Give a code snippet in #Raku
Demonstrate in your programming language the following:
Construct a Maybe Monad by writing the 'bind' function and the 'unit' (sometimes known as 'return') function for that Monad (or just use what the language already has implemented)
Make two functions, each which take a number and retu... | 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 |... | #min | min | "$1 is $2 $3."
("Enter an integer" ask) 2 times over over
(
((>) ("greater than"))
((<) ("less than"))
((==) ("equal to"))
) case
' append prepend % print | Give a code snippet in #min
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
Co... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Long_year | Long year | Most years have 52 weeks, some have 53, according to ISO8601.
Task
Write a function which determines if a given year is long (53 weeks) or not, and demonstrate it.
| #Pascal | Pascal | program long_year(input);
var
y: integer;
function rd_dec31(year: integer): integer;
begin
{ Rata Die of Dec 31, year }
rd_dec31 := year * 365 + year div 4 - year div 100 + year div 400
end;
function rd_jan1(year: integer): integer;
begin
rd_jan1 := rd_dec31(year - 1) + 1
end;
func... | Give a code snippet in #Pascal
Most years have 52 weeks, some have 53, according to ISO8601.
Task
Write a function which determines if a given year is long (53 weeks) or not, and demonstrate it.
| 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... | #C.23 | C# | System.IO.Directory.CreateDirectory(path) | Give a code snippet in #C.23
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 director... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Greatest_subsequential_sum | Greatest subsequential sum | Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be th... | #Scala | Scala | def maxSubseq(l: List[Int]) = l.scanRight(Nil : List[Int]) {
case (el, acc) if acc.sum + el < 0 => Nil
case (el, acc) => el :: acc
} max Ordering.by((_: List[Int]).sum)
def biggestMaxSubseq(l: List[Int]) = l.scanRight(Nil : List[Int]) {
case (el, acc) if acc.sum + el < 0 => Nil
case (el, a... | Give a code snippet in #Scala
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Merge_and_aggregate_datasets | Merge and aggregate datasets | Merge and aggregate datasets
Task
Merge and aggregate two datasets as provided in .csv files into a new resulting dataset.
Use the appropriate methods and data structures depending on the programming language.
Use the most common libraries only when built-in functionality is not sufficient.
Note
Either lo... | #Raku | Raku | my @names = map { ( <PATIENT_ID LASTNAME> Z=> .list ).hash },
( 1001, 'Hopper' ),
( 4004, 'Wirth' ),
( 3003, 'Kemeny' ),
( 2002, 'Gosling' ),
( 5005, 'Kurtz' ),
;
my @visits = map { ( <PATIENT_ID VISIT_DATE SCORE> Z=> .list ).hash },
( 2002, '2020-09-10', 6.8 ),
( 1001, '2020-09-17', 5... | Give a code snippet in #Raku
Merge and aggregate datasets
Task
Merge and aggregate two datasets as provided in .csv files into a new resulting dataset.
Use the appropriate methods and data structures depending on the programming language.
Use the most common libraries only when built-in functionality is not ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pseudo-random_numbers/Xorshift_star | Pseudo-random numbers/Xorshift star | Some definitions to help in the explanation
Floor operation
https://en.wikipedia.org/wiki/Floor_and_ceiling_functions
Greatest integer less than or equal to a real number.
Bitwise Logical shift operators (c-inspired)
https://en.wikipedia.org/wiki/Bitwise_operation#Bit_shifts
Binary bits of value shifted left or ri... | #Python | Python | mask64 = (1 << 64) - 1
mask32 = (1 << 32) - 1
const = 0x2545F4914F6CDD1D
class Xorshift_star():
def __init__(self, seed=0):
self.state = seed & mask64
def seed(self, num):
self.state = num & mask64
def next_int(self):
"return random int between 0 and 2**32"
x = s... | Give a code snippet in #Python
Some definitions to help in the explanation
Floor operation
https://en.wikipedia.org/wiki/Floor_and_ceiling_functions
Greatest integer less than or equal to a real number.
Bitwise Logical shift operators (c-inspired)
https://en.wikipedia.org/wiki/Bitwise_operation#Bit_shifts
Binary ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_file_on_magnetic_tape | Create a file on magnetic tape | The task is to create a new file called "TAPE.FILE" of any size on Magnetic Tape.
| #Action.21 | Action! | PROC Save(CHAR ARRAY text)
BYTE dev=[1]
Close(dev)
Open(dev,"C:",8,128)
PrintE("Saving started...")
PrintF("Saving text: ""%S""%E",text)
PrintD(dev,text)
Close(dev)
PrintE("Saving finished.")
RETURN
PROC Load()
CHAR ARRAY result(255)
BYTE dev=[1]
Close(dev)
Open(dev,"C:",4,128)
PrintE("L... | Give a code snippet in #Action.21
The task is to create a new file called "TAPE.FILE" of any size on Magnetic Tape.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Generate_random_chess_position | Generate random chess position | Task
Generate a random chess position in FEN format.
The position does not have to be realistic or even balanced, but it must comply to the following rules:
there is one and only one king of each color (one black king and one white king);
the kings must not be placed on adjacent squares;
there can not be any p... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | g = ConstantArray["", {8, 8}];
While[Norm@First@Differences[r = RandomChoice[Tuples[Range[8], 2], 2]] <= Sqrt[2], Null];
g = ReplacePart[g, {r[[1]] -> "K", r[[2]] -> "k"}];
avail = Position[g, "", {2}];
n = RandomInteger[{2, 14}];
rls = Thread[RandomSample[avail, n] -> RandomChoice[Characters@"NBRQnbrq", n]];
g = Repla... | Give a code snippet in #Mathematica.2FWolfram_Language
Task
Generate a random chess position in FEN format.
The position does not have to be realistic or even balanced, but it must comply to the following rules:
there is one and only one king of each color (one black king and one white king);
the kings must no... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_an_HTML_table | Create an HTML table | Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled with sequential row numbers.
The... | #Lasso | Lasso | define rand4dig => integer_random(9999, 1)
local(
output = '<table border=2 cellpadding=5 cellspace=0>\n<tr>'
)
with el in (' ,X,Y,Z') -> split(',') do {
#output -> append('<th>' + #el + '</th>')
}
#output -> append('</tr>\n')
loop(5) => {
#output -> append('<tr>\n<td style="font-weight: bold;">' + loop_... | Give a code snippet in #Lasso
Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled wit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_entire_file | Read entire file | Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished incrementally instead
(in which case... | #Ring | Ring |
# Read the file
cStr = read("myfile.txt")
# print the file content
See cStr
| Give a code snippet in #Ring
Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished increm... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Bogosort | Sorting algorithms/Bogosort |
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
... | #C.2B.2B | C++ | g++ -std=c++11 bogo.cpp
| Give a code snippet in #C.2B.2B
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_append | String append |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #NS-HUBASIC | NS-HUBASIC | 10 S$ = "HELLO"
20 S$ = S$ + " WORLD!"
30 PRINT S$ | Give a code snippet in #NS-HUBASIC
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 Operat... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Test_a_function | Test a function |
Task
Using a well-known testing-specific library/module/suite for your language, write some tests for your language's entry in Palindrome.
If your language does not have a testing specific library well known to the language's community then state this or omit the language.
| #zkl | zkl | fcn pali(text){
if (text.len()<2) return(False);
text==text.reverse();
} | Give a code snippet in #zkl
Task
Using a well-known testing-specific library/module/suite for your language, write some tests for your language's entry in Palindrome.
If your language does not have a testing specific library well known to the language's community then state this or omit the language.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Numbers_with_equal_rises_and_falls | Numbers with equal rises and falls | When a number is written in base 10, adjacent digits may "rise" or "fall" as the number is read (usually from left to right).
Definition
Given the decimal digits of the number are written as a series d:
A rise is an index i such that d(i) < d(i+1)
A fall is an index i such that ... | #Java | Java | public class EqualRisesFalls {
public static void main(String[] args) {
final int limit1 = 200;
final int limit2 = 10000000;
System.out.printf("The first %d numbers in the sequence are:\n", limit1);
int n = 0;
for (int count = 0; count < limit2; ) {
if (equalRises... | Give a code snippet in #Java
When a number is written in base 10, adjacent digits may "rise" or "fall" as the number is read (usually from left to right).
Definition
Given the decimal digits of the number are written as a series d:
A rise is an index i such that d(i) < d(i+1)
A fall ... | 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.
| #BBC_BASIC | BBC BASIC | name$ = "www.kame.net"
AF_INET = 2
AF_INET6 = 23
WSASYS_STATUS_LEN = 128
WSADESCRIPTION_LEN = 256
SYS "LoadLibrary", "WS2_32.DLL" TO ws2%
SYS "GetProcAddress", ws2%, "WSAStartup" TO `WSAStartup`
SYS "GetProcAddress", ws2%, "WSACleanup" TO `WSACleanup`
SYS "Get... | Give a code snippet in #BBC_BASIC
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/Sorting_algorithms/Counting_sort | Sorting algorithms/Counting sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #360_Assembly | 360 Assembly | * Counting sort - 18/04/2020
COUNTS CSECT
USING COUNTS,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
SAVE (14,12) save previous context
ST R13,4(R15) link backward
... | Give a code snippet in #360_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 |
Q... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Parsing/RPN_calculator_algorithm | Parsing/RPN calculator algorithm | Task
Create a stack-based evaluator for an expression in reverse Polish notation (RPN) that also shows the changes in the stack as each individual token is processed as a table.
Assume an input of a correct, space separated, string of tokens of an RPN expression
Test with the RPN expression generated from the... | #Racket | Racket |
#lang racket
(define (calculate-RPN expr)
(for/fold ([stack '()]) ([token expr])
(printf "~a\t -> ~a~N" token stack)
(match* (token stack)
[((? number? n) s) (cons n s)]
[('+ (list x y s ___)) (cons (+ x y) s)]
[('- (list x y s ___)) (cons (- y x) s)]
[('* (list x y s ___)) (cons (* x ... | Give a code snippet in #Racket
Task
Create a stack-based evaluator for an expression in reverse Polish notation (RPN) that also shows the changes in the stack as each individual token is processed as a table.
Assume an input of a correct, space separated, string of tokens of an RPN expression
Test with the R... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/B%C3%A9zier_curves/Quadratic | Bitmap/Bézier curves/Quadratic | Using the data storage type defined on this page for raster images, and the draw_line function defined in this one, draw a quadratic bezier curve
(definition on Wikipedia).
| #Haskell | Haskell | {-# LANGUAGE
FlexibleInstances, TypeSynonymInstances,
ViewPatterns #-}
import Bitmap
import Bitmap.Line
import Control.Monad
import Control.Monad.ST
type Point = (Double, Double)
fromPixel (Pixel (x, y)) = (toEnum x, toEnum y)
toPixel (x, y) = Pixel (round x, round y)
pmap :: (Double -> Double) -> Point -... | Give a code snippet in #Haskell
Using the data storage type defined on this page for raster images, and the draw_line function defined in this one, draw a quadratic bezier curve
(definition on Wikipedia).
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Plasma_effect | Plasma effect | The plasma effect is a visual effect created by applying various functions, notably sine and cosine, to the color values of screen pixels. When animated (not a task requirement) the effect may give the impression of a colorful flowing liquid.
Task
Create a plasma effect.
See also
Computer Graphics Tutorial (lod... | #Perl | Perl | use Imager;
sub plasma {
my ($w, $h) = @_;
my $img = Imager->new(xsize => $w, ysize => $h);
for my $x (0 .. $w-1) {
for my $y (0 .. $h-1) {
my $hue = 4 + sin($x/19) + sin($y/9) + sin(($x+$y)/25) + sin(sqrt($x**2 + $y**2)/8);
$img->setpixel(x => $x, y => $y, color => {hs... | Give a code snippet in #Perl
The plasma effect is a visual effect created by applying various functions, notably sine and cosine, to the color values of screen pixels. When animated (not a task requirement) the effect may give the impression of a colorful flowing liquid.
Task
Create a plasma effect.
See also
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Jaro_similarity | Jaro similarity | The Jaro distance is a measure of edit distance between two strings; its inverse, called the Jaro similarity, is a measure of two strings' similarity: the higher the value, the more similar the strings are. The score is normalized such that 0 equates to no similarities and 1 is an exact match.
Definition
The... | #C | C | #include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#define TRUE 1
#define FALSE 0
#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) < (b) ? (a) : (b))
double jaro(const char *str1, const char *str2) {
// length of the strings
int str1_len = strlen(str1);
... | Give a code snippet in #C
The Jaro distance is a measure of edit distance between two strings; its inverse, called the Jaro similarity, is a measure of two strings' similarity: the higher the value, the more similar the strings are. The score is normalized such that 0 equates to no similarities and 1 is an exa... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Roots_of_unity | Roots of unity | The purpose of this task is to explore working with complex numbers.
Task
Given n, find the nth roots of unity.
| #Rust | Rust | use num::Complex;
fn main() {
let n = 8;
let z = Complex::from_polar(&1.0,&(1.0*std::f64::consts::PI/n as f64));
for k in 0..=n-1 {
println!("e^{:2}πi/{} ≈ {:>14.3}",2*k,n,z.powf(2.0*k as f64));
}
} | Give a code snippet in #Rust
The purpose of this task is to explore working with complex numbers.
Task
Given n, find the nth roots of unity.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Documentation | Documentation |
See also
Related task: Comments
Related task: Here_document
| #Gri | Gri | `My Hello Message'
Print a greeting to the user.
This is only a short greeting.
{
show "hello"
} | Give a code snippet in #Gri
See also
Related task: Comments
Related task: Here_document
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For_with_a_specified_step | Loops/For with a specified step |
Task
Demonstrate a for-loop where the step-value is greater than one.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within loop b... | #SSEM | SSEM | 10101000000000100000000000000000 0. -21 to c
00101000000001100000000000000000 1. c to 20
00101000000000100000000000000000 2. -20 to c
01101000000000010000000000000000 3. Sub. 22
10101000000001100000000000000000 4. c to 21
00000000000000110000000000000000 5. Test
01001000000001000000000000000000 6. Add 18 ... | Give a code snippet in #SSEM
Task
Demonstrate a for-loop where the step-value is greater than one.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Incr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is als... | #Common_Lisp | Common Lisp | (defpackage #:lexical-analyzer
(:use #:cl #:sb-gray)
(:export #:main))
(in-package #:lexical-analyzer)
(defconstant +lex-symbols-package+ (or (find-package :lex-symbols)
(make-package :lex-symbols)))
(defclass counting-character-input-stream (fundamental-character-input-... | Give a code snippet in #Common_Lisp
Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer... | 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 |... | #Raku | Raku | my $extra = "little";
say "Mary had a $extra lamb"; # variable interpolation
say "Mary had a { $extra } lamb"; # expression interpolation
printf "Mary had a %s lamb.\n", $extra; # standard printf
say $extra.fmt("Mary had a %s lamb"); # inside-out printf
my @lambs = <Jimmy Bobby Tommy>;
say Q :array { ... | Give a code snippet in #Raku
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/Filter | Filter | Task
Select certain elements from an Array into a new Array in a generic way.
To demonstrate, select all even numbers from an Array.
As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.
| #Raku | Raku | my @a = 1..6;
my @even = grep * %% 2, @a; | Give a code snippet in #Raku
Task
Select certain elements from an Array into a new Array in a generic way.
To demonstrate, select all even numbers from an Array.
As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Repeat | Repeat | Task
Write a procedure which accepts as arguments another procedure and a positive integer.
The latter procedure is executed a number of times equal to the accepted integer.
| #zkl | zkl | fcn repeat(f,n){ do(n){ f() } }
repeat("ho ".print,3); | Give a code snippet in #zkl
Task
Write a procedure which accepts as arguments another procedure and a positive integer.
The latter procedure is executed a number of times equal to the accepted integer.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Higher-order_functions | Higher-order functions | Task
Pass a function as an argument to another function.
Related task
First-class functions
| #Delphi | Delphi | type TFnType = function(x : Float) : Float;
function First(f : TFnType) : Float;
begin
Result := f(1) + 2;
end;
function Second(f : Float) : Float;
begin
Result := f/2;
end;
PrintLn(First(Second)); | Give a code snippet in #Delphi
Task
Pass a function as an argument to another function.
Related task
First-class functions
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Symmetric_difference | Symmetric difference | Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{\displaystyle (A\cup B)\setminus (A... | #C.2B.2B | C++ | #include <iostream>
#include <set>
#include <algorithm>
#include <iterator>
#include <string>
using namespace std;
int main( ) {
string setA[] = { "John", "Bob" , "Mary", "Serena" };
string setB[] = { "Jim" , "Mary", "John", "Bob" };
set<string>
firstSet( setA , setA + 4 ),
secondSet( setB ... | Give a code snippet in #C.2B.2B
Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{\d... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Regular_expressions | Regular expressions |
Task
match a string against a regular expression
substitute part of a string using a regular expression
| #Java | Java | String str = "I am a string";
if (str.matches(".*string")) { // note: matches() tests if the entire string is a match
System.out.println("ends with 'string'");
} | Give a code snippet in #Java
Task
match a string against a regular expression
substitute part of a string using a regular expression
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Forward_difference | Forward difference | Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer elem... | #jq | jq | # If n is a non-negative number and if input is
# a (possibly empty) array of numbers,
# emit an array, even if the input list is too short:
def ndiff(n):
if n==0 then .
elif n == 1 then . as $in | [range(1;length) | $in[.] - $in[.-1]]
else ndiff(1) | ndiff(n-1)
end; | Give a code snippet in #jq
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Repeat_a_string | Repeat a string | Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****").
Other tasks re... | #Ada | Ada | with Ada.Strings.Fixed; use Ada.Strings.Fixed;
with Ada.Text_IO; use Ada.Text_IO;
procedure String_Multiplication is
begin
Put_Line (5 * "ha");
end String_Multiplication; | Give a code snippet in #Ada
Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) =>... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cantor_set | Cantor set | Task
Draw a Cantor set.
See details at this Wikipedia webpage: Cantor set
| #Phix | Phix | integer n = 5,
w = power(3,n-1),
len = w
string line = repeat('#',w)&"\n"
while 1 do
puts(1,line)
if len=1 then exit end if
len /= 3
integer pos = 1
while pos<(w-len) do
pos += len
line[pos..pos+len-1] = ' '
pos += len
end while
end while
| Give a code snippet in #Phix
Task
Draw a Cantor set.
See details at this Wikipedia webpage: Cantor set
| 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).
| #jq | jq | . | Give a code snippet in #jq
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/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of ... | #Modula-3 | Modula-3 | MODULE Yule EXPORTS Main;
IMPORT IO, Fmt, Date, Time;
VAR date: Date.T;
time: Time.T;
BEGIN
FOR year := 2008 TO 2121 DO
date.day := 25;
date.month := Date.Month.Dec;
date.year := year;
TRY
time := Date.ToTime(date);
EXCEPT
| Date.Error =>
IO.Put(Fmt.Int(year) & " is th... | Give a code snippet in #Modula-3
A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years betwe... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Towers_of_Hanoi | Towers of Hanoi | Task
Solve the Towers of Hanoi problem with recursion.
| #IS-BASIC | IS-BASIC | 100 PROGRAM "Hanoi.bas"
110 CALL HANOI(4,1,3,2)
120 DEF HANOI(DISK,FRO,TO,WITH)
130 IF DISK>0 THEN
140 CALL HANOI(DISK-1,FRO,WITH,TO)
150 PRINT "Move disk";DISK;"from";FRO;"to";TO
160 CALL HANOI(DISK-1,WITH,TO,FRO)
170 END IF
180 END DEF | Give a code snippet in #IS-BASIC
Task
Solve the Towers of Hanoi problem with recursion.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Quine | Quine | A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program ... | #OxygenBasic | OxygenBasic | 'RUNTIME COMPILING
source="print source"
a=compile source : call a : freememory a | Give a code snippet in #OxygenBasic
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer prog... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anagrams | Anagrams | When two or more words are composed of the same characters, but in a different order, they are called anagrams.
Task[edit]
Using the word list at http://wiki.puzzlers.org/pub/wordlists/unixdict.txt,
find the sets of words that share the same characters that contain the most words in them.
Related tasks
Word plays
... | #K | K | {x@&a=|/a:#:'x}{x g@&1<#:'g:={x@<x}'x}0::`unixdict.txt | Give a code snippet in #K
When two or more words are composed of the same characters, but in a different order, they are called anagrams.
Task[edit]
Using the word list at http://wiki.puzzlers.org/pub/wordlists/unixdict.txt,
find the sets of words that share the same characters that contain the most words in them.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/User_input/Text | User input/Text | User input/Text is part of Short Circuit's Console Program Basics selection.
Task
Input a string and the integer 75000 from the text console.
See also: User input/Graphical
| #PHP | PHP | #!/usr/bin/php
<?php
$string = fgets(STDIN);
$integer = (int) fgets(STDIN); | Give a code snippet in #PHP
User input/Text is part of Short Circuit's Console Program Basics selection.
Task
Input a string and the integer 75000 from the text console.
See also: User input/Graphical
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Exceptions | Exceptions | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
This task is to give an example of an exception handling routine
and to "throw" a new exception.
Related task
Exceptions Through Nested Calls
| #Lingo | Lingo | -- parent script "ErrorHandler"
on alertHook (me, errorType, errorMessage, alertType)
if alertType=#alert then return 0 -- ignore programmatic alerts
-- log error in file "error.log"
fn = _movie.path&"error.log"
fp = xtra("fileIO").new()
fp.openFile(fn, 2)
if fp.status() = -37 then
fp.createFile(fn)... | Give a code snippet in #Lingo
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
This task is to give an example of an exception handling routine
and to "throw" a new exception.
Related task
Exceptions... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Department_numbers | Department numbers | There is a highly organized city that has decided to assign a number to each of their departments:
police department
sanitation department
fire department
Each department can have a number between 1 and 7 (inclusive).
The three department numbers are to be unique (different from each other) and mu... | #Arturo | Arturo | loop 1..7 'x [
loop 1..7 'y [
loop 1..7 'z [
if all? @[
even? x
12 = sum @[x y z]
3 = size unique @[x y z]
] -> print [x y z]
]
]
] | Give a code snippet in #Arturo
There is a highly organized city that has decided to assign a number to each of their departments:
police department
sanitation department
fire department
Each department can have a number between 1 and 7 (inclusive).
The three department numbers are to be unique (d... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Symmetric_difference | Symmetric difference | Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{\displaystyle (A\cup B)\setminus (A... | #FreeBASIC | FreeBASIC |
redim shared as string Result(-1) 'represent our sets as strings;
'this'll do to illustrate the concept
sub sym( A() as string, B() as string )
dim as integer ai, bi, ri
dim as boolean add_it
for ai = lbound(A) to ubound(A)
add_it = true
for bi = lbound(... | Give a code snippet in #FreeBASIC
Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Call_a_function | Call a function | Task
Demonstrate the different syntax and semantics provided for calling a function.
This may include:
Calling a function that requires no arguments
Calling a function with a fixed number of arguments
Calling a function with optional arguments
Calling a function with a variable number of arguments
C... | #Dyalect | Dyalect | func foo() { }
foo() | Give a code snippet in #Dyalect
Task
Demonstrate the different syntax and semantics provided for calling a function.
This may include:
Calling a function that requires no arguments
Calling a function with a fixed number of arguments
Calling a function with optional arguments
Calling a function with a ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Guess_the_number | Guess the number | Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, a... | #LiveCode | LiveCode | command guessTheNumber
local tNumber, tguess
put random(10) into tNumber
repeat until tguess is tNumber
ask question "Please enter a number between 1 and 10" titled "Guess the number"
if it is not empty then
put it into tguess
if tguess is tNumber then
... | Give a code snippet in #LiveCode
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call | Respond to an unknown method call | Task
Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions.
Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defin... | #Forth | Forth | include FMS-SI.f
include FMS-SILib.f
var x \ instantiate a class var object named x
x add: \ => "aborted: message not understood"
| Give a code snippet in #Forth
Task
Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions.
Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Tic-tac-toe | Tic-tac-toe |
Task
Play a game of tic-tac-toe.
Ensure that legal moves are played and that a winning position is notified.
Tic-tac-toe is also known as:
naughts and crosses
tic tac toe
tick tack toe
three in a row
tres en rayo and
Xs and Os
See also
MathWorld™, Tic-Tac-Toe game.
Wikipedi... | #Scala | Scala | package object tictactoe {
val Human = 'X'
val Computer = 'O'
val BaseBoard = ('1' to '9').toList
val WinnerLines = List((0,1,2), (3,4,5), (6,7,8), (0,3,6), (1,4,7), (2,5,8), (0,4,8), (2,4,6))
val randomGen = new util.Random(System.currentTimeMillis)
}
package tictactoe {
class Board(aBoard : List[Char]... | Give a code snippet in #Scala
Task
Play a game of tic-tac-toe.
Ensure that legal moves are played and that a winning position is notified.
Tic-tac-toe is also known as:
naughts and crosses
tic tac toe
tick tack toe
three in a row
tres en rayo and
Xs and Os
See also
MathWorld™... | 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... | #Groovy | Groovy | def printAll( Object[] args) { args.each{ arg -> println arg } }
printAll(1, 2, "three", ["3", "4"]) | Give a code snippet in #Groovy
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/Spiral_matrix | Spiral matrix | Task
Produce a spiral array.
A spiral array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you go around the edges of the array spiraling inwards.
For example, given 5, produce this array:
0 1 2 3 4
15 16 17 18 5
14 23 24 19 6
13 22 21 ... | #JavaScript | JavaScript | spiralArray = function (edge) {
var arr = Array(edge),
x = 0, y = edge,
total = edge * edge--,
dx = 1, dy = 0,
i = 0, j = 0;
while (y) arr[--y] = [];
while (i < total) {
arr[y][x] = i++;
x += dx; y += dy;
if (++j == edge) {
if (dy < 0) {x++... | Give a code snippet in #JavaScript
Task
Produce a spiral array.
A spiral array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you go around the edges of the array spiraling inwards.
For example, given 5, produce this array:
0 1 2 3 4
15 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Repeat_a_string | Repeat a string | Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****").
Other tasks re... | #Wren | Wren | System.print("ha" * 5) | Give a code snippet in #Wren
Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) =... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mayan_calendar | Mayan calendar | The ancient Maya people had two somewhat distinct calendar systems.
In somewhat simplified terms, one is a cyclical calendar known as The Calendar Round,
that meshes several sacred and civil cycles; the other is an offset calendar
known as The Long Count, similar in many ways to the Gregorian calendar.
The Calendar R... | #Perl | Perl | use strict;
use warnings;
use utf8;
binmode STDOUT, ":utf8";
use Math::BaseArith;
use Date::Calc 'Delta_Days';
my @sacred = qw<Imix’ Ik’ Ak’bal K’an Chikchan Kimi Manik’ Lamat Muluk Ok
Chuwen Eb Ben Hix Men K’ib’ Kaban Etz’nab’ Kawak Ajaw>;
my @civil = qw<Pop Wo’ Sip Sotz’ Sek Xul Yaxk’in Mol Ch’en Ya... | Give a code snippet in #Perl
The ancient Maya people had two somewhat distinct calendar systems.
In somewhat simplified terms, one is a cyclical calendar known as The Calendar Round,
that meshes several sacred and civil cycles; the other is an offset calendar
known as The Long Count, similar in many ways to the Grego... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Web_scraping | Web scraping | Task
Create a program that downloads the time from this URL: http://tycho.usno.navy.mil/cgi-bin/timer.pl and then prints the current UTC time by extracting just the UTC time from the web page's HTML. Alternatively, if the above url is not working, grab the first date/time off this page's talk page.
If possible,... | #Perl | Perl | use LWP::Simple;
my $url = 'http://tycho.usno.navy.mil/cgi-bin/timer.pl';
get($url) =~ /<BR>(.+? UTC)/
and print "$1\n"; | Give a code snippet in #Perl
Task
Create a program that downloads the time from this URL: http://tycho.usno.navy.mil/cgi-bin/timer.pl and then prints the current UTC time by extracting just the UTC time from the web page's HTML. Alternatively, if the above url is not working, grab the first date/time off this pag... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_length | Array length | Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I befo... | #Scala | Scala |
println(Array("apple", "orange").length)
| Give a code snippet in #Scala
Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequ... | 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... | #REXX | REXX | /*REXX program displays the sequence (and/or lengths) for the look and say series.*/
parse arg N ! . /*obtain optional arguments from the CL*/
if N=='' | N=="," then N= 20 /*Not specified? Then use the default.*/
if !=='' | !=="," then != 1 ... | Give a code snippet in #REXX
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Text | Hello world/Text | Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
| #Elixir | Elixir |
IO.puts "Hello world!"
| Give a code snippet in #Elixir
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Egyptian_division | Egyptian division | Egyptian division is a method of dividing integers using addition and
doubling that is similar to the algorithm of Ethiopian multiplication
Algorithm:
Given two numbers where the dividend is to be divided by the divisor:
Start the construction of a table of two columns: powers_of_2, and doublings; by a first row of... | #Prolog | Prolog | egyptian_divide(Dividend, Divisor, Quotient, Remainder):-
powers2_multiples(Dividend, [1], Powers, [Divisor], Multiples),
accumulate(Dividend, Powers, Multiples, 0, Quotient, 0, Acc),
Remainder is Dividend - Acc.
powers2_multiples(Dividend, Powers, Powers, Multiples, Multiples):-
Multiples = [M|_],
... | Give a code snippet in #Prolog
Egyptian division is a method of dividing integers using addition and
doubling that is similar to the algorithm of Ethiopian multiplication
Algorithm:
Given two numbers where the dividend is to be divided by the divisor:
Start the construction of a table of two columns: powers_of_2, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compare_length_of_two_strings | Compare length of two strings |
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 |... | #Z80_Assembly | Z80 Assembly | Terminator equ 0 ;null terminator
PrintChar equ &BB5A ;Amstrad CPC BIOS call, prints accumulator to screen as an ASCII character.
org &8000
ld hl,String1
ld de,String2
call CompareStringLengths
jp nc, Print_HL_First
ex de,hl
Print_HL_First:
push bc
push hl
call PrintString
pop hl
pu... | Give a code snippet in #Z80_Assembly
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 Oper... | christopher/rosetta-code | |
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="heal... | #Nim | Nim | import sequtils, strutils
const LibXml = "libxml2.so"
type
XmlDocPtr = pointer
XmlXPathContextPtr = pointer
XmlElementKind = enum
xmlElementNode = 1
xmlAttributeNode = 2
xmlTextNode = 3
xmlCdataSectionNode = 4
xmlEntityRefNode = 5
xmlEntityNode = 6
xm... | Give a code snippet in #Nim
Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Merge_sort | Sorting algorithms/Merge sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program mergeSort.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see task include a file... | Give a code snippet in #ARM_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 |
Q... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Proper_divisors | Proper divisors | The proper divisors of a positive integer N are those numbers, other than N itself, that divide N without remainder.
For N > 1 they will always include 1, but for N == 1 there are no proper divisors.
Examples
The proper divisors of 6 are 1, 2, and 3.
The proper divisors of 100 are 1, 2, 4, 5... | #Oforth | Oforth | Integer method: properDivs self 2 / seq filter(#[ self swap mod 0 == ]) }
10 seq apply(#[ dup print " : " print properDivs println ])
20000 seq map(#[ dup properDivs size Pair new ]) reduce(#maxKey) println | Give a code snippet in #Oforth
The proper divisors of a positive integer N are those numbers, other than N itself, that divide N without remainder.
For N > 1 they will always include 1, but for N == 1 there are no proper divisors.
Examples
The proper divisors of 6 are 1, 2, and 3.
The proper divi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Start_from_a_main_routine | Start from a main routine |
Some languages (like Gambas and Visual Basic) support two startup modes. Applications written in these languages start with an open window that waits for events, and it is necessary to do some trickery to cause a main procedure to run instead. Data driven or event driven languages may also require similar tricker... | #Racket | Racket |
#/usr/bin/env racket -tm
#lang racket
(provide main)
(define (main . args) (displayln "Hello World!"))
| Give a code snippet in #Racket
Some languages (like Gambas and Visual Basic) support two startup modes. Applications written in these languages start with an open window that waits for events, and it is necessary to do some trickery to cause a main procedure to run instead. Data driven or event driven languages ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compound_data_type | Compound data type |
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.
Task
Create a compound data type:
Point(x,y)
A compound data type is one that holds multiple independent values.
Related task
Enumeration
S... | #ALGOL_W | ALGOL W | begin
% create the compound data type %
record Point( real x, y );
% declare a Point variable %
reference(Point) p;
% assign a value to p %
p := Point( 1, 0.5 );
% access the fields of p - note Algol W uses x(p) where many languages would use p.x %
write( x(p), y(p) )
end. | Give a code snippet in #ALGOL_W
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.
Task
Create a compound data type:
Point(x,y)
A compound data type is one that holds multiple independent values.
... | 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... | #EchoLisp | EchoLisp |
(lib 'math) ;; for (number->list) = explode function
(lib 'list) ;; (group)
(define (next L)
(for/fold (acc null) ((g (group L)))
(append acc (list (length g) (first g)))))
(define (task n starter)
(for/fold (L (number->list starter)) ((i n))
(writeln (list->string L))
(next L)))
| Give a code snippet in #EchoLisp
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 seque... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Constrained_random_points_on_a_circle | Constrained random points on a circle | Task
Generate 100 <x,y> coordinate pairs such that x and y are integers sampled from the uniform distribution with the condition that
10
≤
x
2
+
y
2
≤
15
{\displaystyle 10\leq {\sqrt {x^{2}+y^{2}}}\leq 15}
.
Then display/plot them. The outcome should be a "fuzzy" circle. The actual number of point... | #Frink | Frink | g = new graphics
count = 0
do
{
x = random[-15,15]
y = random[-15,15]
r = sqrt[x^2 + y^2]
if 10 <= r and r <= 15
{
count = count + 1
g.fillEllipseCenter[x,y,.3, .3]
}
} while count < 100
g.show[] | Give a code snippet in #Frink
Task
Generate 100 <x,y> coordinate pairs such that x and y are integers sampled from the uniform distribution with the condition that
10
≤
x
2
+
y
2
≤
15
{\displaystyle 10\leq {\sqrt {x^{2}+y^{2}}}\leq 15}
.
Then display/plot them. The outcome should be a "fuzzy" cir... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Window_creation | Window creation | Display a GUI window. The window need not have any contents, but should respond to requests to be closed.
| #Python | Python | import Tkinter
w = Tkinter.Tk()
w.mainloop() | Give a code snippet in #Python
Display a GUI window. The window need not have any contents, but should respond to requests to be closed.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/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 ... | #Common_Lisp | Common Lisp | (if (= val 42)
"That is the answer to life, the universe and everything"
"Try again") ; the else clause here is optional | Give a code snippet in #Common_Lisp
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.
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Teacup_rim_text | Teacup rim text | On a set of coasters we have, there's a picture of a teacup. On the rim of the teacup the word TEA appears a number of times separated by bullet characters (•).
It occurred to me that if the bullet were removed and the words run together, you could start at any letter and still end up with a meaningful three... | #Perl | Perl | use strict;
use warnings;
use feature 'say';
use List::Util qw(uniqstr any);
my(%words,@teacups,%seen);
open my $fh, '<', 'ref/wordlist.10000';
while (<$fh>) {
chomp(my $w = uc $_);
next if length $w < 3;
push @{$words{join '', sort split //, $w}}, $w;}
for my $these (values %words) {
next if @$th... | Give a code snippet in #Perl
On a set of coasters we have, there's a picture of a teacup. On the rim of the teacup the word TEA appears a number of times separated by bullet characters (•).
It occurred to me that if the bullet were removed and the words run together, you could start at any letter and still ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Numerical_integration/Gauss-Legendre_Quadrature | Numerical integration/Gauss-Legendre Quadrature |
In a general Gaussian quadrature rule, an definite integral of
f
(
x
)
{\displaystyle f(x)}
is first approximated over the interval
[
−
1
,
1
]
{\displaystyle [-1,1]}
by a polynomial approximable function
g
(
x
)
{\displaystyle g(x)}
and a known weighting function
W
(
x
)
{\displaystyle ... | #C | C | #include <stdio.h>
#include <math.h>
#define N 5
double Pi;
double lroots[N];
double weight[N];
double lcoef[N + 1][N + 1] = {{0}};
void lege_coef()
{
int n, i;
lcoef[0][0] = lcoef[1][1] = 1;
for (n = 2; n <= N; n++) {
lcoef[n][0] = -(n - 1) * lcoef[n - 2][0] / n;
for (i = 1; i <= n; i++)
lcoef[n][i] = ((... | Give a code snippet in #C
In a general Gaussian quadrature rule, an definite integral of
f
(
x
)
{\displaystyle f(x)}
is first approximated over the interval
[
−
1
,
1
]
{\displaystyle [-1,1]}
by a polynomial approximable function
g
(
x
)
{\displaystyle g(x)}
and a known weighting function
... | christopher/rosetta-code |
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