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/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S... | #D | D | import std.stdio, std.range;
const struct CombRep {
immutable uint nt, nc;
private const ulong[] combVal;
this(in uint numType, in uint numChoice) pure nothrow @safe
in {
assert(0 < numType && numType + numChoice <= 64,
"Valid only for nt + nc <= 64 (ulong bit size)");
} b... | Give a code snippet in #D
The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of thos... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using ... | #JavaScript | JavaScript | (() => {
'use strict';
// vanEck :: Int -> [Int]
const vanEck = n =>
reverse(
churchNumeral(n)(
xs => 0 < xs.length ? cons(
maybe(
0, succ,
elemIndex(xs[0], xs.slice(1))
),
... | Give a code snippet in #JavaScript
The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term oc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Break_OO_privacy | Break OO privacy | Show how to access private or protected members of a class in an object-oriented language from outside an instance of the class, without calling non-private or non-protected members of the class as a proxy.
The intent is to show how a debugger, serializer, or other meta-programming tool might access information that is... | #F.23 | F# | open System
open System.Reflection
type MyClass() =
let answer = 42
member this.GetAnswer
with get() = answer
[<EntryPoint>]
let main argv =
let myInstance = MyClass()
let fieldInfo = myInstance.GetType().GetField("answer", BindingFlags.NonPublic ||| BindingFlags.Instance)
let answer ... | Give a code snippet in #F.23
Show how to access private or protected members of a class in an object-oriented language from outside an instance of the class, without calling non-private or non-protected members of the class as a proxy.
The intent is to show how a debugger, serializer, or other meta-programming tool mi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Binary_strings | Binary strings | Many languages have powerful and useful (binary safe) string manipulation functions, while others don't, making it harder for these languages to accomplish some tasks.
This task is about creating functions to handle binary strings (strings made of arbitrary bytes, i.e. byte strings according to Wikipedia) for those la... | #Kotlin | Kotlin | class ByteString(private val bytes: ByteArray) : Comparable<ByteString> {
val length get() = bytes.size
fun isEmpty() = bytes.isEmpty()
operator fun plus(other: ByteString): ByteString = ByteString(bytes + other.bytes)
operator fun plus(byte: Byte) = ByteString(bytes + byte)
operator fun get... | Give a code snippet in #Kotlin
Many languages have powerful and useful (binary safe) string manipulation functions, while others don't, making it harder for these languages to accomplish some tasks.
This task is about creating functions to handle binary strings (strings made of arbitrary bytes, i.e. byte strings acco... | christopher/rosetta-code | |
http://rosettacode.org/wiki/4-rings_or_4-squares_puzzle | 4-rings or 4-squares puzzle | 4-rings or 4-squares puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Replace a, b, c, d, e, f, and
g with the decimal
digits LOW ───► HIGH
such that the sum of the letters inside of each of the four large squares add up to
t... | #Factor | Factor | USING: arrays backtrack formatting grouping kernel locals math
math.ranges prettyprint sequences sequences.generalizations
sets ;
IN: rosetta-code.4-rings
:: 4-rings ( lo hi unique? -- seq ) [
7 [ lo hi [a,b] amb-lazy ] replicate
7 firstn :> ( a b c d e f g )
{ a b c d e f g } :> p
a b... | Give a code snippet in #Factor
4-rings or 4-squares puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Replace a, b, c, d, e, f, and
g with the decimal
digits LOW ───► HIGH
such that the sum of the letters inside of each of th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Integer_sequence | Integer sequence | Task
Create a program that, when run, would display all integers from 1 to ∞ (or any relevant implementation limit), in sequence (i.e. 1, 2, 3, 4, etc) if given enough time.
An example may not be able to reach arbitrarily-large numbers based on implementations limits. For example, if integer... | #E | E | for i in int > 0 { println(i) } | Give a code snippet in #E
Task
Create a program that, when run, would display all integers from 1 to ∞ (or any relevant implementation limit), in sequence (i.e. 1, 2, 3, 4, etc) if given enough time.
An example may not be able to reach arbitrarily-large numbers based on implementations limits... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cuban_primes | Cuban primes | The name cuban has nothing to do with Cuba (the country), but has to do with the
fact that cubes (3rd powers) play a role in its definition.
Some definitions of cuban primes
primes which are the difference of two consecutive cubes.
primes of the form: (n+1)3 - n3.
primes of the form: n3 - ... | #Kotlin | Kotlin | import kotlin.math.ceil
import kotlin.math.sqrt
fun main() {
val primes = mutableListOf(3L, 5L)
val cutOff = 200
val bigUn = 100_000
val chunks = 50
val little = bigUn / chunks
println("The first $cutOff cuban primes:")
var showEach = true
var c = 0
var u = 0L
var v = 1L
... | Give a code snippet in #Kotlin
The name cuban has nothing to do with Cuba (the country), but has to do with the
fact that cubes (3rd powers) play a role in its definition.
Some definitions of cuban primes
primes which are the difference of two consecutive cubes.
primes of the form: (n+1)3 - n3... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Box_the_compass | Box the compass | There be many a land lubber that knows naught of the pirate ways and gives direction by degree!
They know not how to box the compass!
Task description
Create a function that takes a heading in degrees and returns the correct 32-point compass heading.
Use the function to print and display a table of Index, Compass... | #QBasic | QBasic | DECLARE FUNCTION compasspoint$ (h!)
DIM SHARED POINT$(32)
FOR i = 1 TO 32
READ d$: POINT$(i) = d$
NEXT i
FOR i = 0 TO 32
heading = i * 11.25
IF (i MOD 3) = 1 THEN
heading = heading + 5.62
ELSE
IF (i MOD 3) = 2 THEN heading = heading - 5.62
END IF
ind = i MOD 32 + 1
PRIN... | Give a code snippet in #QBasic
There be many a land lubber that knows naught of the pirate ways and gives direction by degree!
They know not how to box the compass!
Task description
Create a function that takes a heading in degrees and returns the correct 32-point compass heading.
Use the function to print and d... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Leap_year | Leap year | Task
Determine whether a given year is a leap year in the Gregorian calendar.
See also
Leap year (wiki)
| #Befunge | Befunge | 0"2("*:3-:1-:2-:"^"-v<
v*%"d"\!%4::,,"is".:<|
>\45*:*%!+#v_ "ton"vv<
v"ear."+550<,,,,*84<$#
>"y pael a ">:#,_$:#@^ | Give a code snippet in #Befunge
Task
Determine whether a given year is a leap year in the Gregorian calendar.
See also
Leap year (wiki)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Singly-linked_list/Traversal | Singly-linked list/Traversal | Traverse from the beginning of a singly-linked list to the end.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked ... | #Phix | Phix | with javascript_semantics
enum NEXT,DATA
constant empty_sll = {{1}}
sequence sll = deep_copy(empty_sll)
procedure insert_after(object data, integer pos=length(sll))
sll = append(sll,{sll[pos][NEXT],data})
sll[pos][NEXT] = length(sll)
end procedure
insert_after("ONE")
insert_after("TWO")
insert_after("THREE"... | Give a code snippet in #Phix
Traverse from the beginning of a singly-linked list to the end.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definiti... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Safe_primes_and_unsafe_primes | Safe primes and unsafe primes | Definitions
A safe prime is a prime p and where (p-1)/2 is also prime.
The corresponding prime (p-1)/2 is known as a Sophie Germain prime.
An unsafe prime is a prime p and where (p-1)/2 isn't a prime.
An unsafe prime is a prime that isn't a safe prime.
Task
... | #Ksh | Ksh |
#!/bin/ksh
# Safe primes and unsafe primes
# # Variables:
#
integer safecnt=0 safedisp=35 safecnt1M=0
integer unsacnt=0 unsadisp=40 unsacnt1M=0
typeset -a safeprime unsafeprime
# # Functions:
#
# # Function _isprime(n) return 1 for prime, 0 for not prime
#
function _isprime {
typeset _n ; integer _n=$1
type... | Give a code snippet in #Ksh
Definitions
A safe prime is a prime p and where (p-1)/2 is also prime.
The corresponding prime (p-1)/2 is known as a Sophie Germain prime.
An unsafe prime is a prime p and where (p-1)/2 isn't a prime.
An unsafe prime is a prime that isn't ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Quine | Quine | A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program ... | #HTML | HTML | <!DOCTYPE html>
<html>
<head>
<title>HTML/CSS Quine</title>
<style type="text/css">
* { font: 10pt monospace; }
head, style { display: block; }
style { white-space: pre; }
style:before {
content:
"\3C""!DOCTYPE html\3E"
"\A\3Chtml\3E\A"
"\3Chead\3E\A"
"\9\3Ctitle\3E""HTML/CSS Quine""\3C/title\3E... | Give a code snippet in #HTML
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
... | 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
... | #FutureBasic | FutureBasic | window 1, @"Primality By Trial Division", (0,0,480,270)
local fn isPrime( n as long ) as Boolean
long i
Boolean result
if n < 2 then result = NO : exit fn
if n = 2 then result = YES : exit fn
if n mod 2 == 0 then result = NO : exit fn
result = YES
for i = 3 to int( n^.5 ) step 2
if n mod i =... | Give a code snippet in #FutureBasic
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Associative_array/Creation | Associative array/Creation | Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element ins... | #Wren | Wren | var fruit = {} // creates an empty map
fruit[1] = "orange" // associates a key of 1 with "orange"
fruit[2] = "apple" // associates a key of 2 with "apple"
System.print(fruit[1]) // retrieves the value with a key of 1 and prints it out
fruit.remove(1) ... | Give a code snippet in #Wren
Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, E... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | (Local) In[1]:= Binomial[5,3]
(Local) Out[1]= 10 | Give a code snippet in #Mathematica_.2F_Wolfram_Language
This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Gray_code | Gray code | Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The follow... | #NOWUT | NOWUT | ; link with PIOxxx.OBJ
sectiondata
output: db " : "
inbinary: db "00000 => "
graybinary: db "00000 => "
outbinary: db "00000"
db 13,10,0 ; carriage return and null terminator
sectioncode
start!
gosub initplatform
beginfunc
l... | Give a code snippet in #NOWUT
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Polymorphic_copy | Polymorphic copy | An object is polymorphic when its specific type may vary.
The types a specific value may take, is called class.
It is trivial to copy an object if its type is known:
int x;
int y = x;
Here x is not polymorphic, so y is declared of same type (int) as x.
But if the specific type of x were unknown, then y could not be d... | #JavaScript | JavaScript | function clone(obj){
if (obj == null || typeof(obj) != 'object')
return obj;
var temp = {};
for (var key in obj)
temp[key] = clone(obj[key]);
return temp;
} | Give a code snippet in #JavaScript
An object is polymorphic when its specific type may vary.
The types a specific value may take, is called class.
It is trivial to copy an object if its type is known:
int x;
int y = x;
Here x is not polymorphic, so y is declared of same type (int) as x.
But if the specific type of x... | christopher/rosetta-code | |
http://rosettacode.org/wiki/MD4 | MD4 | Find the MD4 message digest of a string of octets.
Use the ASCII encoded string “Rosetta Code” (without quotes).
You may either call an MD4 library, or implement MD4 in your language.
MD4 is an obsolete hash function that computes a 128-bit message digest that sometimes appears in obsolete protocols.
RFC 1320 specifi... | #Python | Python | import hashlib
print hashlib.new("md4",raw_input().encode('utf-16le')).hexdigest().upper() | Give a code snippet in #Python
Find the MD4 message digest of a string of octets.
Use the ASCII encoded string “Rosetta Code” (without quotes).
You may either call an MD4 library, or implement MD4 in your language.
MD4 is an obsolete hash function that computes a 128-bit message digest that sometimes appears in obsol... | 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... | #Euphoria | Euphoria | printf(1,"%d\n", 'a') -- prints "97"
printf(1,"%s\n", 97) -- prints "a" | Give a code snippet in #Euphoria
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).
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #HicEst | HicEst | END ! looks better, but is not really needed | Give a code snippet in #HicEst
Task
Create the simplest possible program that is still considered "correct."
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits ... | #Lingo | Lingo | -- parent script "BitArray"
property ancestor
property bitSize
property _pow2
----------------------------------------
-- @constructor
-- @param {integer} [bSize=0]
----------------------------------------
on new (me, bSize)
if voidP(bitSize) then bitSize=0
me.bitSize = bSize
byteSize = bitSize/8 + (bitSize m... | Give a code snippet in #Lingo
The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Classes | Classes | In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the class.
A class of types itself, a... | #SuperCollider | SuperCollider |
SpecialObject {
classvar a = 42, <b = 0, <>c; // Class variables. 42 and 0 are default values.
var <>x, <>y; // Instance variables.
// Note: variables are private by default. In the above, "<" creates a getter, ">" creates a setter
*new { |value|
^super.new.init(value) // constructo... | Give a code snippet in #SuperCollider
In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Do-while | Loops/Do-while | Start with a value at 0. Loop while value mod 6 is not equal to 0.
Each time through the loop, add 1 to the value then print it.
The loop must execute at least once.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loo... | #SPL | SPL | n = 0
>
n += 1
#.output(n)
< n%6 | Give a code snippet in #SPL
Start with a value at 0. Loop while value mod 6 is not equal to 0.
Each time through the loop, add 1 to the value then print it.
The loop must execute at least once.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Dow... | 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... | #11l | 11l | F sleeping_beauty_experiment(repetitions)
‘
Run the Sleeping Beauty Problem experiment `repetitions` times, checking to see
how often we had heads on waking Sleeping Beauty.
’
V gotheadsonwaking = 0
V wakenings = 0
L 0 .< repetitions
V coin_result = random:choice([‘heads’, ‘tails’])
... | Give a code snippet in #11l
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 Sund... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Execute_HQ9%2B | Execute HQ9+ | Task
Implement a HQ9+ interpreter or compiler.
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | hq9plus[program_] :=
Module[{accumulator = 0, bottle},
bottle[n_] :=
ToString[n] <> If[n == 1, " bottle", " bottles"] <> " of beer";
Do[Switch[chr, "H", Print@"hello, world", "Q", Print@program, "9",
Print@StringJoin[
Table[bottle[n] <> " on the wall\n" <> bottle[n] <>
"\ntake one down, ... | Give a code snippet in #Mathematica_.2F_Wolfram_Language
Task
Implement a HQ9+ interpreter or compiler.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Reflection/List_properties | Reflection/List properties | Task
The goal is to get the properties of an object, as names, values or both.
Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
| #PicoLisp | PicoLisp |
# The Rectangle class
(class +Rectangle +Shape)
# dx dy
(dm T (X Y DX DY)
(super X Y)
(=: dx DX)
(=: dy DY) )
(dm area> ()
(* (: dx) (: dy)) )
(dm perimeter> ()
(* 2 (+ (: dx) (: dy))) )
(dm draw> ()
(drawRect (: x) (: y) (: dx) (: dy)) ) # Hypothetical function 'drawRect'
| Give a code snippet in #PicoLisp
Task
The goal is to get the properties of an object, as names, values or both.
Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/GUI_component_interaction | GUI component interaction |
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dial... | #PicoLisp | PicoLisp | #!/usr/bin/picolisp /usr/lib/picolisp/lib.l
(load "@ext.l" "@lib/http.l" "@lib/xhtml.l" "@lib/form.l")
(de start ()
(and (app) (zero *Number))
(action
(html 0 "Increment" "@lib.css" NIL
(form NIL
(gui '(+Var +NumField) '*Number 20 "Value")
(gui '(+JS +Button) "increment"... | Give a code snippet in #PicoLisp
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and chec... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Append_a_record_to_the_end_of_a_text_file | Append a record to the end of a text file | Many systems offer the ability to open a file for writing, such that any data written will be appended to the end of the file. Further, the file operations will always adjust the position pointer to guarantee the end of the file, even in a multitasking environment.
This feature is most useful in the case of log files,... | #C.2B.2B | C++ | #include <iostream>
#include <fstream>
#include <string>
#include <vector>
std::ostream& operator<<(std::ostream& out, const std::string s) {
return out << s.c_str();
}
struct gecos_t {
std::string fullname, office, extension, homephone, email;
friend std::ostream& operator<<(std::ostream&, const geco... | Give a code snippet in #C.2B.2B
Many systems offer the ability to open a file for writing, such that any data written will be appended to the end of the file. Further, the file operations will always adjust the position pointer to guarantee the end of the file, even in a multitasking environment.
This feature is most... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Totient_function | Totient function | The totient function is also known as:
Euler's totient function
Euler's phi totient function
phi totient function
Φ function (uppercase Greek phi)
φ function (lowercase Greek phi)
Definitions (as per number theory)
The totient function:
counts the integers up to a given positiv... | #J | J |
nth_prime =: p: NB. 2 is the zeroth prime
totient =: 5&p:
primeQ =: 1&p:
NB. first row contains the integer
NB. second row totient
NB. third 1 iff prime
(, totient ,: primeQ) >: i. 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1 1 2 2 4 2 6 ... | Give a code snippet in #J
The totient function is also known as:
Euler's totient function
Euler's phi totient function
phi totient function
Φ function (uppercase Greek phi)
φ function (lowercase Greek phi)
Definitions (as per number theory)
The totient function:
counts the int... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Tokenize_a_string | Tokenize a string | Separate the string "Hello,How,Are,You,Today" by commas into an array (or list) so that each element of it stores a different word.
Display the words to the 'user', in the simplest manner possible, separated by a period.
To simplify, you may display a trailing period.
Other tasks related to string operations:
Me... | #Zoea | Zoea |
program: tokenize_a_string
input: "Hello,How,Are,You,Today"
output: "Hello.How.Are.You.Today"
| Give a code snippet in #Zoea
Separate the string "Hello,How,Are,You,Today" by commas into an array (or list) so that each element of it stores a different word.
Display the words to the 'user', in the simplest manner possible, separated by a period.
To simplify, you may display a trailing period.
Other tasks rel... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Angle_difference_between_two_bearings | Angle difference between two bearings | Finding the angle between two bearings is often confusing.[1]
Task
Find the angle which is the result of the subtraction b2 - b1, where b1 and b2 are the bearings.
Input bearings are expressed in the range -180 to +180 degrees.
The result is also expressed in the range -180 to +180 degrees.
... | #Racket | Racket | #lang racket
(define (% a b) (- a (* b (truncate (/ a b)))))
(define (bearing- bearing heading)
(- (% (+ (% (- bearing heading) 360) 540) 360) 180))
(module+ main
(bearing- 20 45)
(bearing- -45 45)
(bearing- -85 90)
(bearing- -95 90)
(bearing- -45 125)
(bearing- -45 145)
(bearing- 29.4803 -88.6381)
... | Give a code snippet in #Racket
Finding the angle between two bearings is often confusing.[1]
Task
Find the angle which is the result of the subtraction b2 - b1, where b1 and b2 are the bearings.
Input bearings are expressed in the range -180 to +180 degrees.
The result is also expressed in the range ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Align_columns | Align columns | Given a text file of many lines, where fields within a line
are delineated by a single 'dollar' character, write a program
that aligns each column of fields by ensuring that words in each
column are separated by at least one space.
Further, allow for each word in a column to be either left
justified, right justified, o... | #Amazing_Hopper | Amazing Hopper |
#define IGet(__N__,__X__) [__N__]SGet(__X__)
#include <hbasic.h>
#define MAX_LINE 1000
Begin
Option Stack 15
Declare as Numeric ( fd, i, index, max token )
as Numeric ( num tokens, size Column, tCells )
as Alpha ( line )
as Numeric ( display Left, display Right, display ... | Give a code snippet in #Amazing_Hopper
Given a text file of many lines, where fields within a line
are delineated by a single 'dollar' character, write a program
that aligns each column of fields by ensuring that words in each
column are separated by at least one space.
Further, allow for each word in a column to be e... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Doubly-linked_list/Element_insertion | Doubly-linked list/Element insertion | Doubly-Linked List (element)
This is much like inserting into a Singly-Linked List, but with added assignments so that the backwards-pointing links remain correct.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element inse... | #Yabasic | Yabasic | // Rosetta Code problem: http://rosettacode.org/wiki/Doubly-linked_list/Element_insertion & removal & traverse
// by Galileo, 02/2022
FIL = 1 : DATO = 2 : LPREV = 3 : LNEXT = 4
countNodes = 0 : Nodes = 10
dim list(Nodes, 4)
list(0, LNEXT) = 1
sub searchNode(node)
local i, Node
for i = 0 to node-1
... | Give a code snippet in #Yabasic
Doubly-Linked List (element)
This is much like inserting into a Singly-Linked List, but with added assignments so that the backwards-pointing links remain correct.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Wren | Wren | print frnfn_size("uint8") //1
print frnfn_size("int8") //1
print frnfn_size("uint16") //2
print frnfn_size("int16") //2
print frnfn_size("uint32") //4
print frnfn_size("int32") //4
print frnfn_size("uint64") //8
print frnfn_size("int64") //8
print frnfn_size("float") //4
print frnfn_size("double") //8
print f... | Give a code snippet in #Wren
Demonstrate how to get the size of a variable.
See also: Host introspection
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Old_lady_swallowed_a_fly | Old lady swallowed a fly | Task
Present a program which emits the lyrics to the song I Knew an Old Lady Who Swallowed a Fly, taking advantage of the repetitive structure of the song's lyrics.
This song has multiple versions with slightly different lyrics, so all these programs might not emit identical output.
Other tasks related to st... | #C.2B.2B | C++ | #include <iostream>
const char *CREATURES[] = { "fly", "spider", "bird", "cat", "dog", "goat", "cow", "horse" };
const char *COMMENTS[] = {
"I don't know why she swallowed that fly.\nPerhaps she'll die\n",
"That wiggled and jiggled and tickled inside her",
"How absurd, to swallow a bird",
"Imagine tha... | Give a code snippet in #C.2B.2B
Task
Present a program which emits the lyrics to the song I Knew an Old Lady Who Swallowed a Fly, taking advantage of the repetitive structure of the song's lyrics.
This song has multiple versions with slightly different lyrics, so all these programs might not emit identical outp... | 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... | #Picat | Picat | main =>
Digits = to_array("123456789"),
Size = 4,
random_sample(Size,Size,[],ChosenIndecies),
Chosen = {Digits[I] : I in ChosenIndecies},
printf("I have chosen a number from %d unique digits from 1 to 9 arranged in a random order.\n", Size),
printf("You need to input a %d digit, unique digit num... | Give a code snippet in #Picat
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multiplication_tables | Multiplication tables | Task
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
| #Scheme | Scheme |
(define iota
(lambda (count start step)
(let loop ((result (list (+ start (* (- count 1) step)))))
(let ((acc (car result)))
(if (= acc start)
result
(loop (cons (- acc step) result)))))))
(define table
(lambda (x)
(let loop ((count 1)
(numbers (iot... | Give a code snippet in #Scheme
Task
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_three_variables | Sort three variables |
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
... | #Free_Pascal | Free Pascal | {$mode objFPC}
generic procedure sort<T>(var X, Y: T);
procedure swap;
var
Z: T;
begin
Z := X;
X := Y;
Y := Z
end;
begin
if X > Y then
begin
swap
end
end;
generic procedure sort<T>(var X, Y, Z: T);
begin
specialize sort<T>(X, Y);
specialize sort<T>(X, Z);
specialize sort<T>(Y, Z)
end;
generic ... | Give a code snippet in #Free_Pascal
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Qu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/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
| #Ruby | Ruby | Array.new(1000) { 1 + Math.sqrt(-2 * Math.log(rand)) * Math.cos(2 * Math::PI * rand) } | Give a code snippet in #Ruby
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Symmetric_difference | Symmetric difference | Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{\displaystyle (A\cup B)\setminus (A... | #Action.21 | Action! | SET EndProg=* | Give a code snippet in #Action.21
Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Magic_squares_of_doubly_even_order | Magic squares of doubly even order | A magic square is an N×N square matrix whose numbers consist of consecutive numbers arranged so that the sum of each row and column, and both diagonals are equal to the same sum (which is called the magic number or magic constant).
A magic square of doubly even order has a size that is a multiple of four (e... | #C.23 | C# | using System;
namespace MagicSquareDoublyEven
{
class Program
{
static void Main(string[] args)
{
int n = 8;
var result = MagicSquareDoublyEven(n);
for (int i = 0; i < result.GetLength(0); i++)
{
for (int j = 0; j < result.GetLeng... | Give a code snippet in #C.23
A magic square is an N×N square matrix whose numbers consist of consecutive numbers arranged so that the sum of each row and column, and both diagonals are equal to the same sum (which is called the magic number or magic constant).
A magic square of doubly even order has a size t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Chernick%27s_Carmichael_numbers | Chernick's Carmichael numbers | In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(4, m) = U(3, m) * (2^2 * 9m + 1)... | #Nim | Nim | import strutils, sequtils
import bignum
const
Max = 10
Factors: array[3..Max, int] = [1, 1, 2, 4, 8, 16, 32, 64] # 1 for n=3 then 2^(n-4).
FirstPrimes = [3, 5, 7, 11, 13, 17, 19, 23]
#---------------------------------------------------------------------------------------------------
iterator factors(n, m:... | Give a code snippet in #Nim
In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(4, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Priority_queue | Priority queue | A priority queue is somewhat similar to a queue, with an important distinction: each item is added to a priority queue with a priority level, and will be later removed from the queue with the highest priority element first. That is, the items are (conceptually) stored in the queue in priority order instead of in insert... | #Erlang | Erlang |
-module( priority_queue ).
-export( [create/0, insert/3, peek/1, task/0, top/1] ).
create() -> gb_trees:empty().
insert( Element, Priority, Queue ) -> gb_trees:enter( Priority, Element, Queue ).
peek( Queue ) ->
{_Priority, Element, _New_queue} = gb_trees:take_smallest( Queue ),
Element.
task() ->
Ite... | Give a code snippet in #Erlang
A priority queue is somewhat similar to a queue, with an important distinction: each item is added to a priority queue with a priority level, and will be later removed from the queue with the highest priority element first. That is, the items are (conceptually) stored in the queue in pri... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Digital_root | Digital root | The digital root,
X
{\displaystyle X}
, of a number,
n
{\displaystyle n}
, is calculated:
find
X
{\displaystyle X}
as the sum of the digits of
n
{\displaystyle n}
find a new
X
{\displaystyle X}
by summing the digits of
X
{\displaystyle X}
, repeating until
X
{\displ... | #VBScript | VBScript | Function digital_root(n)
ap = 0
Do Until Len(n) = 1
x = 0
For i = 1 To Len(n)
x = x + CInt(Mid(n,i,1))
Next
n = x
ap = ap + 1
Loop
digital_root = "Additive Persistence = " & ap & vbCrLf &_
"Digital Root = " & n & vbCrLf
End Function
WScript.StdOut.Write digital_root(WScript.Arguments(0)) | Give a code snippet in #VBScript
The digital root,
X
{\displaystyle X}
, of a number,
n
{\displaystyle n}
, is calculated:
find
X
{\displaystyle X}
as the sum of the digits of
n
{\displaystyle n}
find a new
X
{\displaystyle X}
by summing the digits of
X
{\displaystyle X}
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Long_year | Long year | Most years have 52 weeks, some have 53, according to ISO8601.
Task
Write a function which determines if a given year is long (53 weeks) or not, and demonstrate it.
| #Quackery | Quackery | [ dup dip
[ 1 1 rot dayofweek 4 = ]
31 12 rot dayofweek 4 = or ] is longyear ( n --> b )
say "Long Years in the 21st Century" cr
cr
100 times
[ 2000 i^ + longyear if
[ 2000 i^ + echo sp ] ] | Give a code snippet in #Quackery
Most years have 52 weeks, some have 53, according to ISO8601.
Task
Write a function which determines if a given year is long (53 weeks) or not, and demonstrate it.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Chernick%27s_Carmichael_numbers | Chernick's Carmichael numbers | In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(4, m) = U(3, m) * (2^2 * 9m + 1)... | #FreeBASIC | FreeBASIC | #include "isprime.bas"
Function PrimalityPretest(k As Integer) As Boolean
Dim As Integer ppp(1 To 8) = {3,5,7,11,13,17,19,23}
For i As Integer = 1 To Ubound(ppp)
If k Mod ppp(i) = 0 Then Return (k <= 23)
Next i
Return True
End Function
Function isChernick(n As Integer, m As Integer) As Boole... | Give a code snippet in #FreeBASIC
In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sleep | Sleep | Task
Write a program that does the following in this order:
Input an amount of time to sleep in whatever units are most natural for your language (milliseconds, seconds, ticks, etc.). This unit should be noted in comments or in a description.
Print "Sleeping..."
Sleep the main thread for the given amount of time.
... | #Jsish | Jsish | /*
Sleep, in Jsish
*/
printf('Sleep time (in milliseconds)? ');
var ms = parseInt(console.input());
puts('Sleeping...');
sleep(ms);
puts('Awake!'); | Give a code snippet in #Jsish
Task
Write a program that does the following in this order:
Input an amount of time to sleep in whatever units are most natural for your language (milliseconds, seconds, ticks, etc.). This unit should be noted in comments or in a description.
Print "Sleeping..."
Sleep the main thread... | christopher/rosetta-code | |
http://rosettacode.org/wiki/URL_encoding | URL encoding | Task
Provide a function or mechanism to convert a provided string into URL encoding representation.
In URL encoding, special characters, control characters and extended characters
are converted into a percent symbol followed by a two digit hexadecimal code,
So a space character encodes into %20 within the string.
Fo... | #ooRexx | ooRexx | sub urlencode {
my $s = shift;
$s =~ s/([^-A-Za-z0-9_.!~*'() ])/sprintf("%%%02X", ord($1))/eg;
$s =~ tr/ /+/;
return $s;
}
print urlencode('http://foo bar/')."\n";
| Give a code snippet in #ooRexx
Task
Provide a function or mechanism to convert a provided string into URL encoding representation.
In URL encoding, special characters, control characters and extended characters
are converted into a percent symbol followed by a two digit hexadecimal code,
So a space character encodes... | 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.
| #11l | 11l | File(filename, ‘w’).write(string) | Give a code snippet in #11l
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/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Tcl | Tcl | package require Tk
proc readPPM {image file} {
$image read $file -format ppm
} | Give a code snippet in #Tcl
Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscal... | 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... | #jq | jq | def church(f; $x; $m):
if $m == 0 then .
elif $m == 1 then $x|f
else church(f; $x; $m - 1)
end; | Give a code snippet in #jq
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 th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/9_billion_names_of_God_the_integer | 9 billion names of God the integer | This task is a variation of the short story by Arthur C. Clarke.
(Solvers should be aware of the consequences of completing this task.)
In detail, to specify what is meant by a “name”:
The integer 1 has 1 name “1”.
The integer 2 has 2 names “1+1”, and “2”.
The integer 3 has 3 names “1+1+1”, “2+1”, ... | #Stata | Stata | mata
function part(n) {
a = J(n,n,.)
for (i=1;i<=n;i++) a[i,1] = a[i,i] = 1
for (i=3;i<=n;i++) {
for (j=2;j<i;j++) a[i,j] = sum(a[i-j,1..min((j,i-j))])
}
return(a)
}
end | Give a code snippet in #Stata
This task is a variation of the short story by Arthur C. Clarke.
(Solvers should be aware of the consequences of completing this task.)
In detail, to specify what is meant by a “name”:
The integer 1 has 1 name “1”.
The integer 2 has 2 names “1+1”, and “2”.
The integer 3 has... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Digital_root | Digital root | The digital root,
X
{\displaystyle X}
, of a number,
n
{\displaystyle n}
, is calculated:
find
X
{\displaystyle X}
as the sum of the digits of
n
{\displaystyle n}
find a new
X
{\displaystyle X}
by summing the digits of
X
{\displaystyle X}
, repeating until
X
{\displ... | #D | D | import std.stdio, std.typecons, std.conv, std.bigint, std.math,
std.traits;
Tuple!(uint, Unqual!T) digitalRoot(T)(in T inRoot, in uint base)
pure nothrow
in {
assert(base > 1);
} body {
Unqual!T root = inRoot.abs;
uint persistence = 0;
while (root >= base) {
auto num = root;
roo... | Give a code snippet in #D
The digital root,
X
{\displaystyle X}
, of a number,
n
{\displaystyle n}
, is calculated:
find
X
{\displaystyle X}
as the sum of the digits of
n
{\displaystyle n}
find a new
X
{\displaystyle X}
by summing the digits of
X
{\displaystyle X}
, repe... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Pythagorean_means | Averages/Pythagorean means | Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ,x_{n})}
for this set of p... | #jq | jq | def amean: add/length;
def logProduct: map(log) | add;
def gmean: (logProduct / length) | exp;
def hmean: length / (map(1/.) | add);
# Tasks:
[range(1;11) ] | [amean, gmean, hmean] as $ans
| ( $ans[],
"amean > gmean > hmean => \($ans[0] > $ans[1] and $ans[1] > $ans[2] )" )
| Give a code snippet in #jq
Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/First-class_functions | First-class functions | A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as retu... | #D | D | void main() {
import std.stdio, std.math, std.typetuple, std.functional;
alias dir = TypeTuple!(sin, cos, x => x ^^ 3);
alias inv = TypeTuple!(asin, acos, cbrt);
// foreach (f, g; staticZip!(dir, inv))
foreach (immutable i, f; dir)
writefln("%6.3f", compose!(f, inv[i])(0.5));
} | Give a code snippet in #D
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other funct... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Square_but_not_cube | Square but not cube | Task
Show the first 30 positive integers which are squares but not cubes of such integers.
Optionally, show also the first 3 positive integers which are both squares and cubes, and mark them as such.
| #PL.2FM | PL/M | 100H: /* CP/M OUTPUT */
BDOS: PROCEDURE (FN, ARG);
DECLARE FN BYTE, ARG ADDRESS;
GO TO 5;
END BDOS;
PRINT$NUMBER: PROCEDURE (N);
DECLARE S (7) BYTE INITIAL ('..... $');
DECLARE (N, P) ADDRESS, C BASED P BYTE;
P = .S(5);
DIGIT:
P = P-1;
C = N MOD 10 + '0';
N = N/10;
IF N > 0 THEN GO... | Give a code snippet in #PL.2FM
Task
Show the first 30 positive integers which are squares but not cubes of such integers.
Optionally, show also the first 3 positive integers which are both squares and cubes, and mark them as such.
| 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.)
| #AmigaE | AmigaE | /* multiline comment
are like C ... */
-> this is a end of line comment | Give a code snippet in #AmigaE
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/Menu | Menu | Task
Given a prompt and a list containing a number of strings of which one is to be selected, create a function that:
prints a textual menu formatted as an index value followed by its corresponding string for each item in the list;
prompts the user to enter a number;
returns the string corresponding to the selecte... | #Java | Java | public static String select(List<String> list, String prompt){
if(list.size() == 0) return "";
Scanner sc = new Scanner(System.in);
String ret = null;
do{
for(int i=0;i<list.size();i++){
System.out.println(i + ": "+list.get(i));
}
System.out.print(prompt);
int... | Give a code snippet in #Java
Task
Given a prompt and a list containing a number of strings of which one is to be selected, create a function that:
prints a textual menu formatted as an index value followed by its corresponding string for each item in the list;
prompts the user to enter a number;
returns the strin... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Program_name | Program name | The task is to programmatically obtain the name used to invoke the program. (For example determine whether the user ran "python hello.py", or "python hellocaller.py", a program importing the code from "hello.py".)
Sometimes a multiline shebang is necessary in order to provide the script name to a language's internal A... | #Java | Java | public class ScriptName {
public static void main(String[] args) {
String program = System.getProperty("sun.java.command").split(" ")[0];
System.out.println("Program: " + program);
}
} | Give a code snippet in #Java
The task is to programmatically obtain the name used to invoke the program. (For example determine whether the user ran "python hello.py", or "python hellocaller.py", a program importing the code from "hello.py".)
Sometimes a multiline shebang is necessary in order to provide the script n... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Play_recorded_sounds | Play recorded sounds | Load at least two prerecorded sounds, and demonstrate as many of these features as you can:
playing them individually and simultaneously
stopping before the end of the sound
looping (preferably glitch-free)
setting the volume of each sound
stereo or 3D positional mixing
performing other actions when marked times... | #PureBasic | PureBasic | InitSound()
; We need this to use Sound functions
UseOGGSoundDecoder()
; Now we can not only load wav sound files, but also ogg encoded ones.
; With movie library more formats can be played (depends on system) but you cannot
; handle them with Sound functions
If Not LoadSound(1,"Path/to/Sound/1.ogg") Or Not LoadSou... | Give a code snippet in #PureBasic
Load at least two prerecorded sounds, and demonstrate as many of these features as you can:
playing them individually and simultaneously
stopping before the end of the sound
looping (preferably glitch-free)
setting the volume of each sound
stereo or 3D positional mixing
perform... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_stability | Sort stability |
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
... | #Wren | Wren | import "/sort" for Cmp, Sort
var data = [ ["UK", "London"], ["US", "New York"], ["US", "Birmingham"], ["UK", "Birmingham"] ]
// for sorting by country
var cmp = Fn.new { |p1, p2| Cmp.string.call(p1[0], p2[0]) }
// for sorting by city
var cmp2 = Fn.new { |p1, p2| Cmp.string.call(p1[1], p2[1]) }
System.print("Ini... | Give a code snippet in #Wren
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/Abundant,_deficient_and_perfect_number_classifications | Abundant, deficient and perfect number classifications | These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficient (OEIS A005100).
if P(n)... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program numberClassif.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see task include a ... | Give a code snippet in #ARM_Assembly
These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as de... | 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... | #Rust | Rust | struct Ant {
x: usize,
y: usize,
dir: Direction
}
#[derive(Clone,Copy)]
enum Direction {
North,
East,
South,
West
}
use Direction::*;
impl Ant {
fn mv(&mut self, vec: &mut Vec<Vec<u8>>) {
let pointer = &mut vec[self.y][self.x];
//change direction
match *poin... | Give a code snippet in #Rust
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 ... | 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
... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI or android 32 bits */
/* program ackermann.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see... | Give a code snippet in #ARM_Assembly
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/Filter | Filter | Task
Select certain elements from an Array into a new Array in a generic way.
To demonstrate, select all even numbers from an Array.
As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.
| #GAP | GAP | # Built-in
Filtered([1 .. 100], IsPrime);
# [ 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 ]
Filtered([1 .. 10], IsEvenInt);
# [ 2, 4, 6, 8, 10 ]
Filtered([1 .. 10], IsOddInt);
# [ 1, 3, 5, 7, 9 ] | Give a code snippet in #GAP
Task
Select certain elements from an Array into a new Array in a generic way.
To demonstrate, select all even numbers from an Array.
As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Aliquot_sequence_classifications | Aliquot sequence classifications | An aliquot sequence of a positive integer K is defined recursively as the first member
being K and subsequent members being the sum of the Proper divisors of the previous term.
If the terms eventually reach 0 then the series for K is said to terminate.
There are several classifications for non termination:
If the s... | #Ring | Ring |
# Project : Aliquot sequence classnifications
see "Rosetta Code - aliquot sequence classnifications" + nl
while true
see "enter an integer: "
give k
k=fabs(floor(number(k)))
if k=0
exit
ok
printas(k)
end
see "program complete."
func printas(k)... | Give a code snippet in #Ring
An aliquot sequence of a positive integer K is defined recursively as the first member
being K and subsequent members being the sum of the Proper divisors of the previous term.
If the terms eventually reach 0 then the series for K is said to terminate.
There are several classifications ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Faulhaber%27s_triangle | Faulhaber's triangle | Named after Johann Faulhaber, the rows of Faulhaber's triangle are the coefficients of polynomials that represent sums of integer powers, which are extracted from Faulhaber's formula:
∑
k
=
1
n
k
p
=
1
p
+
1
∑
j
=
0
p
(
p
+
1
j
)
B
j
n
p
+
1
−
j
{\displaystyle \sum _{k... | #C | C | #include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int binomial(int n, int k) {
int num, denom, i;
if (n < 0 || k < 0 || n < k) return -1;
if (n == 0 || k == 0) return 1;
num = 1;
for (i = k + 1; i <= n; ++i) {
num = num * i;
}
denom = 1;
for ... | Give a code snippet in #C
Named after Johann Faulhaber, the rows of Faulhaber's triangle are the coefficients of polynomials that represent sums of integer powers, which are extracted from Faulhaber's formula:
∑
k
=
1
n
k
p
=
1
p
+
1
∑
j
=
0
p
(
p
+
1
j
)
B
j
n
p
+
1
−
j
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Symmetric_difference | Symmetric difference | Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{\displaystyle (A\cup B)\setminus (A... | #Prolog | Prolog | sym_diff :-
A = ['John', 'Serena', 'Bob', 'Mary', 'Serena'],
B = ['Jim', 'Mary', 'John', 'Jim', 'Bob'],
format('A : ~w~n', [A]),
format('B : ~w~n', [B]),
list_to_set(A, SA),
list_to_set(B, SB),
format('set from A : ~w~n', [SA]),
format('set from B : ~w~n', [SB]),
subtract(SA, SB, DAB... | Give a code snippet in #Prolog
Task
Given two sets A and B, compute
(
A
∖
B
)
∪
(
B
∖
A
)
.
{\displaystyle (A\setminus B)\cup (B\setminus A).}
That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B.
In other words:
(
A
∪
B
)
∖
(
A
∩
B
)
{\di... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available,... | #GUISS | GUISS | Start,Programs,Lotus 123,Type:Bob[downarrow],Kat[downarrow],Sarah[downarrow] | Give a code snippet in #GUISS
This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retri... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/String | Literals/String | Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characters
Here document
Other tasks r... | #MATLAB | MATLAB |
s1 = 'abcd' % simple string
s2 = 'ab''cd' % string containing a single quote
| Give a code snippet in #MATLAB
Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characters
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_largest_left_truncatable_prime_in_a_given_base | Find largest left truncatable prime in a given base | A truncatable prime is one where all non-empty substrings that finish at the end of the number (right-substrings) are also primes when understood as numbers in a particular base. The largest such prime in a given (integer) base is therefore computable, provided the base is larger than 2.
Let's consider what happens in... | #Perl | Perl | use ntheory qw/:all/;
use Math::GMPz;
sub lltp {
my($n, $b, $best) = (shift, Math::GMPz->new(1));
my @v = map { Math::GMPz->new($_) } @{primes($n-1)};
while (@v) {
$best = vecmax(@v);
$b *= $n;
my @u;
foreach my $vi (@v) {
push @u, grep { is_prob_prime($_) } map { $vi + $_*$b } 1 .. $n-1;
... | Give a code snippet in #Perl
A truncatable prime is one where all non-empty substrings that finish at the end of the number (right-substrings) are also primes when understood as numbers in a particular base. The largest such prime in a given (integer) base is therefore computable, provided the base is larger than 2.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Time_a_function | Time a function | Task
Write a program which uses a timer (with the least granularity available
on your system) to time how long a function takes to execute.
Whenever possible, use methods which measure only the processing time used
by the current process; instead of the difference in system time
between start and finish, which could ... | #ACL2 | ACL2 | (time$ (nthcdr 9999999 (take 10000000 nil))) | Give a code snippet in #ACL2
Task
Write a program which uses a timer (with the least granularity available
on your system) to time how long a function takes to execute.
Whenever possible, use methods which measure only the processing time used
by the current process; instead of the difference in system time
between ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Spiral_matrix | Spiral matrix | Task
Produce a spiral array.
A spiral array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you go around the edges of the array spiraling inwards.
For example, given 5, produce this array:
0 1 2 3 4
15 16 17 18 5
14 23 24 19 6
13 22 21 ... | #PARI.2FGP | PARI/GP | spiral(dim) = {
my (M = matrix(dim, dim), p = s = 1, q = i = 0);
for (n=1, dim,
for (b=1, dim-n+1, M[p,q+=s] = i; i++);
for (b=1, dim-n, M[p+=s,q] = i; i++);
s = -s;
);
M
} | Give a code snippet in #PARI.2FGP
Task
Produce a spiral array.
A spiral array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you go around the edges of the array spiraling inwards.
For example, given 5, produce this array:
0 1 2 3 4
15 1... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Perfect_shuffle | Perfect shuffle | A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on:
7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠ 8♠ 9♠
J♠ Q♠ K♠→7♠ J♠ 8♠ Q♠ 9♠ K♠
When you ... | #zkl | zkl | fcn perfectShuffle(numCards){
deck,shuffle,n,N:=numCards.pump(List),deck,0,numCards/2;
do{ shuffle=shuffle[0,N].zip(shuffle[N,*]).flatten(); n+=1 }
while(deck!=shuffle);
n
}
foreach n in (T(8,24,52,100,1020,1024,10000)){
println("%5d : %d".fmt(n,perfectShuffle(n)));
} | Give a code snippet in #zkl
A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on:
7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠ 8♠ 9♠
J♠ Q♠ K♠→... | 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
| #PicoLisp | PicoLisp | (class +Point)
# x y
(dm T (X Y)
(=: x (or X 0))
(=: y (or Y 0)) )
(dm print> ()
(prinl "Point " (: x) "," (: y)) )
(class +Circle +Point)
# r
(dm T (X Y R)
(super X Y)
(=: r (or R 0)) )
(dm print> ()
(prinl "Circle " (: x) "," (: y) "," (: r)) ) | Give a code snippet in #PicoLisp
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/Keyboard_macros | Keyboard macros | Show how to link user defined methods to user defined keys.
An example of this is the facility provided by emacs for key bindings.
These key bindings may be application-specific or system-wide; state which you have done.
| #Clojure | Clojure |
(ns hello-seesaw.core
(:use seesaw.core))
(defn -main [& args]
(invoke-later
(-> (frame
:listen [:key-pressed (fn [e] (println (.getKeyChar e) " key pressed"))]
:on-close :exit)
pack!
show!)))
| Give a code snippet in #Clojure
Show how to link user defined methods to user defined keys.
An example of this is the facility provided by emacs for key bindings.
These key bindings may be application-specific or system-wide; state which you have done.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Guess_the_number/With_feedback | Guess the number/With feedback | Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to... | #C.2B.2B | C++ | #include <iostream>
#include <cstdlib>
#include <ctime>
int main()
{
std::srand(std::time(0));
int lower, upper, guess;
std::cout << "Enter lower limit: ";
std::cin >> lower;
std::cout << "Enter upper limit: ";
std::cin >> upper;
int random_number = lower + std::rand() % ((upper + 1) - low... | Give a code snippet in #C.2B.2B
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Color_quantization | Color quantization | full color
Example: Gimp 16 color
Color quantization is the process of reducing number of colors used in an image while trying to maintain the visual appearance of the original image. In general, it is a form of cluster analysis, if each RGB color value is considered as a coordinate triple in the 3D colorspace. There... | #Nim | Nim | import algorithm
import nimPNG
type
Channel {.pure.} = enum R, G, B
QItem = tuple
color: array[Channel, byte] # Color of the pixel.
index: int # Position of pixel in the sequential sequence.
#---------------------------------------------------------------------------------------... | Give a code snippet in #Nim
full color
Example: Gimp 16 color
Color quantization is the process of reducing number of colors used in an image while trying to maintain the visual appearance of the original image. In general, it is a form of cluster analysis, if each RGB color value is considered as a coordinate tripl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler%27s_identity | Euler's identity |
This page uses content from Wikipedia. The original article was at Euler's_identity. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In mathematics, Euler's identity is the equality:
... | #C.2B.2B | C++ | #include <iostream>
#include <complex>
int main() {
std::cout << std::exp(std::complex<double>(0.0, M_PI)) + 1.0 << std::endl;
return 0;
} | Give a code snippet in #C.2B.2B
This page uses content from Wikipedia. The original article was at Euler's_identity. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In mathematics, Euler's identit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Curzon_numbers | Curzon numbers | A Curzon number is defined to be a positive integer n for which 2n + 1 is evenly divisible by 2 × n + 1.
Generalized Curzon numbers are those where the positive integer n, using a base integer k, satisfy the condition that kn + 1 is evenly divisible by k × n + 1.
Base here does not imply the radix of the counting sys... | #Vlang | Vlang | import math.big
fn main() {
zero := big.zero_int
one := big.one_int
for k := i64(2); k <= 10; k += 2 {
bk := big.integer_from_i64(k)
println("The first 50 Curzon numbers using a base of $k:")
mut count := 0
mut n := i64(1)
mut pow := big.integer_from_i64(k)
... | Give a code snippet in #Vlang
A Curzon number is defined to be a positive integer n for which 2n + 1 is evenly divisible by 2 × n + 1.
Generalized Curzon numbers are those where the positive integer n, using a base integer k, satisfy the condition that kn + 1 is evenly divisible by k × n + 1.
Base here does not impl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sierpinski_triangle | Sierpinski triangle | Task
Produce an ASCII representation of a Sierpinski triangle of order N.
Example
The Sierpinski triangle of order 4 should look like this:
*
* *
* *
* * * *
* *
* * * *
... | #AutoHotkey | AutoHotkey | Loop 6
MsgBox % Triangle(A_Index)
Triangle(n,x=0,y=1) { ; Triangle(n) -> string of dots and spaces of Sierpinski triangle
Static t, l ; put chars in a static string
If (x < 1) { ; when called with one parameter
l := 2*x := 1<<(n-1) ... | Give a code snippet in #AutoHotkey
Task
Produce an ASCII representation of a Sierpinski triangle of order N.
Example
The Sierpinski triangle of order 4 should look like this:
*
* *
* *
* * * *
* *... | 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... | #Kotlin | Kotlin | // version 1.0.6
/* testing on Windows 10 which needs administrative privileges
to rename files in the root */
import java.io.File
fun main(args: Array<String>) {
val oldPaths = arrayOf("input.txt", "docs", "c:\\input.txt", "c:\\docs")
val newPaths = arrayOf("output.txt", "mydocs", "c:\\output.txt", "c... | Give a code snippet in #Kotlin
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 r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #QB64 | QB64 |
'dictionary is not native data type of QB64
' here a dictionary engine using a string to store data
Dim Shared Skey As String * 1, SValue As String * 1, EValue As String * 1
Skey = Chr$(0)
SValue = Chr$(1)
EValue = Chr$(255)
'Demo area---------------->
Dim MyDictionary As String
If ChangeValue(MyDictionary, "a", ... | Give a code snippet in #QB64
Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Comp... | 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... | #Maple | Maple | i := 42:
count := 0:
while(count < 42) do
i := i+1:
if type(i,prime) then
count := count + 1:
printf("n=%-2d %19d\n", count,i):
i := 2*i -1:
end if:
end do: | Give a code snippet in #Maple
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/Anonymous_recursion | Anonymous recursion | While implementing a recursive function, it often happens that we must resort to a separate helper function to handle the actual recursion.
This is usually the case when directly calling the current function would waste too many resources (stack space, execution time), causing unwanted side-effects, and/or the f... | #PARI.2FGP | PARI/GP | Fib(n)={
my(F=(k,f)->if(k<2,k,f(k-1,f)+f(k-2,f)));
if(n<0,(-1)^(n+1),1)*F(abs(n),F)
}; | Give a code snippet in #PARI.2FGP
While implementing a recursive function, it often happens that we must resort to a separate helper function to handle the actual recursion.
This is usually the case when directly calling the current function would waste too many resources (stack space, execution time), causing un... | 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.
| #AutoHotkey | AutoHotkey | #i:: ; (Optional) Assigns a hotkey to display window info, Windows+i
MouseGetPos, x, y ; Gets x/y pos relative to active window
WinGetActiveTitle, WinTitle ; Gets active window title
Traytip, Mouse position, x: %x%`ny: %y%`rWindow: %WinTitle%, 4 ; Displays the info as a Traytip for 4 seconds
return | Give a code snippet in #AutoHotkey
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/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... | #Wren | Wren | class Span {
construct new(r) {
if (r.type != Range || !r.isInclusive) Fiber.abort("Argument must be an inclusive range.")
_low = r.from
_high = r.to
if (_low > _high) {
_low = r.to
_high = r.from
}
}
low { _low }
high { _high }
co... | Give a code snippet in #Wren
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 ... | 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 ... | #FALSE | FALSE | condition[body]? | Give a code snippet in #FALSE
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loop_over_multiple_arrays_simultaneously | Loop over multiple arrays simultaneously | Task
Loop over multiple arrays (or lists or tuples or whatever they're called in
your language) and display the i th element of each.
Use your language's "for each" loop if it has one, otherwise iterate
through the collection in order with some other loop.
For this example, loop over the arrays:
... | #Ruby | Ruby | ['a','b','c'].zip(['A','B','C'], [1,2,3]) {|i,j,k| puts "#{i}#{j}#{k}"} | Give a code snippet in #Ruby
Task
Loop over multiple arrays (or lists or tuples or whatever they're called in
your language) and display the i th element of each.
Use your language's "for each" loop if it has one, otherwise iterate
through the collection in order with some other loop.
For this examp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Send_email | Send email | Task
Write a function to send an email.
The function should have parameters for setting From, To and Cc addresses; the Subject, and the message text, and optionally fields for the server name and login details.
If appropriate, explain what notifications of problems/success are given.
Solutions using libraries or f... | #C.2B.2B | C++ | // on Ubuntu: sudo apt-get install libpoco-dev
// or see http://pocoproject.org/
// compile with: g++ -Wall -O3 send-mail-cxx.C -lPocoNet -lPocoFoundation
#include <cstdlib>
#include <iostream>
#include <Poco/Net/SMTPClientSession.h>
#include <Poco/Net/MailMessage.h>
using namespace Poco::Net;
int main (int argc,... | Give a code snippet in #C.2B.2B
Task
Write a function to send an email.
The function should have parameters for setting From, To and Cc addresses; the Subject, and the message text, and optionally fields for the server name and login details.
If appropriate, explain what notifications of problems/success are given... | 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... | #D | D | import std.stdio;
void main()
{
auto lp = File("/dev/lp0", "w");
lp.writeln("Hello World!");
}
| Give a code snippet in #D
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 sys... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ascending_primes | Ascending primes | Generate and show all primes with strictly ascending decimal digits.
Aside: Try solving without peeking at existing solutions. I had a weird idea for generating
a prime sieve faster, which needless to say didn't pan out. The solution may be p(r)etty trivial
but generating them quickly is at least mildly interesting.
T... | #jq | jq |
# Output: the stream of ascending primes, in order
def ascendingPrimes:
# Generate the stream of primes beginning with the digit .
# and with strictly ascending digits, without regard to order
def generate:
# strings
def g:
. as $first
| tonumber as $n
| select($n <= 9)
| $first,... | Give a code snippet in #jq
Generate and show all primes with strictly ascending decimal digits.
Aside: Try solving without peeking at existing solutions. I had a weird idea for generating
a prime sieve faster, which needless to say didn't pan out. The solution may be p(r)etty trivial
but generating them quickly is at... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Make_directory_path | Make directory path | Task
Create a directory and any missing parents.
This task is named after the posix mkdir -p command, and several libraries which implement the same behavior.
Please implement a function of a single path string (for example ./path/to/dir) which has the above side-effect.
If the directory already exists, return succe... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | mkdirp[path_] := Quiet[CreateDirectory[path,{CreateIntermediateDirectories->True}],{CreateDirectory::filex}] | Give a code snippet in #Mathematica.2FWolfram_Language
Task
Create a directory and any missing parents.
This task is named after the posix mkdir -p command, and several libraries which implement the same behavior.
Please implement a function of a single path string (for example ./path/to/dir) which has the above si... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Naive | Verify distribution uniformity/Naive | This task is an adjunct to Seven-sided dice from five-sided dice.
Task
Create a function to check that the random integers returned from a small-integer generator function have uniform distribution.
The function should take as arguments:
The function (or object) producing random integers.
The number of times ... | #Julia | Julia | using Printf
function distcheck(f::Function, rep::Int=10000, Δ::Int=3)
smpl = f(rep)
counts = Dict(k => count(smpl .== k) for k in unique(smpl))
expected = rep / length(counts)
lbound = expected * (1 - 0.01Δ)
ubound = expected * (1 + 0.01Δ)
noobs = count(x -> !(lbound ≤ x ≤ ubound), values(cou... | Give a code snippet in #Julia
This task is an adjunct to Seven-sided dice from five-sided dice.
Task
Create a function to check that the random integers returned from a small-integer generator function have uniform distribution.
The function should take as arguments:
The function (or object) producing random ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hash_from_two_arrays | Hash from two arrays | Task
Using two Arrays of equal length, create a Hash object
where the elements from one array (the keys) are linked
to the elements of the other (the values)
Related task
Associative arrays/Creation
| #Pascal | Pascal | program HashFromTwoArrays (Output);
uses
contnrs;
var
keys: array[1..3] of string = ('a', 'b', 'c');
values: array[1..3] of integer = ( 1, 2, 3 );
hash: TFPDataHashTable;
i: integer;
begin
hash := TFPDataHashTable.Create;
for i := low(keys) to high(keys) do
hash.add(keys[i], @value... | Give a code snippet in #Pascal
Task
Using two Arrays of equal length, create a Hash object
where the elements from one array (the keys) are linked
to the elements of the other (the values)
Related task
Associative arrays/Creation
| 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 ... | #Ruby | Ruby |
# frozen_string_literal: true
def setup
sketch_title 'Pythagoras Tree'
background(255)
stroke(0, 255, 0)
tree(width / 2.3, height, width / 1.8, height, 10)
end
def tree(x1, y1, x2, y2, depth)
return if depth <= 0
dx = (x2 - x1)
dy = (y1 - y2)
x3 = (x2 - dy)
y3 = (y2 - dx)
x4 = (x1 - dy)
... | Give a code snippet in #Ruby
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/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... | #Wren | Wren | import "/ioutil" for FileUtil
FileUtil.move("input.txt", "output.txt")
FileUtil.move("/input.txt", "/output.txt") | Give a code snippet in #Wren
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 rig... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Null_object | Null object |
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your language by checking to see if an ob... | #Smalltalk | Smalltalk | object isNil ifTrue: [ "true block" ]
ifFalse: [ "false block" ].
nil isNil ifTrue: [ 'true!' displayNl ]. "output: true!"
foo isNil ifTrue: [ 'ouch' displayNl ].
x := (foo == nil).
x := foo isNil | Give a code snippet in #Smalltalk
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your l... | 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 ... | #PARI.2FGP | PARI/GP | meanAngle(v)=atan(sum(i=1,#v,sin(v[i]))/sum(i=1,#v,cos(v[i])))%(2*Pi)
meanDegrees(v)=meanAngle(v*Pi/180)*180/Pi
apply(meanDegrees,[[350, 10], [90, 180, 270, 360], [10, 20, 30]]) | Give a code snippet in #PARI.2FGP
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Keyboard_input/Keypress_check | Keyboard input/Keypress check |
Determine if a key has been pressed and store this in a variable.
If no key has been pressed, the program should continue without waiting.
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | i = {};
EventHandler[Panel[Dynamic[i],
ImageSize -> {300, 300}], {"KeyDown" :>
AppendTo[i, CurrentValue["EventKey"]]}] | Give a code snippet in #Mathematica.2FWolfram_Language
Determine if a key has been pressed and store this in a variable.
If no key has been pressed, the program should continue without waiting.
| christopher/rosetta-code |
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