task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k |
|---|---|---|---|---|---|
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #Oz | Oz | {System.showInfo {Reverse "!dlroW olleH"}} |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #Pascal | Pascal | program RandomNumberDevice;
var
byteFile: file of byte;
randomByte: byte;
begin
assign(byteFile, '/dev/urandom');
reset (byteFile);
read (byteFile, randomByte);
close (byteFile);
writeln('The random byte is: ', randomByte);
end.
|
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #Perl | Perl | use Crypt::Random::Seed;
my $source = Crypt::Random::Seed->new( NonBlocking => 1 ); # Allow non-blocking sources like /dev/urandom
print "$_\n" for $source->random_values(10); # A method returning an array of 32-bit values |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #Phix | Phix | integer res -- 1=failure, 0=success
atom rint = 0 -- random 32-bit int
#ilASM{
mov eax,1
cpuid
bt ecx,30
mov edi,1 -- exit code: failure
jnc :exit
-- rdrand sets CF=0 if no random number
-- was available. Intel documentation
-- recommends 10 retries... |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #Julia | Julia | using Random
shufflerows(mat) = mat[shuffle(1:end), :]
shufflecols(mat) = mat[:, shuffle(1:end)]
function addatdiagonal(mat)
n = size(mat)[1] + 1
newmat = similar(mat, size(mat) .+ 1)
for j in 1:n, i in 1:n
newmat[i, j] = (i == n && j < n) ? mat[1, j] : (i == j) ? n - 1 :
(i < j) ? m... |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #Kotlin | Kotlin | typealias matrix = MutableList<MutableList<Int>>
fun printSquare(latin: matrix) {
for (row in latin) {
println(row)
}
println()
}
fun latinSquare(n: Int) {
if (n <= 0) {
println("[]")
return
}
val latin = MutableList(n) { MutableList(n) { it } }
// first row
... |
http://rosettacode.org/wiki/Ray-casting_algorithm | Ray-casting algorithm |
This page uses content from Wikipedia. The original article was at Point_in_polygon. 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)
Given a point and a polygon, check if the point is inside or out... | #R | R | point_in_polygon <- function(polygon, p) {
count <- 0
for(side in polygon) {
if ( ray_intersect_segment(p, side) ) {
count <- count + 1
}
}
if ( count %% 2 == 1 )
"INSIDE"
else
"OUTSIDE"
}
ray_intersect_segment <- function(p, side) {
eps <- 0.0001
a <- side$A
b <- side$B
if ( a... |
http://rosettacode.org/wiki/Queue/Definition | Queue/Definition |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operation... | #Action.21 | Action! | DEFINE MAXSIZE="200"
BYTE ARRAY queue(MAXSIZE)
BYTE queueFront=[0],queueRear=[0]
BYTE FUNC IsEmpty()
IF queueFront=queueRear THEN
RETURN (1)
FI
RETURN (0)
PROC Push(BYTE v)
BYTE rear
rear=queueRear+1
IF rear=MAXSIZE THEN
rear=0
FI
IF rear=queueFront THEN
PrintE("Error: queue is full!")
... |
http://rosettacode.org/wiki/Quaternion_type | Quaternion type | Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
wher... | #Action.21 | Action! | INCLUDE "H6:REALMATH.ACT"
DEFINE A_="+0"
DEFINE B_="+6"
DEFINE C_="+12"
DEFINE D_="+18"
TYPE Quaternion=[CARD a1,a2,a3,b1,b2,b3,c1,c2,c3,d1,d2,d3]
REAL neg
PROC Init()
ValR("-1",neg)
RETURN
BYTE FUNC Positive(REAL POINTER x)
BYTE ARRAY tmp
tmp=x
IF (tmp(0)&$80)=$00 THEN
RETURN (1)
FI
RETURN (0)
... |
http://rosettacode.org/wiki/Quine | Quine | A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program ... | #ALGOL_68 | ALGOL 68 | STRINGa="STRINGa=,q=REPR34;print(a[:8]+q+a+q+a[9:])",q=REPR34;print(a[:8]+q+a+q+a[9:]) |
http://rosettacode.org/wiki/Queue/Usage | Queue/Usage |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Ope... | #BBC_BASIC | BBC BASIC | FIFOSIZE = 1000
FOR n = 3 TO 5
PRINT "Push ";n : PROCenqueue(n)
NEXT
PRINT "Pop " ; FNdequeue
PRINT "Push 6" : PROCenqueue(6)
REPEAT
PRINT "Pop " ; FNdequeue
UNTIL FNisempty
PRINT "Pop " ; FNdequeue
END
DEF PROCenqueue(n) : LOCAL f%
D... |
http://rosettacode.org/wiki/Queue/Usage | Queue/Usage |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Ope... | #Bracmat | Bracmat | ( queue
= (list=)
(enqueue=.(.!arg) !(its.list):?(its.list))
( dequeue
= x
. !(its.list):?(its.list) (.?x)
& !x
)
(empty=.!(its.list):)
)
& new$queue:?Q
& ( (Q..enqueue)$1
& (Q..enqueue)$2
& (Q..enqueue)$3
& out$((Q..dequeue)$)
& (Q..enqueue)... |
http://rosettacode.org/wiki/Read_a_specific_line_from_a_file | Read a specific line from a file | Some languages have special semantics for obtaining a known line number from a file.
Task
Demonstrate how to obtain the contents of a specific line within a file.
For the purpose of this task demonstrate how the contents of the seventh line of a file can be obtained, and store it in a variable or in memory (fo... | #REXX | REXX | /*REXX program reads a specific line from a file (and displays the length and content).*/
parse arg FID n . /*obtain optional arguments from the CL*/
if FID=='' | FID=="," then FID= 'JUNK.TXT' /*not specified? Then use the default.*/
if n=='' | n=="," then n=7 ... |
http://rosettacode.org/wiki/Quickselect_algorithm | Quickselect algorithm |
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.23 | C# | // ----------------------------------------------------------------------------------------------
//
// Program.cs - QuickSelect
//
// ----------------------------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
namespace Quic... |
http://rosettacode.org/wiki/Ramer-Douglas-Peucker_line_simplification | Ramer-Douglas-Peucker line simplification | Ramer-Douglas-Peucker line simplification
You are encouraged to solve this task according to the task description, using any language you may know.
The Ramer–Douglas–Peucker algorithm is a line simplification algorithm for reducing the number of points used to define its shape.
Task
Using the Ramer–Douglas–P... | #Nim | Nim | import math
type
Point = tuple[x, y: float64]
proc pointLineDistance(pt, lineStart, lineEnd: Point): float64 =
var n, d, dx, dy: float64
dx = lineEnd.x - lineStart.x
dy = lineEnd.y - lineStart.y
n = abs(dx * (lineStart.y - pt.y) - (lineStart.x - pt.x) * dy)
d = sqrt(dx * dx + dy * dy)
n / d
proc rdp... |
http://rosettacode.org/wiki/Range_extraction | Range extraction | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #COBOL | COBOL | IDENTIFICATION DIVISION.
PROGRAM-ID. extract-range-task.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 data-str PIC X(200) VALUE "0, 1, 2, 4, 6,"
& " 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, "
& "24, 25, 27, 28, 29, 30, 31, 32, 33... |
http://rosettacode.org/wiki/Random_numbers | Random numbers | Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
| #Euphoria | Euphoria | include misc.e
function RandomNormal()
atom x1, x2
x1 = rand(999999) / 1000000
x2 = rand(999999) / 1000000
return sqrt(-2*log(x1)) * cos(2*PI*x2)
end function
constant n = 1000
sequence s
s = repeat(0,n)
for i = 1 to n do
s[i] = 1 + 0.5 * RandomNormal()
end for |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Julia | Julia | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Kotlin | Kotlin | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Read_a_configuration_file | Read a configuration file | The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# pr... | #Gambas | Gambas | Public Sub Form_Open()
Dim fullname As String = Settings["fullname", "Foo Barber"] 'If fullname is empty then use the default "Foo Barber"
Dim favouritefruit As String = Settings["favouritefruit", "banana"]
Dim needspeeling As String = Settings["needspeling", True]
Dim seedsremoved As String = Settings["seedsremoved... |
http://rosettacode.org/wiki/Rare_numbers | Rare numbers | Definitions and restrictions
Rare numbers are positive integers n where:
n is expressed in base ten
r is the reverse of n (decimal digits)
n must be non-palindromic (n ≠ r)
(n+r) is the sum
(n-r) is the difference and must be positive
the sum and the ... | #REXX | REXX | /*REXX program calculates and displays a specified amount of rare numbers. */
numeric digits 20; w= digits() + digits() % 3 /*use enough dec. digs for calculations*/
parse arg many . /*obtain optional argument from the CL.*/
if many=='' | many=="," then many= 5 ... |
http://rosettacode.org/wiki/Range_expansion | Range expansion | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #Delphi | Delphi |
program Range_expansion;
{$APPTYPE CONSOLE}
uses
System.SysUtils;
const
input = '-6,-3--1,3-5,7-11,14,15,17-20';
var
r: TArray<Integer>;
last, i, n: Integer;
begin
for var part in input.Split([',']) do
begin
i := part.Substring(1).IndexOf('-');
if i = -1 then
begin
if not TrySt... |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Draco | Draco | \util.g
proc nonrec main() void:
/* first we need to declare a file buffer and an input channel */
file() infile;
channel input text in_ch;
/* a buffer to store the line in is also handy */
[256] char line;
word counter; /* to count the lines */
/* open the file, and exit if it fails */... |
http://rosettacode.org/wiki/Ranking_methods | Ranking methods |
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
... | #Perl | Perl | my %scores = (
'Solomon' => 44,
'Jason' => 42,
'Errol' => 42,
'Garry' => 41,
'Bernard' => 41,
'Barry' => 41,
'Stephen' => 39
);
sub tiers {
my(%s) = @_; my(%h);
push @{$h{$s{$_}}}, $_ for keys %s;
@{\%h}{reverse sort keys %h};
}
sub standard {
my(%s) = @_; my($res... |
http://rosettacode.org/wiki/Range_consolidation | Range consolidation | Define a range of numbers R, with bounds b0 and b1 covering all numbers between and including both bounds.
That range can be shown as:
[b0, b1]
or equally as:
[b1, b0]
Given two ranges, the act of consolidation between them compares the two ranges:
If one range covers all of the other then t... | #Yabasic | Yabasic | sub sort(tabla())
local items, i, t1, t2, s
items = arraysize(tabla(), 1)
repeat
s = true
for i = 1 to items-1
if tabla(i, 1) > tabla(i+1, 1) then
t1 = tabla(i, 1) : t2 = tabla(i, 2)
tabla(i, 1) = tabla(i + 1, 1) : tabla(i, 2) = tabla(i + 1, 2)... |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #PARI.2FGP | PARI/GP | reverse(s)=concat(Vecrev(s)) |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #PicoLisp | PicoLisp | : (in "/dev/urandom" (rd 4))
-> 2917110327 |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #PowerShell | PowerShell |
function Get-RandomInteger
{
Param
(
[Parameter(Mandatory=$false,
ValueFromPipeline=$true,
ValueFromPipelineByPropertyName=$true,
Position=0)]
[ValidateScript({$_ -ge 4})]
[int[]]
$InputObject = 64
)
Begin
... |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #M2000_Interpreter | M2000 Interpreter |
Module FastLatinSquare {
n=5
For k=1 To 2
latin()
Next
n=40
latin()
Sub latin()
Local i,a, a(1 To n), b, k
Profiler
flush
Print "latin square ";n;" by ";n
For i=1 To n
Push i
Next i
For i=1 To n div 2
Shiftback random(2, n)
Next i
a=[]
Push ! stack(a)
a=array(a) ' change a from st... |
http://rosettacode.org/wiki/Ray-casting_algorithm | Ray-casting algorithm |
This page uses content from Wikipedia. The original article was at Point_in_polygon. 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)
Given a point and a polygon, check if the point is inside or out... | #Racket | Racket |
#lang racket
(module pip racket
(require racket/contract)
(provide point)
(provide seg)
(provide (contract-out [point-in-polygon? (->
point?
list?
boolean?)]))
(str... |
http://rosettacode.org/wiki/Queue/Definition | Queue/Definition |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operation... | #Ada | Ada | generic
type Element_Type is private;
package Fifo is
type Fifo_Type is private;
procedure Push(List : in out Fifo_Type; Item : in Element_Type);
procedure Pop(List : in out Fifo_Type; Item : out Element_Type);
function Is_Empty(List : Fifo_Type) return Boolean;
Empty_Error : exception;
private
typ... |
http://rosettacode.org/wiki/Quaternion_type | Quaternion type | Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
wher... | #Ada | Ada | generic
type Real is digits <>;
package Quaternions is
type Quaternion is record
A, B, C, D : Real;
end record;
function "abs" (Left : Quaternion) return Real;
function Conj (Left : Quaternion) return Quaternion;
function "-" (Left : Quaternion) return Quaternion;
function "+" (Left, Right : ... |
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 ... | #APL | APL | 1⌽,⍨9⍴'''1⌽,⍨9⍴''' ⍝ Author: Nikolay Nikolov; Source: https://dfns.dyalog.com/n_quine.htm |
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... | #C | C | #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <sys/queue.h>
/* #include "fifolist.h" */
int main()
{
int i;
FIFOList head;
TAILQ_INIT(&head);
/* insert 20 integer values */
for(i=0; i < 20; i++) {
m_enqueue(i, &head);
}
/* dequeue and print */
while( m_dequeue(&i, ... |
http://rosettacode.org/wiki/Read_a_specific_line_from_a_file | Read a specific line from a file | Some languages have special semantics for obtaining a known line number from a file.
Task
Demonstrate how to obtain the contents of a specific line within a file.
For the purpose of this task demonstrate how the contents of the seventh line of a file can be obtained, and store it in a variable or in memory (fo... | #Ring | Ring |
fp = fopen("C:\Ring\ReadMe.txt","r")
n = 0
r = ""
while isstring(r)
while n < 8
r = fgetc(fp)
if r = char(10) n++ see nl
else see r ok
end
end
fclose(fp)
|
http://rosettacode.org/wiki/Quickselect_algorithm | Quickselect algorithm |
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++ | #include <algorithm>
#include <iostream>
int main() {
for (int i = 0; i < 10; i++) {
int a[] = {9, 8, 7, 6, 5, 0, 1, 2, 3, 4};
std::nth_element(a, a + i, a + sizeof(a)/sizeof(*a));
std::cout << a[i];
if (i < 9) std::cout << ", ";
}
std::cout << std::endl;
return 0;
} |
http://rosettacode.org/wiki/Ramer-Douglas-Peucker_line_simplification | Ramer-Douglas-Peucker line simplification | Ramer-Douglas-Peucker line simplification
You are encouraged to solve this task according to the task description, using any language you may know.
The Ramer–Douglas–Peucker algorithm is a line simplification algorithm for reducing the number of points used to define its shape.
Task
Using the Ramer–Douglas–P... | #Openscad | Openscad | function slice(a, v) = [ for (i = v) a[i] ];
// Find the distance from the point to the line
function perpendicular_distance(pt, start, end) =
let (
d = end - start,
dn = d / norm(d),
dp = pt - start,
// Dot-product of two vectors
ddot = dn * dp,
ds = dn * ddot
... |
http://rosettacode.org/wiki/Ramer-Douglas-Peucker_line_simplification | Ramer-Douglas-Peucker line simplification | Ramer-Douglas-Peucker line simplification
You are encouraged to solve this task according to the task description, using any language you may know.
The Ramer–Douglas–Peucker algorithm is a line simplification algorithm for reducing the number of points used to define its shape.
Task
Using the Ramer–Douglas–P... | #Perl | Perl | use strict;
use warnings;
use feature 'say';
use List::MoreUtils qw(firstidx minmax);
my $epsilon = 1;
sub norm {
my(@list) = @_;
my $sum;
$sum += $_**2 for @list;
sqrt($sum)
}
sub perpendicular_distance {
our(@start,@end,@point);
local(*start,*end,*point) = (shift, shift, shift);
retu... |
http://rosettacode.org/wiki/Range_extraction | Range extraction | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #Common_Lisp | Common Lisp | (defun format-with-ranges (list)
(unless list (return ""))
(with-output-to-string (s)
(let ((current (first list))
(list (rest list))
(count 1))
(princ current s)
(dolist (next list)
(if (= next (1+ current))
(incf count)
(progn (princ (if (> ... |
http://rosettacode.org/wiki/Random_numbers | Random numbers | Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
| #F.23 | F# |
let n = MathNet.Numerics.Distributions.Normal(1.0,0.5)
List.init 1000 (fun _->n.Sample())
|
http://rosettacode.org/wiki/Random_numbers | Random numbers | Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
| #Factor | Factor | USING: random ;
1000 [ 1.0 0.5 normal-random-float ] replicate |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Lua | Lua | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #MATLAB | MATLAB | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Maxima | Maxima | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Read_a_configuration_file | Read a configuration file | The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# pr... | #Go | Go | package config
import (
"errors"
"io"
"fmt"
"bytes"
"strings"
"io/ioutil"
)
var (
ENONE = errors.New("Requested value does not exist")
EBADTYPE = errors.New("Requested type and actual type do not match")
EBADVAL = errors.New("Value and type do not match")
)
type varError struct {
err error
n stri... |
http://rosettacode.org/wiki/Rare_numbers | Rare numbers | Definitions and restrictions
Rare numbers are positive integers n where:
n is expressed in base ten
r is the reverse of n (decimal digits)
n must be non-palindromic (n ≠ r)
(n+r) is the sum
(n-r) is the difference and must be positive
the sum and the ... | #Ring | Ring |
load "stdlib.ring"
see "working..." + nl
see "the first 5 rare numbers are:" + nl
num = 0
for n = 1 to 2042832002
strn = string(n)
nrev = ""
for m = len(strn) to 1 step -1
nrev = nrev + strn[m]
next
nrev = number(nrev)
sum = n + nrev
diff = n - nrev
if diff < 1
loo... |
http://rosettacode.org/wiki/Range_expansion | Range expansion | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #DWScript | DWScript |
function ExpandRanges(ranges : String) : array of Integer;
begin
for var range in ranges.Split(',') do begin
var separator = range.IndexOf('-', 2);
if separator > 0 then begin
for var i := range.Left(separator-1).ToInteger to range.Copy(separator+1).ToInteger do
Result.Add(i);
... |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Elena | Elena | import system'io;
import extensions;
import extensions'routines;
public program()
{
File.assign:"file.txt".forEachLine(printingLn)
} |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Elixir | Elixir |
defmodule FileReader do
# Create a File.Stream and inspect each line
def by_line(path) do
File.stream!(path)
|> Stream.map(&(IO.inspect(&1)))
|> Stream.run
end
def bin_line(path) do
# Build the stream in binary instead for performance increase
case File.open(path) do
... |
http://rosettacode.org/wiki/Ranking_methods | Ranking methods |
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
... | #Phix | Phix | with javascript_semantics
function ties(sequence scores)
sequence t = {}, -- {start,num} pairs
tdx = repeat(0,length(scores))
integer last = -1
for i=1 to length(scores) do
integer curr = scores[i][1]
if curr=last then
t[$][2] += 1
else
t = append... |
http://rosettacode.org/wiki/Range_consolidation | Range consolidation | Define a range of numbers R, with bounds b0 and b1 covering all numbers between and including both bounds.
That range can be shown as:
[b0, b1]
or equally as:
[b1, b0]
Given two ranges, the act of consolidation between them compares the two ranges:
If one range covers all of the other then t... | #zkl | zkl | fcn consolidate(rs){
(s:=List()).append(
normalize(rs).reduce('wrap(ab,cd){
if(ab[1]>=cd[0]) L(ab[0],ab[1].max(cd[1])); // consolidate
else{ s.append(ab); cd } // no overlap
}) )
}
fcn normalize(s){ s.apply("sort").sort(fcn(a,b){ a[0]<b[0] }) } |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #Pascal | Pascal | { the result array must be at least as large as the original array }
procedure reverse(s: array[min .. max: integer] of char, var result: array[min1 .. max1: integer] of char);
var
i, len: integer;
begin
len := max-min+1;
for i := 0 to len-1 do
result[min1 + len-1 - i] := s[min + i]
end; |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #ProDOS | ProDOS | printline -random- |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #PureBasic | PureBasic | If OpenCryptRandom()
MyRandom = CryptRandom(#MAXLONG)
CloseCryptRandom()
EndIf |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #Python | Python | import random
rand = random.SystemRandom()
rand.randint(1,10) |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | Clear[RandomLatinSquare]
RandomLatinSquare[n_] := Module[{out, ord},
out = Table[RotateLeft[Range[n], i], {i, n}];
out = RandomSample[out];
ord = RandomSample[Range[n]];
out = out[[All, ord]];
out
]
RandomLatinSquare[5] // Grid |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #Nim | Nim | import random, sequtils, strutils
type LatinSquare = seq[seq[char]]
proc get[T](s: set[T]): T =
## Return the first element of a set.
for n in s:
return n
proc letterAt(n: Natural): char {.inline.} = chr(ord('A') - 1 + n)
proc latinSquare(n: Positive): LatinSquare =
result = newSeqWith(n, toSeq(lett... |
http://rosettacode.org/wiki/Ray-casting_algorithm | Ray-casting algorithm |
This page uses content from Wikipedia. The original article was at Point_in_polygon. 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)
Given a point and a polygon, check if the point is inside or out... | #Raku | Raku | constant ε = 0.0001;
sub ray-hits-seg([\Px,\Py], [[\Ax,\Ay], [\Bx,\By]] --> Bool) {
Py += ε if Py == Ay | By;
if Py < Ay or Py > By or Px > (Ax max Bx) {
False;
}
elsif Px < (Ax min Bx) {
True;
}
else {
my \red = Ax == Bx ?? Inf !! (By - Ay) / (Bx - Ax);
my \blue = Ax == Px ?? Inf !! (P... |
http://rosettacode.org/wiki/Queue/Definition | Queue/Definition |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operation... | #ALGOL_68 | ALGOL 68 | # -*- coding: utf-8 -*- #
CO REQUIRES:
MODE OBJLINK = STRUCT(
REF OBJLINK next,
REF OBJLINK prev,
OBJVALUE value # ... etc. required #
);
PROC obj link new = REF OBJLINK: ~;
PROC obj link free = (REF OBJLINK free)VOID: ~
END CO
# actually a pointer to the last LINK, there ITEMs are ADDED/get #
MOD... |
http://rosettacode.org/wiki/Quaternion_type | Quaternion type | Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
wher... | #ALGOL_68 | ALGOL 68 | # -*- coding: utf-8 -*- #
COMMENT REQUIRES:
MODE QUATSCAL = REAL; # Scalar #
QUATSCAL quat small scal = small real;
END COMMENT
# PROVIDES: #
FORMAT quat scal fmt := $g(-0, 4)$;
FORMAT signed fmt = $b("+", "")f(quat scal fmt)$;
FORMAT quat fmt = $f(quat scal fmt)"+"f(quat scal fmt)"i+"f(quat scal fmt)"j+"f(qu... |
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 ... | #Applesoft_BASIC | Applesoft BASIC | 10 LIST |
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... | #C.23 | C# | using System;
using System.Collections.Generic;
namespace RosettaCode
{
class Program
{
static void Main()
{
// Create a queue and "push" items into it
Queue<int> queue = new Queue<int>();
queue.Enqueue(1);
queue.Enqueue(3);
queue.En... |
http://rosettacode.org/wiki/Read_a_specific_line_from_a_file | Read a specific line from a file | Some languages have special semantics for obtaining a known line number from a file.
Task
Demonstrate how to obtain the contents of a specific line within a file.
For the purpose of this task demonstrate how the contents of the seventh line of a file can be obtained, and store it in a variable or in memory (fo... | #Ruby | Ruby | seventh_line = open("/etc/passwd").each_line.take(7).last
|
http://rosettacode.org/wiki/Read_a_specific_line_from_a_file | Read a specific line from a file | Some languages have special semantics for obtaining a known line number from a file.
Task
Demonstrate how to obtain the contents of a specific line within a file.
For the purpose of this task demonstrate how the contents of the seventh line of a file can be obtained, and store it in a variable or in memory (fo... | #Run_BASIC | Run BASIC | fileName$ = "f:\sample.txt"
requiredLine = 7
open fileName$ for input as #f
for i = 1 to requiredLine
if not(eof(#f)) then line input #f, a$
next i
close #f
print a$
end |
http://rosettacode.org/wiki/Quickselect_algorithm | Quickselect algorithm |
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
... | #CLU | CLU | quick = cluster [T: type] is select
where T has lt: proctype (T,T) returns (bool)
aT = array[T]
sT = sequence[T]
rep = null
swap = proc (list: aT, a, b: int)
temp: T := list[a]
list[a] := list[b]
list[b] := temp
end swap
partition = proc (list: aT, left, right... |
http://rosettacode.org/wiki/Ramer-Douglas-Peucker_line_simplification | Ramer-Douglas-Peucker line simplification | Ramer-Douglas-Peucker line simplification
You are encouraged to solve this task according to the task description, using any language you may know.
The Ramer–Douglas–Peucker algorithm is a line simplification algorithm for reducing the number of points used to define its shape.
Task
Using the Ramer–Douglas–P... | #Phix | Phix | with javascript_semantics
function rdp(sequence l, atom e)
if length(l)<2 then crash("not enough points to simplify") end if
integer idx := 0
atom dMax := -1,
{p1x,p1y} := l[1],
{p2x,p2y} := l[$],
x21 := p2x - p1x,
y21 := p2y - p1y
for i=1 to length(l) do
atom {px,py} = l[i],
... |
http://rosettacode.org/wiki/Range_extraction | Range extraction | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #D | D | import std.stdio, std.conv, std.string, std.algorithm, std.range;
string rangeExtraction(in int[] items)
in {
assert(items.isSorted);
} body {
if (items.empty)
return null;
auto ranges = [[items[0].text]];
foreach (immutable x, immutable y; items.zip(items[1 .. $]))
if (x + 1 == y)
... |
http://rosettacode.org/wiki/Random_numbers | Random numbers | Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
| #Falcon | Falcon | a = []
for i in [0:1000] : a+= norm_rand_num()
function norm_rand_num()
pi = 2*acos(0)
return 1 + (cos(2 * pi * random()) * pow(-2 * log(random()) ,1/2)) /2
end |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Modula-3 | Modula-3 | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Nanoquery | Nanoquery | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Nemerle | Nemerle | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #NetRexx | NetRexx | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Read_a_configuration_file | Read a configuration file | The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# pr... | #Groovy | Groovy | def config = [:]
def loadConfig = { File file ->
String regex = /^(;{0,1})\s*(\S+)\s*(.*)$/
file.eachLine { line ->
(line =~ regex).each { matcher, invert, key, value ->
if (key == '' || key.startsWith("#")) return
parts = value ? value.split(/\s*,\s*/) : (invert ? [false] : [tru... |
http://rosettacode.org/wiki/Rare_numbers | Rare numbers | Definitions and restrictions
Rare numbers are positive integers n where:
n is expressed in base ten
r is the reverse of n (decimal digits)
n must be non-palindromic (n ≠ r)
(n+r) is the sum
(n-r) is the difference and must be positive
the sum and the ... | #Ruby | Ruby | Term = Struct.new(:coeff, :ix1, :ix2) do
end
MAX_DIGITS = 16
def toLong(digits, reverse)
sum = 0
if reverse then
i = digits.length - 1
while i >=0
sum = sum *10 + digits[i]
i = i - 1
end
else
i = 0
while i < digits.length
sum =... |
http://rosettacode.org/wiki/Range_expansion | Range expansion | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #Dyalect | Dyalect | func main() {
let input = "-6,-3--1,3-5,7-11,14,15,17-20"
print("range: \(input)")
var r = []
var last = 0
for part in input.Split(',') {
var i = part[1..].IndexOf('-')
if i == -1 {
var n = Integer(part)
if r.Length() > 0 {
return print("dupli... |
http://rosettacode.org/wiki/Range_expansion | Range expansion | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #EchoLisp | EchoLisp |
;; parsing [spaces][-]digit(s)-[-]digit(s)[spaces]
(define R (make-regexp "^ *(\-?\\d+)\-(\-?\\d+) *$" ))
;; the native (range a b) is [a ... b[
;; (range+ a b) is [a ... b]
(define (range+ a b)
(if (< a b) (range a (1+ b))
(if (> a b) (range a (1- b) -1)
(list a))))
;; in : string : "number" or "number-number... |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Erlang | Erlang |
-module( read_a_file_line_by_line ).
-export( [into_list/1] ).
into_list( File ) ->
{ok, IO} = file:open( File, [read] ),
into_list( io:get_line(IO, ''), IO, [] ).
into_list( eof, _IO, Acc ) -> lists:reverse( Acc );
into_list( {error, _Error}, _IO, Acc ) -> lists:reverse( Acc );
into_list( Lin... |
http://rosettacode.org/wiki/Ranking_methods | Ranking methods |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #PowerShell | PowerShell |
function Get-Ranking
{
[CmdletBinding(DefaultParameterSetName="Standard")]
[OutputType([PSCustomObject])]
Param
(
[Parameter(Mandatory=$true,
ValueFromPipeline=$true,
ValueFromPipelineByPropertyName=$true,
Position=0)]
[string]
... |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #Peloton | Peloton | <# 显示 指定 变量 反转顺序 字串>集装箱|猫坐在垫子</#> |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #Racket | Racket |
#lang racket
;; Assuming a device to provide random bits:
(call-with-input-file* "/dev/random"
(λ(i) (integer-bytes->integer (read-bytes 4 i) #f)))
|
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #Raku | Raku | use experimental :pack;
my $UR = open("/dev/urandom", :bin) orelse .die;
my @random-spigot = $UR.read(1024).unpack("L*") ... *;
.say for @random-spigot[^10]; |
http://rosettacode.org/wiki/Random_number_generator_(device) | Random number generator (device) | Task
If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/urandom devices in Unix), then:
show how to obtain a random 32-bit number from that mechanism.
Related task
Random_number_generator_(included)
| #REXX | REXX | /*REXX program generates and displays a random 32-bit number using the RANDOM BIF.*/
numeric digits 10 /*ensure REXX has enough decimal digits*/
_=2**16 /*a handy─dandy constant to have around*/
r#= random(0, _-1) * _ + random(0, _-1) ... |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #Perl | Perl | use strict;
use warnings;
use feature 'say';
use List::Util 'shuffle';
sub random_ls {
my($n) = @_;
my(@cols,@symbols,@ls_sym);
# build n-sized latin square
my @ls = [0,];
for my $i (1..$n-1) {
@{$ls[$i]} = @{$ls[0]};
splice(@{$ls[$_]}, $_, 0, $i) for 0..$i;
}
# shuffle... |
http://rosettacode.org/wiki/Ray-casting_algorithm | Ray-casting algorithm |
This page uses content from Wikipedia. The original article was at Point_in_polygon. 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)
Given a point and a polygon, check if the point is inside or out... | #REXX | REXX | /*REXX program verifies if a horizontal ray from point P intersects a polygon. */
call points 5 5, 5 8, -10 5, 0 5, 10 5, 8 5, 10 10
A= 2.5; B= 7.5 /* ◄───── used for shorter arguments (below).*/
call poly 0 0, 10 0, 10 10, 0 10 ... |
http://rosettacode.org/wiki/Queue/Definition | Queue/Definition |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operation... | #ALGOL_W | ALGOL W | begin
% define a Queue type that will hold StringQueueElements %
record StringQueue ( reference(StringQueueElement) front, back );
% define the StringQueueElement type %
record StringQueueElement ( string(8) element
; reference(StringQueueElement) next
... |
http://rosettacode.org/wiki/Quaternion_type | Quaternion type | Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
wher... | #ALGOL_W | ALGOL W | begin
% Quaternion record type %
record Quaternion ( real a, b, c, d );
% returns the norm of the specified quaternion %
real procedure normQ ( reference(Quaternion) value q ) ;
sqrt( (a(q) * a(q)) + (b(q) * b(q)) + (c(q... |
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 ... | #Arturo | Arturo | block: [print ["block:" as .code block "do block"]] do block |
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... | #C.2B.2B | C++ | #include <queue>
#include <cassert> // for run time assertions
int main()
{
std::queue<int> q;
assert( q.empty() ); // initially the queue is empty
q.push(1); // add an element
assert( !q.empty() ); // now the queue isn't empty any more
assert( q.front() == 1 ); // the firs... |
http://rosettacode.org/wiki/Read_a_specific_line_from_a_file | Read a specific line from a file | Some languages have special semantics for obtaining a known line number from a file.
Task
Demonstrate how to obtain the contents of a specific line within a file.
For the purpose of this task demonstrate how the contents of the seventh line of a file can be obtained, and store it in a variable or in memory (fo... | #Rust | Rust | use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;
use std::io::Error;
use std::path::Path;
fn main() {
let path = Path::new("file.txt");
let line_num = 7usize;
let line = get_line_at(&path, line_num - 1);
println!("{}", line.unwrap());
}
fn get_line_at(path: &Path, line_num: usize) ->... |
http://rosettacode.org/wiki/Read_a_specific_line_from_a_file | Read a specific line from a file | Some languages have special semantics for obtaining a known line number from a file.
Task
Demonstrate how to obtain the contents of a specific line within a file.
For the purpose of this task demonstrate how the contents of the seventh line of a file can be obtained, and store it in a variable or in memory (fo... | #Scala | Scala | val lines = io.Source.fromFile("input.txt").getLines
val seventhLine = lines drop(6) next |
http://rosettacode.org/wiki/Quickselect_algorithm | Quickselect algorithm |
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
... | #COBOL | COBOL | CLASS-ID MainProgram.
METHOD-ID Partition STATIC USING T.
CONSTRAINTS.
CONSTRAIN T IMPLEMENTS type IComparable.
DATA DIVISION.
LOCAL-STORAGE SECTION.
01 pivot-val T.
PROCEDURE DIVISION USING VALUE arr AS T OCCURS ANY,
left-id... |
http://rosettacode.org/wiki/Ramer-Douglas-Peucker_line_simplification | Ramer-Douglas-Peucker line simplification | Ramer-Douglas-Peucker line simplification
You are encouraged to solve this task according to the task description, using any language you may know.
The Ramer–Douglas–Peucker algorithm is a line simplification algorithm for reducing the number of points used to define its shape.
Task
Using the Ramer–Douglas–P... | #PHP | PHP | function perpendicular_distance(array $pt, array $line) {
// Calculate the normalized delta x and y of the line.
$dx = $line[1][0] - $line[0][0];
$dy = $line[1][1] - $line[0][1];
$mag = sqrt($dx * $dx + $dy * $dy);
if ($mag > 0) {
$dx /= $mag;
$dy /= $mag;
}
// Calculate dot product, projecting ... |
http://rosettacode.org/wiki/Range_extraction | Range extraction | A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range s... | #Delphi | Delphi | procedure ExtractRanges(const values : array of Integer);
begin
var i:=0;
while i<values.Length do begin
if i>0 then
Print(',');
Print(values[i]);
var j:=i+1;
while (j<values.Length) and (values[j]=values[j-1]+1) do
Inc(j);
Dec(j);
if j>i then begin
i... |
http://rosettacode.org/wiki/Random_numbers | Random numbers | Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
| #Fantom | Fantom |
class Main
{
static const Float PI := 0.0f.acos * 2 // we need to precompute PI
static Float randomNormal ()
{
return (Float.random * PI * 2).cos * (Float.random.log * -2).sqrt
}
public static Void main ()
{
mean := 1.0f
sd := 0.5f
Float[] values := [,] // this is the collection to fi... |
http://rosettacode.org/wiki/Random_numbers | Random numbers | Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
| #Forth | Forth | require random.fs
here to seed
-1. 1 rshift 2constant MAX-D \ or s" MAX-D" ENVIRONMENT? drop
: frnd ( -- f ) \ uniform distribution 0..1
rnd rnd dabs d>f MAX-D d>f f/ ;
: frnd-normal ( -- f ) \ centered on 0, std dev 1
frnd pi f* 2e f* fcos
frnd fln -2e f* fsqrt f* ;
: ,normals ( n -- ) \ store many, ... |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Nim | Nim | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #OCaml | OCaml | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Octave | Octave | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Oz | Oz | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. |
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