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/Retrieve_and_search_chat_history | Retrieve and search chat history | Task
Summary: Find and print the mentions of a given string in the recent chat logs from a chatroom. Only use your programming language's standard library.
Details:
The Tcl Chatroom is an online chatroom. Its conversations are logged. It's useful to know if someone has mentioned you or your project in the chatroom r... | #Julia | Julia | using Dates, TimeZones, HTTP, Printf
function geturlbyday(n)
d = DateTime(now(tz"Europe/Berlin")) + Day(n) # n should be <= 0
uri = @sprintf("http://tclers.tk/conferences/tcl/%04d-%02d-%02d.tcl",
year(d), month(d), day(d))
return uri, String(HTTP.request("GET", uri).body)
end
function searchlog... | Give a code snippet in #Julia
Task
Summary: Find and print the mentions of a given string in the recent chat logs from a chatroom. Only use your programming language's standard library.
Details:
The Tcl Chatroom is an online chatroom. Its conversations are logged. It's useful to know if someone has mentioned you or... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_using_a_custom_comparator | Sort using a custom comparator |
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
... | #OCaml | OCaml | let mycmp s1 s2 =
if String.length s1 <> String.length s2 then
compare (String.length s2) (String.length s1)
else
String.compare (String.lowercase s1) (String.lowercase s2) | Give a code snippet in #OCaml
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/Sort_using_a_custom_comparator | Sort using a custom comparator |
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
... | #Kotlin | Kotlin | import java.util.Arrays
fun main(args: Array<String>) {
val strings = arrayOf("Here", "are", "some", "sample", "strings", "to", "be", "sorted")
fun printArray(message: String, array: Array<String>) = with(array) {
print("$message [")
forEachIndexed { index, string ->
print(if (in... | Give a code snippet in #Kotlin
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Letter_frequency | Letter frequency | Task
Open a text file and count the occurrences of each letter.
Some of these programs count all characters (including punctuation),
but some only count letters A to Z.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequen... | #Nim | Nim | import tables, os
var t = initCountTable[char]()
for l in paramStr(1).lines:
for c in l:
t.inc(c)
echo t | Give a code snippet in #Nim
Task
Open a text file and count the occurrences of each letter.
Some of these programs count all characters (including punctuation),
but some only count letters A to Z.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assig... | 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.
| #PureBasic | PureBasic | ;An array, map, or list can be used as a parameter to a procedure and in the
;process contain values to be returned as well.
Procedure example_1(x, y, Array r(1)) ;array r() will contain the return values
Dim r(2) ;clear and resize the array
r(0) = x + y ;return these values in the array
r(1) = x - y
r(2) = x... | Give a code snippet in #PureBasic
Task
Show how to return more than one value from a function.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Polymorphism | Polymorphism | Task
Create two classes Point(x,y) and Circle(x,y,r) with a polymorphic function print, accessors for (x,y,r), copy constructor, assignment and destructor and every possible default constructors
| #Scala | Scala | object PointCircle extends App {
class Point(x: Int = 0, y: Int = 0) {
def copy(x: Int = this.x, y: Int = this.y): Point = new Point(x, y)
override def toString = s"Point x: $x, y: $y"
}
object Point {
def apply(x: Int = 0, y: Int = 0): Point = new Point(x, y)
}
case class Circle(x: Int... | Give a code snippet in #Scala
Task
Create two classes Point(x,y) and Circle(x,y,r) with a polymorphic function print, accessors for (x,y,r), copy constructor, assignment and destructor and every possible default constructors
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/virtual_machine_interpreter | Compiler/virtual machine interpreter | A virtual machine implements a computer in software.
Task[edit]
Write a virtual machine interpreter. This interpreter should be able to run virtual
assembly language programs created via the task. This is a
byte-coded, 32-bit word stack based virtual machine.
The program should read input from a file and/or stdin, an... | #Aime | Aime | integer n, pc, sp;
file f;
text s;
index code, Data;
list l, stack, strings;
f.affix(argv(1));
f.list(l, 0);
n = atoi(l[-1]);
while (n) {
f.lead(s);
strings.append(erase(s, -1, 0));
n -= 1;
}
while (f.list(l, 0) ^ -1) {
code.put(atoi(lf_x_text(l)), l);
}
pc = sp = 0;
while (1) {
l = code[p... | Give a code snippet in #Aime
A virtual machine implements a computer in software.
Task[edit]
Write a virtual machine interpreter. This interpreter should be able to run virtual
assembly language programs created via the task. This is a
byte-coded, 32-bit word stack based virtual machine.
The program should read inpu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mouse_position | Mouse position | Task
Get the current location of the mouse cursor relative to the active window.
Please specify if the window may be externally created.
| #BBC_BASIC | BBC BASIC | MOUSE xmouse%, ymouse%, buttons%
PRINT xmouse%, ymouse% | Give a code snippet in #BBC_BASIC
Task
Get the current location of the mouse cursor relative to the active window.
Please specify if the window may be externally created.
| 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 ... | #CLU | CLU | weekday = proc (d: date) returns (int)
y: int := d.year
m: int := d.month
if m<3
then y, m := y-1, m+10
else m := m-2
end
c: int := y/100
y := y//100
z: int := (26*m-2)/10 + d.day + y + y/4 + c/4 - 2*c + 777
return(z//7)
end weekday
start_up = proc ()
po: stream :=... | Give a code snippet in #CLU
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 20... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #Perl | Perl | use utf8;
binmode STDOUT, ":utf8";
# to reverse characters (code points):
print reverse('visor'), "\n";
# to reverse graphemes:
print join("", reverse "José" =~ /\X/g), "\n";
$string = 'ℵΑΩ 駱駝道 🤔 🇸🇧 🇺🇸 🇬🇧 👨👩👧👦🆗🗺';
print join("", reverse $string =~ /\X/g), "\n"; | Give a code snippet in #Perl
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Narcissist | Narcissist | Quoting from the Esolangs wiki page:
A narcissist (or Narcissus program) is the decision-problem version of a quine.
A quine, when run, takes no input, but produces a copy of its own source code at its output. In contrast, a narcissist reads a string of symbols from its input, and produces no output except a "1" o... | #Rust | Rust | use std::io::{stdin, prelude::*};
fn main() {
let src = include_str!("main.rs");
let mut input = String::new();
stdin()
.lock()
.read_to_string(&mut input)
.expect("Could not read from STDIN");
println!("{}", src == input);
} | Give a code snippet in #Rust
Quoting from the Esolangs wiki page:
A narcissist (or Narcissus program) is the decision-problem version of a quine.
A quine, when run, takes no input, but produces a copy of its own source code at its output. In contrast, a narcissist reads a string of symbols from its input, and pro... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Taxicab_numbers | Taxicab numbers |
A taxicab number (the definition that is being used here) is a positive integer that can be expressed as the sum of two positive cubes in more than one way.
The first taxicab number is 1729, which is:
13 + 123 and also
93 + 103.
Taxicab numbers are also known as:
taxi numbers
tax... | #Wren | Wren | import "/sort" for Sort
import "/fmt" for Fmt
var cubesSum = {}
var taxicabs = []
for (i in 1..1199) {
for (j in i+1..1200) {
var sum = i*i*i + j*j*j
if (!cubesSum[sum]) {
cubesSum[sum] = [i, j]
} else {
taxicabs.add([sum, cubesSum[sum], [i, j]])
}
}
}... | Give a code snippet in #Wren
A taxicab number (the definition that is being used here) is a positive integer that can be expressed as the sum of two positive cubes in more than one way.
The first taxicab number is 1729, which is:
13 + 123 and also
93 + 103.
Taxicab numbers are also kno... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sockets | Sockets | For this exercise a program is open a socket to localhost on port 256 and send the message "hello socket world" before closing the socket.
Catching any exceptions or errors is not required.
| #Myrddin | Myrddin | use std
const main = {
match std.dial("tcp!localhost!256")
| `std.Ok fd:
std.write(fd, "hello socket world")
std.close(fd)
| `std.Err err:
std.fatal("could not open fd: {}\n", err)
;;
} | Give a code snippet in #Myrddin
For this exercise a program is open a socket to localhost on port 256 and send the message "hello socket world" before closing the socket.
Catching any exceptions or errors is not required.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #XPL0 | XPL0 | string 0; \use zero-terminated string convention
code Text=12;
func StrLen(A); \Return number of characters in an ASCIIZ string
char A;
int I;
for I:= 0 to -1>>1-1 do
if A(I) = 0 then return I;
proc IncStr(S); \Increment a numeric string
char S;
int I;
[for I:= StrLen(S)-1 do... | Give a code snippet in #XPL0
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Church_numerals | Church numerals | Task
In the Church encoding of natural numbers, the number N is encoded by a function that applies its first argument N times to its second argument.
Church zero always returns the identity function, regardless of its first argument. In other words, the first argument is not applied to the second argument at all.
C... | #Perl | Perl | use 5.020;
use feature qw<signatures>;
no warnings qw<experimental::signatures>;
use constant zero => sub ($f) {
sub ($x) { $x }};
use constant succ => sub ($n) {
sub ($f) {
sub ($x) { $f->($n->($f)($x)) }}};
use constant add => sub ($n) {
... | Give a code snippet in #Perl
Task
In the Church encoding of natural numbers, the number N is encoded by a function that applies its first argument N times to its second argument.
Church zero always returns the identity function, regardless of its first argument. In other words, the first argument is not applied to ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Reverse_words_in_a_string | Reverse words in a string | Task
Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified.
Example
Hey you, Bub! would be shown reversed as: Bub! you, Hey
Tokens are any non-space characters separated by spaces (formally, white-space); t... | #Wren | Wren | var lines = [
"---------- Ice and Fire ------------",
" ",
"fire, in end will world the say Some",
"ice. in say Some ",
"desire of tasted I've what From ",
"fire. favor who those with hold I ",
" ... | Give a code snippet in #Wren
Task
Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified.
Example
Hey you, Bub! would be shown reversed as: Bub! you, Hey
Tokens are any non-space characters separated by space... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_file_character_by_character/UTF8 | Read a file character by character/UTF8 | Task
Read a file one character at a time, as opposed to reading the entire file at once.
The solution may be implemented as a procedure, which returns the next character in the file on each consecutive call (returning EOF when the end of the file is reached).
The procedure should support the reading of files contain... | #zkl | zkl | fcn readUTF8c(chr,s=""){ // transform UTF-8 character stream
s+=chr;
try{ s.len(8); return(s) }
catch{ if(s.len()>6) throw(__exception) } // 6 bytes max for UTF-8
return(Void.Again,s); // call me again with s & another character
} | Give a code snippet in #zkl
Task
Read a file one character at a time, as opposed to reading the entire file at once.
The solution may be implemented as a procedure, which returns the next character in the file on each consecutive call (returning EOF when the end of the file is reached).
The procedure should support... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dot_product | Dot product | Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1]
If implementing the dot ... | #MUMPS | MUMPS | DOTPROD(A,B)
;Returns the dot product of two vectors. Vectors are assumed to be stored as caret-delimited strings of numbers.
;If the vectors are not of equal length, a null string is returned.
QUIT:$LENGTH(A,"^")'=$LENGTH(B,"^") ""
NEW I,SUM
SET SUM=0
FOR I=1:1:$LENGTH(A,"^") SET SUM=SUM+($PIECE(A,"^",I)*$PIECE(... | Give a code snippet in #MUMPS
Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ackermann_function | Ackermann function | The Ackermann function is a classic example of a recursive function, notable especially because it is not a primitive recursive function. It grows very quickly in value, as does the size of its call tree.
The Ackermann function is usually defined as follows:
A
(
m
,
n
)
=
{
n
+
1
if
m
=
0
A
(
m
... | #WDTE | WDTE | let memo a m n => true {
== m 0 => + n 1;
== n 0 => a (- m 1) 1;
true => a (- m 1) (a m (- n 1));
}; | Give a code snippet in #WDTE
The Ackermann function is a classic example of a recursive function, notable especially because it is not a primitive recursive function. It grows very quickly in value, as does the size of its call tree.
The Ackermann function is usually defined as follows:
A
(
m
,
n
)
=
{
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Numerical_integration | Numerical integration | Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods:
rectangular
left
right
midpoint
trapezium
Simpson's
composite
Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n).
Assume t... | #PicoLisp | PicoLisp | (scl 6)
(de leftRect (Fun X)
(Fun X) )
(de rightRect (Fun X H)
(Fun (+ X H)) )
(de midRect (Fun X H)
(Fun (+ X (/ H 2))) )
(de trapezium (Fun X H)
(/ (+ (Fun X) (Fun (+ X H))) 2) )
(de simpson (Fun X H)
(*/
(+
(Fun X)
(* 4 (Fun (+ X (/ H 2))))
(Fun (+ X H)) )
... | Give a code snippet in #PicoLisp
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods:
rectangular
left
right
midpoint
trapezium
Simpson's
composite
Your functions should take in the upper and lower bounds (a and b), and the number of approximations to... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Binary_search | Binary search | A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret number, and will only tell the p... | #APL | APL | binsrch←{
⎕IO(⍺{ ⍝ first lower bound is start of array
⍵<⍺:⍬ ⍝ if high < low, we didn't find it
mid←⌊(⍺+⍵)÷2 ⍝ calculate mid point
⍺⍺[mid]>⍵⍵:⍺∇mid-1 ⍝ if too high, search from ⍺ to mid-1
⍺⍺[mid]<⍵⍵:(mid+1)∇⍵ ⍝ if too low, sea... | Give a code snippet in #APL
A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret num... | 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... | #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
Function isPangram(s As Const String) As Boolean
Dim As Integer length = Len(s)
If length < 26 Then Return False
Dim p As String = LCase(s)
For i As Integer = 97 To 122
If Instr(p, Chr(i)) = 0 Then Return False
Next
Return True
End Function
Dim s(1 To 3) As String = _
{ _
"The qui... | Give a code snippet in #FreeBASIC
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Operator_precedence | Operator precedence |
This page uses content from Wikipedia. The original article was at Operators in C and C++. 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)
Task
Provide a list of precedence and associativity... | #Clojure | Clojure | : \ ? = ~ / ! # $ % & * + - < > @ ^ ` | , ' ; | Give a code snippet in #Clojure
This page uses content from Wikipedia. The original article was at Operators in C and C++. 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)
Task
Provide a list of ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Plot_coordinate_pairs | Plot coordinate pairs | Task
Plot a function represented as x, y numerical arrays.
Post the resulting image for the following input arrays (taken from Python's Example section on Time a function):
x = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
y = {2.7, 2.8, 31.4, 38.1, 58.0, 76.2, 100.5, 130.0, 149.... | #R | R | x <- c(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
y <- c(2.7, 2.8, 31.4, 38.1, 58.0, 76.2, 100.5, 130.0, 149.3, 180.0) | Give a code snippet in #R
Task
Plot a function represented as x, y numerical arrays.
Post the resulting image for the following input arrays (taken from Python's Example section on Time a function):
x = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
y = {2.7, 2.8, 31.4, 38.1, 58.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Primality_by_trial_division | Primality by trial division | Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other loops are allowed.
Related tasks
... | #Rust | Rust | fn is_prime(n: u64) -> bool {
match n {
0 | 1 => false,
2 => true,
_even if n % 2 == 0 => false,
_ => {
let sqrt_limit = (n as f64).sqrt() as u64;
(3..=sqrt_limit).step_by(2).find(|i| n % i == 0).is_none()
}
}
}
fn main() {
for i in (1..30).f... | Give a code snippet in #Rust
Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other loops ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Write_entire_file | Write entire file | Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| #Tcl | Tcl | proc writefile {filename data} {
set fd [open $filename w] ;# truncate if exists, else create
try {
puts -nonewline $fd $data
} finally {
close $fd
}
} | Give a code snippet in #Tcl
Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Check_Machin-like_formulas | Check Machin-like formulas | Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing they equal 1:
π
4
=
ar... | #Phix | Phix | with javascript_semantics
procedure test(atom a)
if -3*PI/4 >= a then ?9/0 end if
if 5*PI/4 <= a then ?9/0 end if
string s = sprint(tan(a))
?s -- or test for "1.0"/"1", but not 1.0
end procedure
test( arctan(1 / 2) + arctan(1 / 3))
test( 2*arctan(1 / 3) + arctan(1 / 7))
test( 4*arctan(... | Give a code snippet in #Phix
Machin-like formulas are useful for efficiently computing numerical approximations for
π
{\displaystyle \pi }
Task
Verify the following Machin-like formulas are correct by calculating the value of tan (right hand side) for each equation using exact arithmetic and showing th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Deconvolution/1D | Deconvolution/1D | The convolution of two functions
F
{\displaystyle {\mathit {F}}}
and
H
{\displaystyle {\mathit {H}}}
of
an integer variable is defined as the function
G
{\displaystyle {\mathit {G}}}
satisfying
G
(
n
)
=
∑
m
=
−
∞
∞
F
(
m
)
H
(
n
−
m
)
{\displaystyle G(n)=\sum _{m=-\inft... | #zkl | zkl | var [const] GSL=Import("zklGSL"); // libGSL (GNU Scientific Library)
fcn dconv1D(f,g){
fsz,hsz:=f.len(), g.len() - fsz +1;
A:=GSL.Matrix(g.len(),hsz);
foreach n,fn in ([0..].zip(f)){ foreach rc in (hsz){ A[rc+n,rc]=fn } }
h:=A.AxEQb(g);
h
} | Give a code snippet in #zkl
The convolution of two functions
F
{\displaystyle {\mathit {F}}}
and
H
{\displaystyle {\mathit {H}}}
of
an integer variable is defined as the function
G
{\displaystyle {\mathit {G}}}
satisfying
G
(
n
)
=
∑
m
=
−
∞
∞
F
(
m
)
H
(
n
−
m
)
{\disp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Runtime_evaluation/In_an_environment | Runtime evaluation/In an environment | x
x
x
Do so in a way which:
does not involve string manipulation of the input source code
is plausibly extensible to a runtime-chosen set of bindings rather than just x
does not make x a global variable
or note that these are impossible.
See also
For more general examples and language-specific details, see... | #Wren | Wren | import "meta" for Meta
var x
Meta.eval("x = 2")
System.print("First x = %(x)")
var y = x // save this value
Meta.eval("x = 5")
System.print("Second x = %(x)")
Meta.eval("x = x - y")
System.print("Delta x = %(x)") | Give a code snippet in #Wren
x
x
x
Do so in a way which:
does not involve string manipulation of the input source code
is plausibly extensible to a runtime-chosen set of bindings rather than just x
does not make x a global variable
or note that these are impossible.
See also
For more general examples and ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rename_a_file | Rename a file | Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the rights to do so.
(In unix-type s... | #Nim | Nim | import os
moveFile("input.txt", "output.txt")
moveFile("docs", "mydocs")
moveFile(DirSep & "input.txt", DirSep & "output.txt")
moveFile(DirSep & "docs", DirSep & "mydocs") | Give a code snippet in #Nim
Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the righ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Base64_decode_data | Base64 decode data | See Base64 encode data.
Now write a program that takes the output of the Base64 encode data task as input and regenerate the original file.
When working on the VBA implementation I found several 'solutions' on the net, including one from the software maker himself, that showed output with incorrect padding. Obviously... | #Forth | Forth | variable bitsbuff
: char>6bits ( c -- u )
dup 43 = if drop 62 exit then ( + case )
dup 47 = if drop 63 exit then ( / case )
dup 48 58 within if 48 - 52 + exit then ( 0-9 case )
dup 65 91 within if 65 - exit then ( A-Z case )
dup 97 123 within if 97 - 26 + exit t... | Give a code snippet in #Forth
See Base64 encode data.
Now write a program that takes the output of the Base64 encode data task as input and regenerate the original file.
When working on the VBA implementation I found several 'solutions' on the net, including one from the software maker himself, that showed output wi... | 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... | #Rascal | Rascal | import IO;
import util::Math;
str html(str title, str content) = item("html", item("title", title) + item("body", content));
str item(str op, str content) = "\<<op>\><content>\</<op>\>";
str table(str content) = item("table border=\"0\"", content);
str tr(str content) = item("tr", content);
str td(str content) = item... | Give a code snippet in #Rascal
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 wi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Date_manipulation | Date manipulation | Task
Given the date string "March 7 2009 7:30pm EST",
output the time 12 hours later in any human-readable format.
As extra credit, display the resulting time in a time zone different from your own.
| #Lingo | Lingo | ----------------------------------------
-- Returns string representation of given date object in YYYY-MM-DD hh:mm:ii format
-- @param {date} dateObj
-- @returns {string}
----------------------------------------
on dateToDateTimeString (dateObj)
str = ""
s = string(dateObj.year)
if s.length<4 then put "0000".char... | Give a code snippet in #Lingo
Task
Given the date string "March 7 2009 7:30pm EST",
output the time 12 hours later in any human-readable format.
As extra credit, display the resulting time in a time zone different from your own.
| 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 ... | #Java | Java | if(s.equals("Hello World"))
{
foo();
}
else if(s.equals("Bye World"))
bar();//{}'s optional for one-liners
else
{
deusEx();
} | Give a code snippet in #Java
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 c... | christopher/rosetta-code | |
http://rosettacode.org/wiki/HTTP | HTTP | Task
Access and print a URL's content (the located resource) to the console.
There is a separate task for HTTPS Requests.
| #Scala | Scala | import scala.io.Source
object HttpTest extends App {
System.setProperty("http.agent", "*")
Source.fromURL("http://www.rosettacode.org").getLines.foreach(println)
} | Give a code snippet in #Scala
Task
Access and print a URL's content (the located resource) to the console.
There is a separate task for HTTPS Requests.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Real_constants_and_functions | Real constants and functions | Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "magnitude")
floor (largest ... | #Frink | Frink |
e
pi, π // Unicode can also be written in ASCII programs as \u03C0
sqrt[x]
ln[x] // Natural log
log[x] // Log to base 10
exp[x], e^x
abs[x]
floor[x] // Except for complex numbers where there's no good interpretation.
ceil[x] // Except for complex numbers where there's no good interpretation.
x^y
| Give a code snippet in #Frink
Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "m... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Number_names | Number names | Task
Show how to spell out a number in English.
You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less).
Support for inputs other than positive integers (like zero, negat... | #MiniScript | MiniScript | singles = " one two three four five six seven eight nine ".split
teens = "ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen ".split
tys = " twenty thirty forty fifty sixty seventy eighty ninety".split
ions = "thousand million billion".split
numberName = function(n)
if n == 0 then re... | Give a code snippet in #MiniScript
Task
Show how to spell out a number in English.
You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less).
Support for inputs other than... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow ... | #Ruby | Ruby | def fib(n)
if n < 2
n
else
prev, fib = 0, 1
(n-1).times do
prev, fib = fib, fib + prev
end
fib
end
end
p (0..10).map { |i| fib(i) } | Give a code snippet in #Ruby
The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Narcissist | Narcissist | Quoting from the Esolangs wiki page:
A narcissist (or Narcissus program) is the decision-problem version of a quine.
A quine, when run, takes no input, but produces a copy of its own source code at its output. In contrast, a narcissist reads a string of symbols from its input, and produces no output except a "1" o... | #Java | Java | import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Narcissist {
private static final String SOURCE = "import java.io.BufferedReader;%nimport java.io.IOException;%nimport java.io.InputStreamReader;%n%npublic class Narcissist {%n private static final String ... | Give a code snippet in #Java
Quoting from the Esolangs wiki page:
A narcissist (or Narcissus program) is the decision-problem version of a quine.
A quine, when run, takes no input, but produces a copy of its own source code at its output. In contrast, a narcissist reads a string of symbols from its input, and pro... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Pancake_sort | Sorting algorithms/Pancake 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
... | #C.23 | C# |
public static class PancakeSorter
{
public static void Sort<T>(List<T> list) where T : IComparable
{
if (list.Count < 2)
{
return;
}
int i, a, max_num_pos;
for (i = list.Count; i > 1; i--)
{
max_num_pos = 0;
for (a = 0; a < i;... | Give a code snippet in #C.23
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sor... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #D | D | import std.stdio, std.algorithm, std.complex;
import std.math: PI;
auto radians(T)(in T d) pure nothrow @nogc { return d * PI / 180; }
auto degrees(T)(in T r) pure nothrow @nogc { return r * 180 / PI; }
real meanAngle(T)(in T[] D) pure nothrow @nogc {
immutable t = reduce!((a, d) => a + d.radians.expi)(0.comple... | Give a code snippet in #D
When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Greatest_element_of_a_list | Greatest element of a list | Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
| #JavaScript | JavaScript | Math.max.apply(null, [ 0, 1, 2, 5, 4 ]); // 5 | Give a code snippet in #JavaScript
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
| 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.
| #Stata | Stata | n=7
exp(2i*pi()/n*(0::n-1))
1
+-----------------------------+
1 | 1 |
2 | .623489802 + .781831482i |
3 | -.222520934 + .974927912i |
4 | -.900968868 + .433883739i |
5 | -.900968868 - .433883739i |
6 | -.222520934 - .974927912i |
7 | ... | Give a code snippet in #Stata
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/Assertions | Assertions | Assertions are a way of breaking out of code when there is an error or an unexpected input.
Some languages throw exceptions and some treat it as a break point.
Task
Show an assertion in your language by asserting that an integer variable is equal to 42.
| #Lingo | Lingo | -- in a movie script
on assert (ok, message)
if not ok then
if not voidP(message) then _player.alert(message)
abort -- exits from current call stack, i.e. also from the caller function
end if
end
-- anywhere in the code
on test
x = 42
assert(x=42, "Assertion 'x=42' failed")
put "this shows up"
x =... | Give a code snippet in #Lingo
Assertions are a way of breaking out of code when there is an error or an unexpected input.
Some languages throw exceptions and some treat it as a break point.
Task
Show an assertion in your language by asserting that an integer variable is equal to 42.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix-exponentiation_operator | Matrix-exponentiation operator | Most programming languages have a built-in implementation of exponentiation for integers and reals only.
Task
Demonstrate how to implement matrix exponentiation as an operator.
| #K | K |
/Matrix Exponentiation
/mpow.k
pow: {:[0=y; :({a=/:a:!x}(#x))];a: x; do[y-1; a: x _mul a]; :a}
| Give a code snippet in #K
Most programming languages have a built-in implementation of exponentiation for integers and reals only.
Task
Demonstrate how to implement matrix exponentiation as an operator.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/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... | #Rust | Rust | fn main() {
// Rust has a lot of neat things you can do with functions: let's go over the basics first
fn no_args() {}
// Run function with no arguments
no_args();
// Calling a function with fixed number of arguments.
// adds_one takes a 32-bit signed integer and returns a 32-bit signed intege... | Give a code snippet in #Rust
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 var... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pick_random_element | Pick random element | Demonstrate how to pick a random element from a list.
| #GW-BASIC | GW-BASIC | 10 RANDOMIZE TIMER : REM set random number seed to something arbitrary
20 DIM ARR(10) : REM initialise array
30 FOR I = 1 TO 10
40 ARR(I) = I*I : REM squares of the integers is OK as a demo
50 NEXT I
60 C = 1 + INT(RND*10) : REM get a random index from 1 to 10 inclusive
70 PRINT ARR(... | Give a code snippet in #GW-BASIC
Demonstrate how to pick a random element from a list.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #Befunge | Befunge | 55+~>:48>*#8\#4`#:!#<#~_$>:#,_@ | Give a code snippet in #Befunge
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
Emp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #Mirah | Mirah | empty_string1 = ""
empty_string2 = String.new
puts "empty string is empty" if empty_string1.isEmpty()
puts "empty string has no length" if empty_string2.length() == 0
puts "empty string is not nil" unless empty_string1 == nil | Give a code snippet in #Mirah
Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Oth... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dot_product | Dot product | Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1]
If implementing the dot ... | #PowerShell | PowerShell |
function dotproduct( $a, $b) {
$a | foreach -Begin {$i = $res = 0} -Process { $res += $_*$b[$i++] } -End{$res}
}
dotproduct (1..2) (1..2)
dotproduct (1..10) (11..20)
| Give a code snippet in #PowerShell
Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stirling_numbers_of_the_second_kind | Stirling numbers of the second kind | Stirling numbers of the second kind, or Stirling partition numbers, are the
number of ways to partition a set of n objects into k non-empty subsets. They are
closely related to Bell numbers, and may be derived from them.
Stirling numbers of the second kind obey the recurrence relation:
S2(n, 0) and S2(0, k) = 0 ... | #Phix | Phix | with javascript_semantics
include mpfr.e
constant lim = 100,
lim1 = lim+1,
last = 12
sequence s2 = repeat(0,lim1)
for n=1 to lim1 do
s2[n] = mpz_inits(lim1)
mpz_set_si(s2[n][n],1)
end for
mpz {t, m100} = mpz_inits(2)
for n=1 to lim do
for k=1 to n do
mpz_set_si(t,k)
mpz_... | Give a code snippet in #Phix
Stirling numbers of the second kind, or Stirling partition numbers, are the
number of ways to partition a set of n objects into k non-empty subsets. They are
closely related to Bell numbers, and may be derived from them.
Stirling numbers of the second kind obey the recurrence relation:
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows | Bulls and cows | Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the guess is the same as the random... | #Smart_BASIC | Smart BASIC |
'by rbytes, January 2017
OPTION BASE 1
P(" B U L L S A N D C O W S")!l
P("A secret 4-digit number has been created, with")
P("no repeats and no zeros. You must guess the number.")
P("After each guess, you will be shown how many of your")
P("digits are correct and in the matching location (bulls),")
P("and how m... | Give a code snippet in #Smart_BASIC
Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #gnuplot | gnuplot | # this is a comment
# backslash continues \
a comment to the next \
line or lines | Give a code snippet in #gnuplot
Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| 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... | #Lasso | Lasso | define printArgs(...items) => stdoutnl(#items)
define printEachArg(...) => with i in #rest do stdoutnl(#i)
printArgs('a', 2, (:3))
printEachArg('a', 2, (:3)) | Give a code snippet in #Lasso
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.
R... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic/Integer | Arithmetic/Integer |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #68000_Assembly | 68000 Assembly | ADD.L D0,D1 ; add two numbers
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
SUB.L D1,D0 ; subtract D1 from D0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
MULU D0,D1 ; multiply two unsigned numbers. Use MULS for signed numbers
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DIVU D1,D0 ; Divide D0 by D1. Use DIVS for signed numbers. Upper two bytes of D0 ar... | Give a code snippet in #68000_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 Op... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #WebAssembly | WebAssembly | (module
;;The entry point for WASI is called _start
(func $main (export "_start")
)
)
| Give a code snippet in #WebAssembly
Task
Create the simplest possible program that is still considered "correct."
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program caresarcode.s */
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
.equ STRINGSIZE, 500
/* Initialized data ... | Give a code snippet in #ARM_Assembly
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrappi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Primality_by_Wilson%27s_theorem | Primality by Wilson's theorem | Task
Write a boolean function that tells whether a given integer is prime using Wilson's theorem.
By Wilson's theorem, a number p is prime if and only if p divides (p - 1)! + 1.
Remember that 1 and all non-positive integers are not prime.
See also
Cut-the-knot: Wilson's theorem.
Wikipedia: Wilson's theorem
| #J | J |
wilson=: 0 = (| !&.:<:)
(#~ wilson) x: 2 + i. 30
2 3 5 7 11 13 17 19 23 29 31
| Give a code snippet in #J
Task
Write a boolean function that tells whether a given integer is prime using Wilson's theorem.
By Wilson's theorem, a number p is prime if and only if p divides (p - 1)! + 1.
Remember that 1 and all non-positive integers are not prime.
See also
Cut-the-knot: Wilson's theorem.
Wiki... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequ... | #Component_Pascal | Component Pascal |
MODULE CountOctal;
IMPORT StdLog,Strings;
PROCEDURE Do*;
VAR
i: INTEGER;
resp: ARRAY 32 OF CHAR;
BEGIN
FOR i := 0 TO 1000 DO
Strings.IntToStringForm(i,8,12,' ',TRUE,resp);
StdLog.String(resp);StdLog.Ln
END
END Do;
END CountOctal.
| Give a code snippet in #Component_Pascal
Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Tcl | Tcl | package require Tk
proc output_ppm {image filename} {
$image write $filename -format ppm
}
set img [newImage 150 150]
fill $img red
setPixel $img green 40 40
output_ppm $img filename.ppm
# check the file format:
set fh [open filename.ppm]
puts [gets $fh] ;# ==> P6
puts [gets $fh] ;# ==> 150 150
puts [gets $fh... | Give a code snippet in #Tcl
Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Image_noise | Image noise | Generate a random black and white 320x240 image continuously,
showing FPS (frames per second).
A sample image
| #Pascal | Pascal | Program ImageNoise;
uses
SDL;
var
surface: PSDL_Surface;
pixel: ^byte;
frameNumber, totalTime, lastTime, time, i: longint;
begin
frameNumber := 0;
totalTime := 0;
lastTime := 0;
randomize;
SDL_Init(SDL_INIT_TIMER or SDL_INIT_VIDEO);
surface := SDL_SetVideoMode(320, 240, 8, SDL_DOUBLEBUF o... | Give a code snippet in #Pascal
Generate a random black and white 320x240 image continuously,
showing FPS (frames per second).
A sample image
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Bioinformatics/Sequence_mutation | Bioinformatics/Sequence mutation | Task
Given a string of characters A, C, G, and T representing a DNA sequence write a routine to mutate the sequence, (string) by:
Choosing a random base position in the sequence.
Mutate the sequence by doing one of either:
Swap the base at that position by changing it to one of A, C, G, or T. (which has a chance o... | #Rust | Rust |
use rand::prelude::*;
use std::collections::HashMap;
use std::fmt::{Display, Formatter, Error};
pub struct Seq<'a> {
alphabet: Vec<&'a str>,
distr: rand::distributions::Uniform<usize>,
pos_distr: rand::distributions::Uniform<usize>,
seq: Vec<&'a str>,
}
impl Display for Seq<'_> {
fn fmt(&self,... | Give a code snippet in #Rust
Task
Given a string of characters A, C, G, and T representing a DNA sequence write a routine to mutate the sequence, (string) by:
Choosing a random base position in the sequence.
Mutate the sequence by doing one of either:
Swap the base at that position by changing it to one of A, C, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Smalltalk | Smalltalk | "Comments traditionally are in double quotes."
"Multiline comments are also supported.
Comments are saved as metadata along with the source to a method.
A comment just after a method signature is often given to explain the
usage of the method. The class browser may display such comments
specially." | Give a code snippet in #Smalltalk
Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Pseudo-random_numbers/Combined_recursive_generator_MRG32k3a | Pseudo-random numbers/Combined recursive generator MRG32k3a | MRG32k3a Combined recursive generator (pseudo-code)
/* Constants */
/* First generator */
a1 = [0, 1403580, -810728]
m1 = 2**32 - 209
/* Second Generator */
a2 = [527612, 0, -1370589]
m2 = 2**32 - 22853
d = m1 + 1
class MRG32k3a
x1 = [0, 0, 0] /* list of three last values of... | #C.2B.2B | C++ | #include <array>
#include <iostream>
int64_t mod(int64_t x, int64_t y) {
int64_t m = x % y;
if (m < 0) {
if (y < 0) {
return m - y;
} else {
return m + y;
}
}
return m;
}
class RNG {
private:
// First generator
const std::array<int64_t, 3> a1{ ... | Give a code snippet in #C.2B.2B
MRG32k3a Combined recursive generator (pseudo-code)
/* Constants */
/* First generator */
a1 = [0, 1403580, -810728]
m1 = 2**32 - 209
/* Second Generator */
a2 = [527612, 0, -1370589]
m2 = 2**32 - 22853
d = m1 + 1
class MRG32k3a
x1 = [0, 0, 0]... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rename_a_file | Rename a file | Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the rights to do so.
(In unix-type s... | #DBL | DBL | XCALL RENAM ("output.txt","input.txt")
.IFDEF UNIX
XCALL SPAWN ("mv docs mydocs")
.ENDC
.IFDEF DOS
XCALL SPAWN ("ren docs mydocs")
.ENDC
.IFDEF VMS
XCALL SPAWN ("rename docs.dir mydocs.dir")
.ENDC | Give a code snippet in #DBL
Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the righ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pythagoras_tree | Pythagoras tree |
The Pythagoras tree is a fractal tree constructed from squares. It is named after Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to represent the Pythagorean theorem.
Task
Construct a Pythagoras tree of order 7 using only vectors (no rotation or ... | #QB64 | QB64 | _Title "Pythagoras Tree"
Dim As Integer sw, sh
sw = 640
sh = 480
Screen _NewImage(sw, sh, 32)
Call pythTree(sw / 2 - sw / 12, sh - 30, sw / 2 + sw / 12, sh - 30, 0)
Sleep
System
Sub pythTree (ax As Integer, ay As Integer, bx As Integer, by As Integer, depth As Integer)
Dim As Single cx, cy, dx, dy, ex, ey... | Give a code snippet in #QB64
The Pythagoras tree is a fractal tree constructed from squares. It is named after Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to represent the Pythagorean theorem.
Task
Construct a Pythagoras tree of order 7 using... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Roots_of_a_function | Roots of a function | Task
Create a program that finds and outputs the roots of a given function, range and (if applicable) step width.
The program should identify whether the root is exact or approximate.
For this task, use: ƒ(x) = x3 - 3x2 + 2x
| #Elixir | Elixir | defmodule RC do
def find_roots(f, range, step \\ 0.001) do
first .. last = range
max = last + step / 2
Stream.iterate(first, &(&1 + step))
|> Stream.take_while(&(&1 < max))
|> Enum.reduce(sign(first), fn x,sn ->
value = f.(x)
cond do
abs(value) < step / 100 ->
... | Give a code snippet in #Elixir
Task
Create a program that finds and outputs the roots of a given function, range and (if applicable) step width.
The program should identify whether the root is exact or approximate.
For this task, use: ƒ(x) = x3 - 3x2 + 2x
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Longest_common_subsequence | Longest common subsequence | Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strings drawn from an alphabet Σ of ... | #D | D | import std.stdio, std.array;
T[] lcs(T)(in T[] a, in T[] b) pure nothrow @safe {
if (a.empty || b.empty) return null;
if (a[0] == b[0])
return a[0] ~ lcs(a[1 .. $], b[1 .. $]);
const longest = (T[] x, T[] y) => x.length > y.length ? x : y;
return longest(lcs(a, b[1 .. $]), lcs(a[1 .. $], b));
... | Give a code snippet in #D
Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strings d... | 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,... | #Scala | Scala |
import scala.io.Source
object WebTime extends Application {
val text = Source.fromURL("http://tycho.usno.navy.mil/cgi-bin/timer.pl")
val utc = text.getLines.find(_.contains("UTC"))
utc match {
case Some(s) => println(s.substring(4))
case _ => println("error")
}
}
| Give a code snippet in #Scala
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 pa... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Universal_Turing_machine | Universal Turing machine | One of the foundational mathematical constructs behind computer science
is the universal Turing Machine.
(Alan Turing introduced the idea of such a machine in 1936–1937.)
Indeed one way to definitively prove that a language
is turing-complete
is to implement a universal Turing machine in it.
Task
Simulate such ... | #VBA | VBA | Option Base 1
Public Enum sett
name_ = 1
initState
endState
blank
rules
End Enum
Public incrementer As Variant, threeStateBB As Variant, fiveStateBB As Variant
'-- Machine definitions
Private Sub init()
incrementer = Array("Simple incrementer", _
"q0", _
"qf", _
"B", _
... | Give a code snippet in #VBA
One of the foundational mathematical constructs behind computer science
is the universal Turing Machine.
(Alan Turing introduced the idea of such a machine in 1936–1937.)
Indeed one way to definitively prove that a language
is turing-complete
is to implement a universal Turing machine i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #SNOBOL4 | SNOBOL4 | define('chr(n)') :(chr_end)
chr &alphabet tab(n) len(1) . chr :s(return)f(freturn)
chr_end
define('asc(str)c') :(asc_end)
asc str len(1) . c
&alphabet break(c) @asc :s(return)f(freturn)
asc_end
* # Test and display
output = char(65) ;* Built-in
output = chr(65)
... | Give a code snippet in #SNOBOL4
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Co... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Nonoblock | Nonoblock | Nonoblock is a chip off the old Nonogram puzzle.
Given
The number of cells in a row.
The size of each, (space separated), connected block of cells to fit in the row, in left-to right order.
Task
show all possible positions.
show the number of positions of the blocks for the following cases within the row. ... | #C.2B.2B | C++ |
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <numeric>
#include <string>
#include <vector>
typedef std::pair<int, std::vector<int> > puzzle;
class nonoblock {
public:
void solve( std::vector<puzzle>& p ) {
for( std::vector<puzzle>::iterator i = p.begin(); i != p.end(); i++ ) {
... | Give a code snippet in #C.2B.2B
Nonoblock is a chip off the old Nonogram puzzle.
Given
The number of cells in a row.
The size of each, (space separated), connected block of cells to fit in the row, in left-to right order.
Task
show all possible positions.
show the number of positions of the blocks for the... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Swift | Swift | func cholesky(matrix: [Double], n: Int) -> [Double] {
var res = [Double](repeating: 0, count: matrix.count)
for i in 0..<n {
for j in 0..<i+1 {
var s = 0.0
for k in 0..<j {
s += res[i * n + k] * res[j * n + k]
}
if i == j {
res[i * n + j] = (matrix[i * n + i] - s).s... | Give a code snippet in #Swift
Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Program_termination | Program termination |
Task
Show the syntax for a complete stoppage of a program inside a conditional.
This includes all threads/processes which are part of your program.
Explain the cleanup (or lack thereof) caused by the termination (allocated memory, database connections, open files, object finalizers/destructors, run-on-exit hooks... | #Batch_File | Batch File | if condition exit | Give a code snippet in #Batch_File
Task
Show the syntax for a complete stoppage of a program inside a conditional.
This includes all threads/processes which are part of your program.
Explain the cleanup (or lack thereof) caused by the termination (allocated memory, database connections, open files, object final... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Roman_numerals/Encode | Roman numerals/Encode | Task
Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero.
In Roman numeral... | #Arturo | Arturo | nums: [[1000 "M"] [900 "CM"] [500 "D"] [400 "CD"] [100 "C"] [90 "XC"]
[50 "L"] [40 "XL"] [10 "X"] [9 "IX"] [5 "V"] [4 "IV"] [1 "I"])
toRoman: function [x][
ret: ""
idx: 0
initial: x
loop nums 'num [
d: num\0
l: num\1
i: 0
while [i<initial/d] [
ret: ret ++ l
... | Give a code snippet in #Arturo
Task
Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a va... | 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... | #AutoIt | AutoIt |
$irnd = Random(1, 10, 1)
$iinput = -1
While $input <> $irnd
$iinput = InputBox("Choose a number", "Please chosse a Number between 1 and 10")
WEnd
MsgBox(0, "Success", "Well guessed!")
| Give a code snippet in #AutoIt
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Algebraic_data_types | Algebraic data types | Some languages offer direct support for algebraic data types and pattern matching on them. While this of course can always be simulated with manual tagging and conditionals, it allows for terse code which is easy to read, and can represent the algorithm directly.
Task
As an example, implement insertion in a red-bla... | #Clojure | Clojure | (mapc #'use-package '(#:toadstool #:toadstool-system))
(defstruct (red-black-tree (:constructor tree (color left val right)))
color left val right)
(defcomponent tree (operator macro-mixin))
(defexpand tree (color left val right)
`(class red-black-tree red-black-tree-color ,color
red-blac... | Give a code snippet in #Clojure
Some languages offer direct support for algebraic data types and pattern matching on them. While this of course can always be simulated with manual tagging and conditionals, it allows for terse code which is easy to read, and can represent the algorithm directly.
Task
As an example,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Active_object | Active object | In object-oriented programming an object is active when its state depends on clock. Usually an active object encapsulates a task that updates the object's state. To the outer world the object looks like a normal object with methods that can be called from outside. Implementation of such methods must have a certain sync... | #F.23 | F# | open System
open System.Threading
// current time in seconds
let now() = float( DateTime.Now.Ticks / 10000L ) / 1000.0
type Integrator( intervalMs ) as x =
let mutable k = fun _ -> 0.0 // function to integrate
let mutable s = 0.0 // current value
let mutable t0 = now() // last time s was upd... | Give a code snippet in #F.23
In object-oriented programming an object is active when its state depends on clock. Usually an active object encapsulates a task that updates the object's state. To the outer world the object looks like a normal object with methods that can be called from outside. Implementation of such me... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Text_processing/2 | Text processing/2 | The following task concerns data that came from a pollution monitoring station with twenty-four instruments monitoring twenty-four aspects of pollution in the air. Periodically a record is added to the file, each record being a line of 49 fields separated by white-space, which can be one or more space or tab characters... | #Ursala | Ursala | #import std
#import nat
readings = (*F ~&c/;digits+ rlc ==+ ~~ -={` ,9%cOi&,13%cOi&}) readings_dot_txt
valid_format = all -&length==49,@tK27 all ~&w/`.&& ~&jZ\digits--'-.',@tK28 all ~&jZ\digits--'-'&-
duplicate_dates = :/'duplicated dates:'+ ~&hK2tFhhPS|| -[(none)]-!
good_readings = --' good readin... | Give a code snippet in #Ursala
The following task concerns data that came from a pollution monitoring station with twenty-four instruments monitoring twenty-four aspects of pollution in the air. Periodically a record is added to the file, each record being a line of 49 fields separated by white-space, which can be one... | christopher/rosetta-code | |
http://rosettacode.org/wiki/MAC_Vendor_Lookup | MAC Vendor Lookup | Every connected device around the world comes with a unique Media Access Control address, or a MAC address.
A common task a network administrator may come across is being able to identify a network device's manufacturer when given only a MAC address.
Task
Interface with one (or numerous) APIs that exist on the i... | #Python | Python | import requests
for addr in ['88:53:2E:67:07:BE', 'FC:FB:FB:01:FA:21',
'D4:F4:6F:C9:EF:8D', '23:45:67']:
vendor = requests.get('http://api.macvendors.com/' + addr).text
print(addr, vendor) | Give a code snippet in #Python
Every connected device around the world comes with a unique Media Access Control address, or a MAC address.
A common task a network administrator may come across is being able to identify a network device's manufacturer when given only a MAC address.
Task
Interface with one (or nu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Line_printer | Hello world/Line printer | Task
Cause a line printer attached to the computer to print a line containing the message: Hello World!
Note
A line printer is not the same as standard output.
A line printer was an older-style printer which prints one line at a time to a continuous ream of paper.
With some systems, a line printer can be... | #Ol | Ol |
(define p (open-output-file "/dev/lp0"))
(when p
(print-to p "Hello world!")
(close-port p))
| Give a code snippet in #Ol
Task
Cause a line printer attached to the computer to print a line containing the message: Hello World!
Note
A line printer is not the same as standard output.
A line printer was an older-style printer which prints one line at a time to a continuous ream of paper.
With some sy... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Check_output_device_is_a_terminal | Check output device is a terminal | Task
Demonstrate how to check whether the output device is a terminal or not.
Related task
Check input device is a terminal
| #Tcl | Tcl | set toTTY [dict exists [fconfigure stdout] -mode]
puts [expr {$toTTY ? "Output goes to tty" : "Output doesn't go to tty"}] | Give a code snippet in #Tcl
Task
Demonstrate how to check whether the output device is a terminal or not.
Related task
Check input device is a terminal
| christopher/rosetta-code | |
http://rosettacode.org/wiki/SHA-256 | SHA-256 | SHA-256 is the recommended stronger alternative to SHA-1. See FIPS PUB 180-4 for implementation details.
Either by using a dedicated library or implementing the algorithm in your language, show that the SHA-256 digest of the string "Rosetta code" is: 764faf5c61ac315f1497f9dfa542713965b785e5cc2f707d6468d7d1124cdfcf
| #Racket | Racket |
#lang racket/base
;; define a quick SH256 FFI interface, similar to the Racket's default
;; SHA1 interface
(require ffi/unsafe ffi/unsafe/define openssl/libcrypto
(only-in openssl/sha1 bytes->hex-string))
(define-ffi-definer defcrypto libcrypto)
(defcrypto SHA256_Init (_fun _pointer -> _int))
(defcrypto ... | Give a code snippet in #Racket
SHA-256 is the recommended stronger alternative to SHA-1. See FIPS PUB 180-4 for implementation details.
Either by using a dedicated library or implementing the algorithm in your language, show that the SHA-256 digest of the string "Rosetta code" is: 764faf5c61ac315f1497f9dfa542713965b7... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Circles_of_given_radius_through_two_points | Circles of given radius through two points |
Given two points on a plane and a radius, usually two circles of given radius can be drawn through the points.
Exceptions
r==0.0 should be treated as never describing circles (except in the case where the points are coincident).
If the points are coincident then an infinite number of circles with the point on thei... | #Python | Python | from collections import namedtuple
from math import sqrt
Pt = namedtuple('Pt', 'x, y')
Circle = Cir = namedtuple('Circle', 'x, y, r')
def circles_from_p1p2r(p1, p2, r):
'Following explanation at http://mathforum.org/library/drmath/view/53027.html'
if r == 0.0:
raise ValueError('radius of zero')
... | Give a code snippet in #Python
Given two points on a plane and a radius, usually two circles of given radius can be drawn through the points.
Exceptions
r==0.0 should be treated as never describing circles (except in the case where the points are coincident).
If the points are coincident then an infinite number o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/A%2BB | A+B | A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separated by space(s):
(
−
1000
≤... | #XLISP | XLISP | (DEFUN A-PLUS-B ()
(DISPLAY "Enter two numbers separated by a space.")
(NEWLINE)
(DISPLAY "> ")
(DEFINE A (READ))
(DEFINE B (READ))
(+ A B)) | Give a code snippet in #XLISP
A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separate... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives ... | #R | R |
library(combinat)
col <- factor(c("Red","Green","White","Yellow","Blue"))
own <- factor(c("English","Swedish","Danish","German","Norwegian"))
pet <- factor(c("Dog","Birds","Cats","Horse","Zebra"))
drink <- factor(c("Coffee","Tea","Milk","Beer","Water"))
smoke <- factor(c("PallMall", "Blend", "Dunhill", "BlueMaste... | Give a code snippet in #R
Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #Perl | Perl | sub entropy {
my %count; $count{$_}++ for @_;
my $entropy = 0;
for (values %count) {
my $p = $_/@_;
$entropy -= $p * log $p;
}
$entropy / log 2
}
print entropy split //, "1223334444"; | Give a code snippet in #Perl
Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), t... | 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... | #Bracmat | Bracmat | No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall. | Give a code snippet in #Bracmat
Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Order_two_numerical_lists | Order two numerical lists | sorting
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
She... | #ACL2 | ACL2 | ACL2 !>(lexorder '(1 2 3) '(1 2 3 4))
T
ACL2 !>(lexorder '(1 2 4) '(1 2 3))
NIL | Give a code snippet in #ACL2
sorting
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/Sleeping_Beauty_problem | Sleeping Beauty problem | Background on the task
In decision theory, The Sleeping Beauty Problem
is a problem invented by Arnold Zoboff and first publicized on Usenet. The experimental
subject, named Sleeping Beauty, agrees to an experiment as follows:
Sleeping Beauty volunteers to be put into a deep sleep on a Sunday. There is then a fair coin... | #Python | Python | from random import choice
def sleeping_beauty_experiment(repetitions):
"""
Run the Sleeping Beauty Problem experiment `repetitions` times, checking to see
how often we had heads on waking Sleeping Beauty.
"""
gotheadsonwaking = 0
wakenings = 0
for _ in range(repetitions):
coin_resu... | Give a code snippet in #Python
Background on the task
In decision theory, The Sleeping Beauty Problem
is a problem invented by Arnold Zoboff and first publicized on Usenet. The experimental
subject, named Sleeping Beauty, agrees to an experiment as follows:
Sleeping Beauty volunteers to be put into a deep sleep on a S... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cut_a_rectangle | Cut a rectangle | A given rectangle is made from m × n squares. If m and n are not both odd, then it is possible to cut a path through the rectangle along the square edges such that the rectangle splits into two connected pieces with the same shape (after rotating one of the pieces by 180°). All such paths for 2 × 2 and 4 × 3 rectangles... | #Raku | Raku | sub solve($hh, $ww, $recurse) {
my ($h, $w, $t, @grid) = $hh, $ww, 0;
state $cnt;
$cnt = 0 if $recurse;
($t, $w, $h) = ($w, $h, $w) if $h +& 1;
return 0 if $h == 1;
return 1 if $w == 1;
return $h if $w == 2;
return $w if $h == 2;
my ($cy, $cx) = ($h, $w) «div» 2;
my $len = ... | Give a code snippet in #Raku
A given rectangle is made from m × n squares. If m and n are not both odd, then it is possible to cut a path through the rectangle along the square edges such that the rectangle splits into two connected pieces with the same shape (after rotating one of the pieces by 180°). All such paths ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rock-paper-scissors | Rock-paper-scissors | Task
Implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI (artificial intelligence) player.
Rock Paper Scissors is a two player game.
Each player chooses one of rock, paper or scissors, without knowing the other player's choice.
The winner is decided by a set of rules:
... | #TorqueScript | TorqueScript |
while(isobject(RockPaperScissors))
RockPaperScissors.delete();
new scriptObject(RockPaperScissors);
function RockPaperScissors::startGame(%this)
{
%this.idle = true;
echo("Starting rock paper scissors, please type choose(\"choice\"); to proceed!");
}
function RockPaperScissors::endGame(%this)
{
%this.idle =... | Give a code snippet in #TorqueScript
Task
Implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI (artificial intelligence) player.
Rock Paper Scissors is a two player game.
Each player chooses one of rock, paper or scissors, without knowing the other player's choice.
The... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.... | #Fortran | Fortran |
!***************************************************************************************************
module evolve_routines
!***************************************************************************************************
implicit none
!the target string:
character(len=*),parameter :: targ = 'METHINKS ... | Give a code snippet in #Fortran
Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Increment_loop_index_within_loop_body | Loops/Increment loop index within loop body | Sometimes, one may need (or want) a loop which
its iterator (the index
variable) is modified within the
loop body in addition to the normal incrementation by the (do) loop structure index.
Goal
Demonstrate the best way to accomplish this.
Task
Write a loop which:
starts the index (variable... | #Seed7 | Seed7 | $ include "seed7_05.s7i";
const func boolean: isPrime (in integer: number) is func
result
var boolean: result is FALSE;
local
var integer: count is 2;
begin
if number = 2 then
result := TRUE;
elsif number > 2 then
while number rem count <> 0 and count * count <= number do
inc... | Give a code snippet in #Seed7
Sometimes, one may need (or want) a loop which
its iterator (the index
variable) is modified within the
loop body in addition to the normal incrementation by the (do) loop structure index.
Goal
Demonstrate the best way to accomplish this.
Task
Write a loop which:... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Twelve_statements | Twelve statements | This puzzle is borrowed from math-frolic.blogspot.
Given the following twelve statements, which of them are true?
1. This is a numbered list of twelve statements.
2. Exactly 3 of the last 6 statements are true.
3. Exactly 2 of the even-numbered statements are true.
4. If statement 5 is true, then statemen... | #Tcl | Tcl | package require Tcl 8.6
# Function to evaluate the truth of a statement
proc tcl::mathfunc::S {idx} {
upvar 1 state s
apply [lindex $s [expr {$idx - 1}]] $s
}
# Procedure to count the number of statements which are true
proc S+ args {
upvar 1 state state
tcl::mathop::+ {*}[lmap i $args {expr {S($i)}}]... | Give a code snippet in #Tcl
This puzzle is borrowed from math-frolic.blogspot.
Given the following twelve statements, which of them are true?
1. This is a numbered list of twelve statements.
2. Exactly 3 of the last 6 statements are true.
3. Exactly 2 of the even-numbered statements are true.
4. If state... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Image_noise | Image noise | Generate a random black and white 320x240 image continuously,
showing FPS (frames per second).
A sample image
| #Axe | Axe | .Enable 15 MHz full speed mode
Full
.Disable memory access delays (adds 1 FPS)
Fullʳ
.Flush key presses
While getKey(0)
End
.Setup
0→F
0→N
Fix 5
fnInt(FPS,6)
Repeat getKey(0)
NOISE()
F++
.Reset the FPS counter before it overflows
F>606?0→F→N
Text(0,0,F*108/N▶Dec)
DispGraph
End
.Clean up
LnRegʳ
Fix 4
Retur... | Give a code snippet in #Axe
Generate a random black and white 320x240 image continuously,
showing FPS (frames per second).
A sample image
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Langton%27s_ant | Langton's ant | Langton's ant is a cellular automaton that models an ant sitting on a plane of cells, all of which are white initially, the ant facing in one of four directions.
Each cell can either be black or white.
The ant moves according to the color of the cell it is currently sitting in, with the following rules:
If the ce... | #Icon_and_Unicon | Icon and Unicon | link graphics,printf
procedure main(A)
e := ( 0 < integer(\A[1])) | 100 # 100 or whole number from command line
LangtonsAnt(e)
end
record antrec(x,y,nesw)
procedure LangtonsAnt(e)
size := sprintf("size=%d,%d",e,e)
label := sprintf("Langton's Ant %dx%d [%d]",e,e,0)
&window := open(label,"g","bg=... | Give a code snippet in #Icon_and_Unicon
Langton's ant is a cellular automaton that models an ant sitting on a plane of cells, all of which are white initially, the ant facing in one of four directions.
Each cell can either be black or white.
The ant moves according to the color of the cell it is currently sitting in... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Simple_moving_average | Averages/Simple moving average | Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is a method for computing an avera... | #Elena | Elena | import system'routines;
import system'collections;
import extensions;
class SMA
{
object thePeriod;
object theList;
constructor new(period)
{
thePeriod := period;
theList :=new List();
}
append(n)
{
theList.append(n);
var count := theList.Length;
... | Give a code snippet in #Elena
Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #jq | jq | # Input: an array of strings.
# Output: an object with the strings as keys, the values of which are the corresponding frequencies.
def counter:
reduce .[] as $item ( {}; .[$item] += 1 ) ;
# entropy in bits of the input string
def entropy:
(explode | map( [.] | implode ) | counter
| [ .[] | . * log ] | add) as... | Give a code snippet in #jq
Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the... | 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... | #Julia | Julia |
# Calling a function that requires no arguments:
f() = print("Hello world!")
f()
# Calling a function with a fixed number of arguments:
function f(x, y, z)
x*y - z^2
end
f(3, 4, 2)
# Calling a function with optional arguments:
# Note Julia uses multiple dispatch based on argument number and type, so... | Give a code snippet in #Julia
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 va... | christopher/rosetta-code |
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