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/Apply_a_callback_to_an_array | Apply a callback to an array | Task
Take a combined set of elements and apply a function to each element.
| #Jsish | Jsish | /* Apply callback, in Jsish using array.map() */
;[1, 2, 3, 4, 5].map(function(v,i,a) { return v * v; });
/*
=!EXPECTSTART!=
[1, 2, 3, 4, 5].map(function(v,i,a) { return v * v; }) ==> [ 1, 4, 9, 16, 25 ]
=!EXPECTEND!=
*/ | Give a code snippet in #Jsish
Task
Take a combined set of elements and apply a function to each element.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_control_codes_and_extended_characters_from_a_string | Strip control codes and extended characters from a string | Task
Strip control codes and extended characters from a string.
The solution should demonstrate how to achieve each of the following results:
a string with control codes stripped (but extended characters not stripped)
a string with control codes and extended characters stripped
In ASCII, the control codes ... | #11l | 11l | F stripped(s)
R s.filter(i -> Int(i.code) C 32..126).join(‘’)
print(stripped("\ba\u0000b\n\rc\fd\xc3")) | Give a code snippet in #11l
Task
Strip control codes and extended characters from a string.
The solution should demonstrate how to achieve each of the following results:
a string with control codes stripped (but extended characters not stripped)
a string with control codes and extended characters stripped
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Forward_difference | Forward difference | Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer elem... | #Raku | Raku | sub dif(@array [$, *@tail]) { @tail Z- @array }
sub difn($array, $n) { ($array, &dif ... *)[$n] } | Give a code snippet in #Raku
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catamorphism | Catamorphism | Reduce is a function or method that is used to take the values in an array or a list and apply a function to successive members of the list to produce (or reduce them to), a single value.
Task
Show how reduce (or foldl or foldr etc), work (or would be implemented) in your language.
See also
Wikipedia article: ... | #Fortran | Fortran | SUBROUTINE FOLD(t,F,i,ist,lst)
INTEGER t
BYNAME F
DO i = ist,lst
t = F
END DO
END SUBROUTINE FOLD !Result in temp.
temp = a(1); CALL FOLD(temp,temp*a(i),i,2,N) | Give a code snippet in #Fortran
Reduce is a function or method that is used to take the values in an array or a list and apply a function to successive members of the list to produce (or reduce them to), a single value.
Task
Show how reduce (or foldl or foldr etc), work (or would be implemented) in your language.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_entire_file | Read entire file | Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished incrementally instead
(in which case... | #C.23 | C# | using System.IO;
class Program
{
static void Main(string[] args)
{
var fileContents = File.ReadAllText("c:\\autoexec.bat");
// Can optionally take a second parameter to specify the encoding, e.g. File.ReadAllText("c:\\autoexec.bat", Encoding.UTF8)
}
} | Give a code snippet in #C.23
Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished increm... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Almost_prime | Almost prime | A k-Almost-prime is a natural number
n
{\displaystyle n}
that is the product of
k
{\displaystyle k}
(possibly identical) primes.
Example
1-almost-primes, where
k
=
1
{\displaystyle k=1}
, are the prime numbers themselves.
2-almost-primes, where
k
=
2
{\displaystyl... | #Seed7 | Seed7 | $ include "seed7_05.s7i";
const func boolean: kprime (in var integer: number, in integer: k) is func
result
var boolean: kprime is FALSE;
local
var integer: p is 2;
var integer: f is 0;
begin
while f < k and p * p <= number do
while number rem p = 0 do
number := number div p;
... | Give a code snippet in #Seed7
A k-Almost-prime is a natural number
n
{\displaystyle n}
that is the product of
k
{\displaystyle k}
(possibly identical) primes.
Example
1-almost-primes, where
k
=
1
{\displaystyle k=1}
, are the prime numbers themselves.
2-almost-primes, wh... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Roman_numerals/Decode | Roman numerals/Decode | Task
Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer.
You don't need to validate the form of the Roman numeral.
Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately,
starting with the leftmost decima... | #C | C | #include <stdio.h>
int digits[26] = { 0, 0, 100, 500, 0, 0, 0, 0, 1, 1, 0, 50, 1000, 0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 10, 0, 0 };
/* assuming ASCII, do upper case and get index in alphabet. could also be
inline int VALUE(char x) { return digits [ (~0x20 & x) - 'A' ]; }
if you think macros are evil */
#defin... | Give a code snippet in #C
Task
Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer.
You don't need to validate the form of the Roman numeral.
Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately,
starti... | 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... | #R | R | beautyProblem <- function(n)
{
wakeCount <- headCount <- 0
for(i in seq_len(n))
{
wakeCount <- wakeCount + 1
if(sample(c("H", "T"), 1) == "H") headCount <- headCount + 1 else wakeCount <- wakeCount + 1
}
headCount/wakeCount
}
print(beautyProblem(10000000)) | Give a code snippet in #R
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catamorphism | Catamorphism | Reduce is a function or method that is used to take the values in an array or a list and apply a function to successive members of the list to produce (or reduce them to), a single value.
Task
Show how reduce (or foldl or foldr etc), work (or would be implemented) in your language.
See also
Wikipedia article: ... | #PicoLisp | PicoLisp | (de reduce ("Fun" "Lst")
(let "A" (car "Lst")
(for "N" (cdr "Lst")
(setq "A" ("Fun" "A" "N")) )
"A" ) )
(println
(reduce + (1 2 3 4 5))
(reduce * (1 2 3 4 5)) )
(bye) | Give a code snippet in #PicoLisp
Reduce is a function or method that is used to take the values in an array or a list and apply a function to successive members of the list to produce (or reduce them to), a single value.
Task
Show how reduce (or foldl or foldr etc), work (or would be implemented) in your language.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers | Luhn test of credit card numbers | The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits.
Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test:
Reverse the order of the digits in the number.
Tak... | #Go | Go | package main
import (
"fmt"
"strings"
)
const input = `49927398716
49927398717
1234567812345678
1234567812345670`
var t = [...]int{0, 2, 4, 6, 8, 1, 3, 5, 7, 9}
func luhn(s string) bool {
odd := len(s) & 1
var sum int
for i, c := range s {
if c < '0' || c > '9' {
return f... | Give a code snippet in #Go
The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits.
Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test:
Reverse the order of th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Haskell | Haskell | module Cholesky (Arr, cholesky) where
import Data.Array.IArray
import Data.Array.MArray
import Data.Array.Unboxed
import Data.Array.ST
type Idx = (Int,Int)
type Arr = UArray Idx Double
-- Return the (i,j) element of the lower triangular matrix. (We assume the
-- lower array bound is (0,0).)
get :: Arr -> Arr -> ... | Give a code snippet in #Haskell
Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be inte... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Real_constants_and_functions | Real constants and functions | Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "magnitude")
floor (largest ... | #C | C | #include <math.h>
M_E; /* e - not standard but offered by most implementations */
M_PI; /* pi - not standard but offered by most implementations */
sqrt(x); /* square root--cube root also available in C99 (cbrt) */
log(x); /* natural logarithm--log base 10 also available (log10) */
exp(x); /* exponential */
abs(x); /... | Give a code snippet in #C
Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "magni... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Substring | Substring |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #ALGOL_68 | ALGOL 68 | main: (
STRING s = "abcdefgh";
INT n = 2, m = 3;
CHAR char = "d";
STRING chars = "cd";
printf(($gl$, s[n:n+m-1]));
printf(($gl$, s[n:]));
printf(($gl$, s[:UPB s-1]));
INT pos;
char in string("d", pos, s);
printf(($gl$, s[pos:pos+m-1]));
string in string("de", pos, s);
printf(($gl$, s[pos:... | Give a code snippet in #ALGOL_68
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operatio... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Palindrome_detection | Palindrome detection | A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as a wrapper to the first) which ... | #Maple | Maple |
with(StringTools):
IsPalindrome("ingirumimusnocteetconsumimurigni");
IsPalindrome("In girum imus nocte et consumimur igni");
IsPalindrome(LowerCase(DeleteSpace("In girum imus nocte et consumimur igni")));
| Give a code snippet in #Maple
A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Shell_one-liner | Shell one-liner | Task
Show how to specify and execute a short program in the language from a command shell, where the input to the command shell is only one line in length.
Avoid depending on the particular shell or operating system used as much as is reasonable; if the language has notable implementations which have different comman... | #Frink | Frink | $ frink -e "factorFlat[2^67-1]" | Give a code snippet in #Frink
Task
Show how to specify and execute a short program in the language from a command shell, where the input to the command shell is only one line in length.
Avoid depending on the particular shell or operating system used as much as is reasonable; if the language has notable implementati... | 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 ... | #Stata | Stata | function spiral_mat(n) {
a = J(n*n, 1, 1)
u = J(n, 1, -n)
v = J(n, 1, 1)
for (k=(i=n)-1; k>=1; i=i+2*k--) {
j = 1..k
a[j:+i] = u[j] = -u[j]
a[j:+(i+k)] = v[j] = -v[j]
}
return(rowshape(invorder(runningsum(a)),n):-1)
}
spiral_mat(5)
1 2 3 4 5
+--------------------------+
1 | 0 ... | Give a code snippet in #Stata
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Probabilistic_choice | Probabilistic choice | Given a mapping between items and their required probability of occurrence, generate a million items randomly subject to the given probabilities and compare the target probability of occurrence versus the generated values.
The total of all the probabilities should equal one. (Because floating point arithmetic is invol... | #Fortran | Fortran | PROGRAM PROBS
IMPLICIT NONE
INTEGER, PARAMETER :: trials = 1000000
INTEGER :: i, j, probcount(8) = 0
REAL :: expected(8), mapping(8), rnum
CHARACTER(6) :: items(8) = (/ "aleph ", "beth ", "gimel ", "daleth", "he ", "waw ", "zayin ", "heth " /)
expected(1:7) = (/ (1.0/i, i=5,11) /)
expected(8)... | Give a code snippet in #Fortran
Given a mapping between items and their required probability of occurrence, generate a million items randomly subject to the given probabilities and compare the target probability of occurrence versus the generated values.
The total of all the probabilities should equal one. (Because f... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Take_notes_on_the_command_line | Take notes on the command line | Take notes on the command line is part of Short Circuit's Console Program Basics selection.
Invoking NOTES without commandline arguments displays the current contents of the local NOTES.TXT if it exists.
If NOTES has arguments, the current date and time are appended to the local NOTES.TXT followed by a newline.
Then al... | #Euphoria | Euphoria | constant cmd = command_line()
constant filename = "notes.txt"
integer fn
object line
sequence date_time
if length(cmd) < 3 then
fn = open(filename,"r")
if fn != -1 then
while 1 do
line = gets(fn)
if atom(line) then
exit
end if
puts(1,line... | Give a code snippet in #Euphoria
Take notes on the command line is part of Short Circuit's Console Program Basics selection.
Invoking NOTES without commandline arguments displays the current contents of the local NOTES.TXT if it exists.
If NOTES has arguments, the current date and time are appended to the local NOTES.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as t... | #Factor | Factor | USE: grouping
all-equal? | Give a code snippet in #Factor
Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Perfect_numbers | Perfect numbers | Write a function which says whether a number is perfect.
A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself.
Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself).
Note: The faster Luca... | #zkl | zkl | fcn isPerfectNumber1(n)
{ n == [1..n-1].filter('wrap(i){ n % i == 0 }).sum(); } | Give a code snippet in #zkl
Write a function which says whether a number is perfect.
A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself.
Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself).... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #M2000_Interpreter | M2000 Interpreter |
A$=""
Print A$<>"", A$="", Len(A$)=0
| Give a code snippet in #M2000_Interpreter
Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not e... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Clear_the_screen | Terminal control/Clear the screen | Task
Clear the terminal window.
| #Comal | Comal | PAGE | Give a code snippet in #Comal
Task
Clear the terminal window.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
... | #beeswax | beeswax | > q
>@F5~%"d@F{ > @F q
_1>F3~%'d`Fizz`@F5~%'d >`Buzz`@FNp
;bL@~.~4~.5~5@ P< | Give a code snippet in #beeswax
Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBu... | 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
... | #EasyLang | EasyLang | func ackerm m n . r .
if m = 0
r = n + 1
elif n = 0
call ackerm m - 1 1 r
else
call ackerm m n - 1 h
call ackerm m - 1 h r
.
.
call ackerm 3 6 r
print r | Give a code snippet in #EasyLang
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/Natural_sorting | Natural sorting |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Fortran | Fortran |
MODULE STASHTEXTS !Using COMMON is rather more tedious.
INTEGER MSG,KBD !I/O unit numbers.
DATA MSG,KBD/6,5/ !Output, input.
INTEGER LSTASH,NSTASH,MSTASH !Prepare a common text stash.
PARAMETER (LSTASH = 2468, MSTASH = 234) !LSTASH characters for MSTASH texts.
INTEGER IS... | Give a code snippet in #Fortran
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Word_frequency | Word frequency | Task
Given a text file and an integer n, print/display the n most
common words in the file (and the number of their occurrences) in decreasing frequency.
For the purposes of this task:
A word is a sequence of one or more contiguous letters.
You are free to define what a letter is.
Undersc... | #KAP | KAP | ∇ stats (file) {
content ← "[\\h,.\"'\n-]+" regex:split unicode:toLower io:readFile file
sorted ← (⍋⊇⊢) content
selection ← 1,2≢/sorted
words ← selection / sorted
{⍵[10↑⍒⍵[;1];]} words ,[0.5] ≢¨ sorted ⊂⍨ +\selection
} | Give a code snippet in #KAP
Task
Given a text file and an integer n, print/display the n most
common words in the file (and the number of their occurrences) in decreasing frequency.
For the purposes of this task:
A word is a sequence of one or more contiguous letters.
You are free to define what... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pascal%27s_triangle | Pascal's triangle | Pascal's triangle is an arithmetic and geometric figure often associated with the name of Blaise Pascal, but also studied centuries earlier in India, Persia, China and elsewhere.
Its first few rows look like this:
1
1 1
1 2 1
1 3 3 1
where each element of each row is either 1 or the sum of the two elemen... | #Oz | Oz | declare
fun {NextLine Xs}
{List.zip 0|Xs {Append Xs [0]}
fun {$ Left Right}
Left + Right
end}
end
fun {Triangle N}
{List.take {Iterate [1] NextLine} N}
end
fun lazy {Iterate I F}
I|{Iterate {F I} F}
end
%% Only works nicely for N =< 5.
proc {PrintTriangle T}
... | Give a code snippet in #Oz
Pascal's triangle is an arithmetic and geometric figure often associated with the name of Blaise Pascal, but also studied centuries earlier in India, Persia, China and elsewhere.
Its first few rows look like this:
1
1 1
1 2 1
1 3 3 1
where each element of each row is either 1 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer cou... | #Icon_and_Unicon | Icon and Unicon | procedure main()
every A := ![ ["the three truths","th"], ["ababababab","abab"] ] do
write("The string ",image(A[2])," occurs as a non-overlapping substring ",
countSubstring!A , " times in ",image(A[1]))
end
procedure countSubstring(s1,s2) #: return count of non-overlapping substrings
c := 0
s... | Give a code snippet in #Icon_and_Unicon
Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searche... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Inheritance/Multiple | Inheritance/Multiple | Multiple inheritance allows to specify that one class is a subclass of several other classes.
Some languages allow multiple inheritance for arbitrary classes, others restrict it to interfaces, some don't allow it at all.
Task
Write two classes (or interfaces) Camera and MobilePhone, then write a class Camer... | #Lingo | Lingo | -- parent script "Camera"
property resolution
on new (me)
me.resolution = "1024x768"
return me
end
on snap (me)
put "SNAP!"
end | Give a code snippet in #Lingo
Multiple inheritance allows to specify that one class is a subclass of several other classes.
Some languages allow multiple inheritance for arbitrary classes, others restrict it to interfaces, some don't allow it at all.
Task
Write two classes (or interfaces) Camera and MobilePh... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_the_missing_permutation | Find the missing permutation | ABCD
CABD
ACDB
DACB
BCDA
ACBD
ADCB
CDAB
DABC
BCAD
CADB
CDBA
... | #XPL0 | XPL0 | code HexIn=26, HexOut=27;
int P, I;
[P:= 0;
for I:= 1 to 24-1 do P:= P xor HexIn(1);
HexOut(0, P);
] | Give a code snippet in #XPL0
ABCD
CABD
ACDB
DACB
BCDA
ACBD
ADCB
CDAB
DABC
BCAD
CADB
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed ... | #PowerShell | PowerShell |
function Read-ArrayIndex ([string]$Prompt = "Enter an integer greater than zero")
{
[int]$inputAsInteger = 0
while (-not [Int]::TryParse(([string]$inputString = Read-Host $Prompt), [ref]$inputAsInteger))
{
$inputString = Read-Host "Enter an integer greater than zero"
}
if ($inputAsInte... | Give a code snippet in #PowerShell
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Factors_of_an_integer | Factors of an integer |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #Lua | Lua | function Factors( n )
local f = {}
for i = 1, n/2 do
if n % i == 0 then
f[#f+1] = i
end
end
f[#f+1] = n
return f
end | Give a code snippet in #Lua
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Co... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Primorial_numbers | Primorial numbers | Primorial numbers are those formed by multiplying successive prime numbers.
The primorial number series is:
primorial(0) = 1 (by definition)
primorial(1) = 2 (2)
primorial(2) = 6 (2×3)
primorial(3) = 30 (2×3×5)
primorial(4) = 210 (2×3×5×... | #Elixir | Elixir |
defmodule SieveofEratosthenes do
def init(lim) do
find_primes(2,lim,(2..lim))
end
def find_primes(count,lim,nums) when (count * count) > lim do
nums
end
def find_primes(count,lim,nums) when (count * count) <= lim do
find_primes(count+1,lim,Enum.reject(nums,&(rem(&1,count) == 0 and &1 > count... | Give a code snippet in #Elixir
Primorial numbers are those formed by multiplying successive prime numbers.
The primorial number series is:
primorial(0) = 1 (by definition)
primorial(1) = 2 (2)
primorial(2) = 6 (2×3)
primorial(3) = 30 (2×3×5)
prim... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catalan_numbers | Catalan numbers | Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
for
n
≥
0.
{\displaystyle C... | #ALGOL_68 | ALGOL 68 | # calculate the first few catalan numbers, using LONG INT values #
# (64-bit quantities in Algol 68G which can handle up to C23) #
# returns n!/k! #
PROC factorial over factorial = ( INT n, k )LONG INT:
IF k > n THEN 0
ELIF k =... | Give a code snippet in #ALGOL_68
Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Extend_your_language | Extend your language | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Some programming languages allow you to extend the language. While this can be done to a certain degree in most languages (e.g. by using macros), other langua... | #TXR | TXR | (defmacro if2 (cond1 cond2 both first second . neither)
(let ((res1 (gensym))
(res2 (gensym)))
^(let ((,res1 ,cond1)
(,res2 ,cond2))
(cond ((and ,res1 ,res2) ,both)
(,res1 ,first)
(,res2 ,second)
(t ,*neither)... | Give a code snippet in #TXR
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Some programming languages allow you to extend the language. While this can be done to a certain degree in most languages (e.g. b... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dinesman%27s_multiple-dwelling_problem | Dinesman's multiple-dwelling problem | Task
Solve Dinesman's multiple dwelling problem but in a way that most naturally follows the problem statement given below.
Solutions are allowed (but not required) to parse and interpret the problem text, but should remain flexible and should state what changes to the problem text are allowed. Flexibility and ease of... | #jq | jq | # Input: an array representing the apartment house, with null at a
# particular position signifying that the identity of the occupant
# there has not yet been determined.
# Output: an elaboration of the input array but including person, and
# satisfying cond, where . in cond refers to the placement of person
de... | Give a code snippet in #jq
Task
Solve Dinesman's multiple dwelling problem but in a way that most naturally follows the problem statement given below.
Solutions are allowed (but not required) to parse and interpret the problem text, but should remain flexible and should state what changes to the problem text are allo... | 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.
| #Phix | Phix | include pGUI.e
function C_Keyed(Ihandle /*ih*/, atom /*c*/)
-- (Note without K_c below this does not respond to 'c', just 'C')
?"you pressed C"
return IUP_DEFAULT
end function
procedure F2_keyed()
?"you pressed F2"
end procedure
function key_cb(Ihandle /*ih*/, atom c)
if c=K_F2 then F2_keyed()
... | Give a code snippet in #Phix
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/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... | #J | J |
tacit_loop =: _1&(>:@:{`[`]})@:(, (1&p: # _1 2&p.)@:{:)@:]^:(0 ~: (>: #))^:_ x:
| Give a code snippet in #J
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/Bitmap/B%C3%A9zier_curves/Cubic | Bitmap/Bézier curves/Cubic | Using the data storage type defined on this page for raster images, and the draw_line function defined in this other one, draw a cubic bezier curve
(definition on Wikipedia).
| #Kotlin | Kotlin | // Version 1.2.40
import java.awt.Color
import java.awt.Graphics
import java.awt.image.BufferedImage
import kotlin.math.abs
import java.io.File
import javax.imageio.ImageIO
class Point(var x: Int, var y: Int)
class BasicBitmapStorage(width: Int, height: Int) {
val image = BufferedImage(width, height, Buffered... | Give a code snippet in #Kotlin
Using the data storage type defined on this page for raster images, and the draw_line function defined in this other one, draw a cubic bezier curve
(definition on Wikipedia).
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Huffman_coding | Huffman coding | Huffman encoding is a way to assign binary codes to symbols that reduces the overall number of bits used to encode a typical string of those symbols.
For example, if you use letters as symbols and have details of the frequency of occurrence of those letters in typical strings, then you could just encode each letter wi... | #Racket | Racket |
#lang racket
(require data/heap
data/bit-vector)
;; A node is either an interior, or a leaf.
;; In either case, they record an item with an associated frequency.
(struct node (freq) #:transparent)
(struct interior node (left right) #:transparent)
(struct leaf node (val) #:transparent)
;; node<=?: node ... | Give a code snippet in #Racket
Huffman encoding is a way to assign binary codes to symbols that reduces the overall number of bits used to encode a typical string of those symbols.
For example, if you use letters as symbols and have details of the frequency of occurrence of those letters in typical strings, then you ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #Julia | Julia | using Primes, Formatting
function chowla(n)
if n < 1
throw("Chowla function argument must be positive")
elseif n < 4
return zero(n)
else
f = [one(n)]
for (p,e) in factor(n)
f = reduce(vcat, [f*p^j for j in 1:e], init=f)
end
return sum(f) - one(n)... | Give a code snippet in #Julia
Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n ... | 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... | #Pascal | Pascal |
program sleepBeau;
uses
sysutils; //Format
const
iterations = 1000*1000;
fmt = 'Wakings over %d repetitions = %d'+#13#10+
'Percentage probability of heads on waking = %8.5f%%';
var
i,
heads,
wakings,
flip: Uint32;
begin
randomize;
for i :=1 to iterations do
Begin
flip := random(2)+1;//--... | Give a code snippet in #Pascal
Background on the task
In decision theory, The Sleeping Beauty Problem
is a problem invented by Arnold Zoboff and first publicized on Usenet. The experimental
subject, named Sleeping Beauty, agrees to an experiment as follows:
Sleeping Beauty volunteers to be put into a deep sleep on a S... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Gnome_sort | Sorting algorithms/Gnome sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #AutoHotkey | AutoHotkey | MsgBox % GnomeSort("")
MsgBox % GnomeSort("xxx")
MsgBox % GnomeSort("3,2,1")
MsgBox % GnomeSort("dog,000000,xx,cat,pile,abcde,1,cat,zz,xx,z")
GnomeSort(var) { ; SORT COMMA SEPARATED LIST
StringSplit a, var, `, ; make array, size = a0
i := 2, j := 3
While i <= a0 { ... | Give a code snippet in #AutoHotkey
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 |
Qui... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Deming%27s_Funnel | Deming's Funnel | W Edwards Deming was an American statistician and management guru who used physical demonstrations to illuminate his teachings. In one demonstration Deming repeatedly dropped marbles through a funnel at a target, marking where they landed, and observing the resulting pattern. He applied a sequence of "rules" to try to ... | #J | J |
dx=:".0 :0-.LF
_0.533 0.270 0.859 _0.043 _0.205 _0.127 _0.071 0.275
1.251 _0.231 _0.401 0.269 0.491 0.951 1.150 0.001
_0.382 0.161 0.915 2.080 _2.337 0.034 _0.126 0.014
0.709 0.129 _1.093 _0.483 _1.193 0.020 _0.051 0.047
_0.095 0.695 0.340 _0.182 0.287 0.213 _0.423 _0.021
_0.134 1.798 0.021 _1.099 _0.361 1.636 ... | Give a code snippet in #J
W Edwards Deming was an American statistician and management guru who used physical demonstrations to illuminate his teachings. In one demonstration Deming repeatedly dropped marbles through a funnel at a target, marking where they landed, and observing the resulting pattern. He applied a seq... | 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)
| #Scheme | Scheme | (define (leap-year? n)
(apply (lambda (a b c) (or a (and (not b) c)))
(map (lambda (m) (zero? (remainder n m)))
'(400 100 4)))) | Give a code snippet in #Scheme
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/Taxicab_numbers | Taxicab numbers |
A taxicab number (the definition that is being used here) is a positive integer that can be expressed as the sum of two positive cubes in more than one way.
The first taxicab number is 1729, which is:
13 + 123 and also
93 + 103.
Taxicab numbers are also known as:
taxi numbers
tax... | #zkl | zkl | fcn taxiCabNumbers{
const HeapSZ=0d5_000_000;
iCubes:=[1..120].apply("pow",3);
sum2cubes:=Data(HeapSZ).fill(0); // BFheap of 1 byte zeros
taxiNums:=List();
foreach i,i3 in ([1..].zip(iCubes)){
foreach j,j3 in ([i+1..].zip(iCubes[i,*])){
ij3:=i3+j3;
if(z:=sum2cubes[ij3]){
taxiNums.... | Give a code snippet in #zkl
A taxicab number (the definition that is being used here) is a positive integer that can be expressed as the sum of two positive cubes in more than one way.
The first taxicab number is 1729, which is:
13 + 123 and also
93 + 103.
Taxicab numbers are also know... | 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 ... | #Draco | Draco | *char q=
"proc main() void:\r\n"
" [128]char l;\r\n"
" char ch;\r\n"
" channel input text qc, lc;\r\n"
" open(qc, q);\r\n"
" writeln(\"*char q=\");\r\n"
" while readln(qc; &l[0]) do\r\n"
" write('\"');\r\n"
" open(lc, &l[0]);\r\n"
" while read(lc; ch) do\r\n"
" if ch='\... | Give a code snippet in #Draco
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/Literals/Integer | Literals/Integer | Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be interpreted by the compiler or... | #M4 | M4 | eval(10) # base 10
eval(010) # base 8
eval(0x10) # base 16 | Give a code snippet in #M4
Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be in... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Interactive_programming_(repl) | Interactive programming (repl) | Many language implementations come with an interactive mode.
This is a command-line interpreter that reads lines from the user and evaluates these lines as statements or expressions.
An interactive mode may also be known as a command mode, a read-eval-print loop (REPL), or a shell.
Task
Show how to start this... | #Octave | Octave | $ octave
GNU Octave, version 3.0.2
Copyright (C) 2008 John W. Eaton and others.
This is free software; see the source code for copying conditions.
There is ABSOLUTELY NO WARRANTY; not even for MERCHANTIBILITY or
FITNESS FOR A PARTICULAR PURPOSE. For details, type `warranty'.
Octave was configured for "i586-mandriva-... | Give a code snippet in #Octave
Many language implementations come with an interactive mode.
This is a command-line interpreter that reads lines from the user and evaluates these lines as statements or expressions.
An interactive mode may also be known as a command mode, a read-eval-print loop (REPL), or a shell.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_length | Array length | Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I befo... | #Fortran | Fortran |
MODULE EXAMPLE
CONTAINS
SUBROUTINE ABOUND(A)
CHARACTER*(*) A(:) !One dimensional array, unspecified bounds.
WRITE (6,*) "Lower bound",LBOUND(A),", Upper bound",UBOUND(A)
WRITE (6,*) "Element size",LEN(A(LBOUND(A)))
WRITE (6,*) A
END SUBROUTINE ABOUND... | Give a code snippet in #Fortran
Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter fre... | 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
... | #Lingo | Lingo | on isPrime (n)
if n<=1 or (n>2 and n mod 2=0) then return FALSE
sq = sqrt(n)
repeat with i = 3 to sq
if n mod i = 0 then return FALSE
end repeat
return TRUE
end | Give a code snippet in #Lingo
Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other loops... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Infinite | Loops/Infinite | Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within l... | #ActionScript | ActionScript | while (true) {
trace("SPAM");
} | Give a code snippet in #ActionScript
Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Palindrome_detection | Palindrome detection | A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as a wrapper to the first) which ... | #BCPL | BCPL | get "libhdr"
let palindrome(s) = valof
$( let l = s%0
for i = 1 to l/2
unless s%i = s%(l+1-i)
resultis false
resultis true
$)
let inexact(s) = valof
$( let temp = vec 1+256/BYTESPERWORD
temp%0 := 0
for i = 1 to s%0 do
$( let ch = s%i | 32
if '0'<=ch & ch<='9' | 'a... | Give a code snippet in #BCPL
A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #Maxima | Maxima | /* Function horner already exists in Maxima, though it operates on expressions, not lists of coefficients */
horner(5*x^3+2*x+1);
x*(5*x^2+2)+1
/* Here is an implementation */
horner2(p, x) := block([n, y, i],
n: length(p),
y: p[n],
for i: n - 1 step -1 thru 1 do y: y*x + p[i],
y
)$
horner2([-19, 7, -4,... | Give a code snippet in #Maxima
A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Seed7 | Seed7 | $ include "seed7_05.s7i";
include "draw.s7i";
include "color.s7i";
const proc: writePPM (in string: fileName, in PRIMITIVE_WINDOW: aWindow) is func
local
var file: ppmFile is STD_NULL;
var integer: x is 0;
var integer: y is 0;
var color: pixColor is black;
begin
ppmFile := open(fileName, "... | Give a code snippet in #Seed7
Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Merge_sort | Sorting algorithms/Merge sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Mercury | Mercury |
:- module merge_sort.
:- interface.
:- import_module list.
:- type split_error ---> split_error.
:- func merge_sort(list(T)) = list(T).
:- pred merge_sort(list(T)::in, list(T)::out) is det.
:- implementation.
:- import_module int, exception.
merge_sort(U) = S :- merge_sort(U, S).
merge_sort(U, S) :- m... | Give a code snippet in #Mercury
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Runtime_evaluation | Runtime evaluation | Task
Demonstrate a language's ability for programs to execute code written in the language provided at runtime.
Show what kind of program fragments are permitted (e.g. expressions vs. statements), and how to get values in and out (e.g. environments, arguments, return values), if applicable what lexical/static environ... | #Julia | Julia | include("myfile.jl") | Give a code snippet in #Julia
Task
Demonstrate a language's ability for programs to execute code written in the language provided at runtime.
Show what kind of program fragments are permitted (e.g. expressions vs. statements), and how to get values in and out (e.g. environments, arguments, return values), if applica... | 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.)
| #Gri | Gri | # this is a comment
show 123 # this too is a comment | Give a code snippet in #Gri
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/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a st... | #C.2B.2B | C++ | #include <string>
#include <boost/regex.hpp>
#include <iostream>
std::string csvToHTML( const std::string & ) ;
int main( ) {
std::string text = "Character,Speech\n"
"The multitude,The messiah! Show us the messiah!\n"
"Brians mother,<angry>Now you listen here! He's not the me... | Give a code snippet in #C.2B.2B
Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Thue-Morse | Thue-Morse | Task
Create a Thue-Morse sequence.
See also
YouTube entry: The Fairest Sharing Sequence Ever
YouTube entry: Math and OCD - My story with the Thue-Morse sequence
Task: Fairshare between two and more
| #D | D | import std.range;
import std.stdio;
struct TM {
private char[] sequence = ['0'];
private char[] inverse = ['1'];
private char[] buffer;
enum empty = false;
auto front() {
return sequence;
}
auto popFront() {
buffer = sequence;
sequence ~= inverse;
inve... | Give a code snippet in #D
Task
Create a Thue-Morse sequence.
See also
YouTube entry: The Fairest Sharing Sequence Ever
YouTube entry: Math and OCD - My story with the Thue-Morse sequence
Task: Fairshare between two and more
| 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... | #MINIL | MINIL | // Number of combinations nCr
00 0E Go: ENT R0 // n
01 1E ENT R1 // r
02 2C CLR R2
03 2A Loop: ADD1 R2
04 0D DEC R0
05 1D DEC R1
06 C3 JNZ Loop
07 3C CLR R3 // for result
08 3A ADD1 R3
09 0A Next: ADD1 R0
0A 1A ADD1 R1
0B 50 R5... | Give a code snippet in #MINIL
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
−
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Cursor_positioning | Terminal control/Cursor positioning |
Task
Move the cursor to column 3, row 6, and display the word "Hello" (without the quotes), so that the letter H is in column 3 on row 6.
| #C.23 | C# | static void Main(string[] args)
{
Console.SetCursorPosition(3, 6);
Console.Write("Hello");
} | Give a code snippet in #C.23
Task
Move the cursor to column 3, row 6, and display the word "Hello" (without the quotes), so that the letter H is in column 3 on row 6.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to... | #C.2B.2B | C++ | #include <string>
#include <iostream>
#include <algorithm>
#include <cctype>
class MyTransform {
private :
int shift ;
public :
MyTransform( int s ) : shift( s ) { }
char operator( )( char c ) {
if ( isspace( c ) )
return ' ' ;
else {
static std::string letters( "abcdefghijklmnopqrstuvwxy... | Give a code snippet in #C.2B.2B
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_concatenation | Array concatenation | Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| #C | C | #include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define ARRAY_CONCAT(TYPE, A, An, B, Bn) \
(TYPE *)array_concat((const void *)(A), (An), (const void *)(B), (Bn), sizeof(TYPE));
void *array_concat(const void *a, size_t an,
const void *b, size_t bn, size_t s)
{
char *p = malloc(s * (... | Give a code snippet in #C
Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Almost_prime | Almost prime | A k-Almost-prime is a natural number
n
{\displaystyle n}
that is the product of
k
{\displaystyle k}
(possibly identical) primes.
Example
1-almost-primes, where
k
=
1
{\displaystyle k=1}
, are the prime numbers themselves.
2-almost-primes, where
k
=
2
{\displaystyl... | #Swift | Swift | struct KPrimeGen: Sequence, IteratorProtocol {
let k: Int
private(set) var n: Int
private func isKPrime() -> Bool {
var primes = 0
var f = 2
var rem = n
while primes < k && rem > 1 {
while rem % f == 0 && rem > 1 {
rem /= f
primes += 1
}
f += 1
}
r... | Give a code snippet in #Swift
A k-Almost-prime is a natural number
n
{\displaystyle n}
that is the product of
k
{\displaystyle k}
(possibly identical) primes.
Example
1-almost-primes, where
k
=
1
{\displaystyle k=1}
, are the prime numbers themselves.
2-almost-primes, wh... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat... | #C | C | #include <stdio.h>
#include <stdlib.h>
/* func: our one and only data type; it holds either a pointer to
a function call, or an integer. Also carry a func pointer to
a potential parameter, to simulate closure */
typedef struct func_t *func;
typedef struct func_t {
func (*fn) (func, fu... | Give a code snippet in #C
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variab... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Delete_a_file | Delete a file | Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Python | Python | import os
# current directory
os.remove("output.txt")
os.rmdir("docs")
# root directory
os.remove("/output.txt")
os.rmdir("/docs") | Give a code snippet in #Python
Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Fortran | Fortran |
INTEGER ENUFF !A value has to be specified beforehand,.
PARAMETER (ENUFF = 2468) !Provide some provenance.
CHARACTER*(ENUFF) ALINE !A perfect size?
CHARACTER*66 FNAME !What about file name sizes?
INTEGER LINPR,IN !I/O unit numbers.
INTEGER L,N !A length, and a record counter.
... | Give a code snippet in #Fortran
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/One-dimensional_cellular_automata | One-dimensional cellular automata | Assume an array of cells with an initial distribution of live and dead cells,
and imaginary cells off the end of the array having fixed values.
Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation.
If, in the follow... | #BBC_BASIC | BBC BASIC | DIM rule$(7)
rule$() = "0", "0", "0", "1", "0", "1", "1", "0"
now$ = "01110110101010100100"
FOR generation% = 0 TO 9
PRINT "Generation " ; generation% ":", now$
next$ = ""
FOR cell% = 1 TO LEN(now$)
next$ += rule$(EVAL("%"+MID$("0"+now$+"0", cell%, 3)))
... | Give a code snippet in #BBC_BASIC
Assume an array of cells with an initial distribution of live and dead cells,
and imaginary cells off the end of the array having fixed values.
Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the cur... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Heapsort | Sorting algorithms/Heapsort |
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
... | #LotusScript | LotusScript |
Public Sub heapsort(pavIn As Variant)
Dim liCount As Integer, liEnd As Integer
Dim lvTemp As Variant
liCount = UBound(pavIn) + 1
heapify pavIn, liCount
liEnd = liCount - 1
While liEnd > 0
lvTemp = pavIn(liEnd)
pavIn(liEnd) = pavIn(0)
pavIn(0) = lvTemp
liEnd = liEnd -1
siftDown pa... | Give a code snippet in #LotusScript
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/Multisplit | Multisplit | It is often necessary to split a string into pieces
based on several different (potentially multi-character) separator strings,
while still retaining the information about which separators were present in the input.
This is particularly useful when doing small parsing tasks.
The task is to write code to demonstrate ... | #F.23 | F# | > "a!===b=!=c".Split([|"=="; "!="; "="|], System.StringSplitOptions.None);;
val it : string [] = [|"a"; ""; "b"; ""; "c"|]
> "a!===b=!=c".Split([|"="; "!="; "=="|], System.StringSplitOptions.None);;
val it : string [] = [|"a"; ""; ""; "b"; ""; "c"|] | Give a code snippet in #F.23
It is often necessary to split a string into pieces
based on several different (potentially multi-character) separator strings,
while still retaining the information about which separators were present in the input.
This is particularly useful when doing small parsing tasks.
The task is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Haversine_formula | Haversine formula |
This page uses content from Wikipedia. The original article was at Haversine formula. 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)
The haversine formula is an equation important in navigation, g... | #Transact-SQL | Transact-SQL | CREATE FUNCTION [dbo].[Haversine](@Lat1 AS DECIMAL(9,7), @Lon1 AS DECIMAL(10,7), @Lat2 AS DECIMAL(9,7), @Lon2 AS DECIMAL(10,7))
RETURNS DECIMAL(12,7)
AS
BEGIN
DECLARE @R DECIMAL(11,7);
DECLARE @dLat DECIMAL(9,7);
DECLARE @dLon DECIMAL(10,7);
DECLARE @a DECIMAL(10,7);
DECLARE @c DECIMAL(10,7);
SET @R = 6372.8;
... | Give a code snippet in #Transact-SQL
This page uses content from Wikipedia. The original article was at Haversine formula. 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)
The haversine formula is ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Higher-order_functions | Higher-order functions | Task
Pass a function as an argument to another function.
Related task
First-class functions
| #Ring | Ring |
# Project : Higher-order functions
docalcs(1,10,"squares",:square)
docalcs(1,10,"cubes",:cube)
func square(n)
return n * n
func cube(n)
return n * n * n
func docalcs(from2,upto,title,func2)
see title + " -> " + nl
for i = from2 to upto
x = call func2(i)
... | Give a code snippet in #Ring
Task
Pass a function as an argument to another function.
Related task
First-class functions
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_duplicate_files | Find duplicate files | In a large directory structure it is easy to inadvertently leave unnecessary copies of files around, which can use considerable disk space and create confusion.
Task
Create a program which, given a minimum size and a folder/directory, will find all files of at least size bytes with duplicate contents under the dire... | #Objeck | Objeck | use System.IO.File;
use System.Time;
use Collection;
class Duplicate {
function : Main(args : String[]) ~ Nil {
if(args->Size() = 2) {
file_sets := SortDups(GetDups(args[0], args[1]->ToInt()));
each(i : file_sets) {
file_set := file_sets->Get(i)->As(Vector);
if(file_set->Size() > 1) ... | Give a code snippet in #Objeck
In a large directory structure it is easy to inadvertently leave unnecessary copies of files around, which can use considerable disk space and create confusion.
Task
Create a program which, given a minimum size and a folder/directory, will find all files of at least size bytes with d... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dijkstra%27s_algorithm | Dijkstra's algorithm | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Dijkstra's algorithm, conceived by Dutch computer scientist Edsger Dijkstra in 1956 and published in 1959, is a graph search algorithm that solves the single-source shortest path pro... | #Swift | Swift | typealias WeightedEdge = (Int, Int, Int)
struct Grid<T> {
var nodes: [Node<T>]
mutating func addNode(data: T) -> Int {
nodes.append(Node(data: data, edges: []))
return nodes.count - 1
}
mutating func createEdges(weights: [WeightedEdge]) {
for (start, end, weight) in weights {
nodes[sta... | Give a code snippet in #Swift
This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Dijkstra's algorithm, conceived by Dutch computer scientist Edsger Dijkstra in 1956 and published in 1959, is a graph search algorithm that solves the ... | 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... | #Ring | Ring |
Load "guilib.ring"
new qapp {
q1=NULL q2=NULL
win1 = new qwidget() {
setwindowtitle("play sound!") show()
setgeometry(100,100,400,400)
}
new qpushbutton(win1) {
setgeometry(50,50,100,30)
settext("play1")
setcli... | Give a code snippet in #Ring
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 o... | 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 ... | #C | C |
#include<graphics.h>
#include<stdlib.h>
#include<stdio.h>
#include<time.h>
typedef struct{
double x,y;
}point;
void pythagorasTree(point a,point b,int times){
point c,d,e;
c.x = b.x - (a.y - b.y);
c.y = b.y - (b.x - a.x);
d.x = a.x - (a.y - b.y);
d.y = a.y - (b.x - a.x);
e.x = d.x + ( b.x - a.x ... | Give a code snippet in #C
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 on... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Show_the_epoch | Show the epoch | Task
Choose popular date libraries used by your language and show the epoch those libraries use.
A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the scenes by the implementers), b... | #TUSCRIPT | TUSCRIPT | $$ MODE TUSCRIPT
- epoch
number=1
dayofweeknr=DATE (date,day,month,year,number)
epoch=JOIN(year,"-",month,day)
PRINT "epoch: ", epoch," (daynumber ",number,")"
- today's daynumber
dayofweeknr=DATE (today,day,month,year,number)
date=JOIN (year,"-",month,day)
PRINT "today's date: ", date," (daynumber ", number,")" | Give a code snippet in #TUSCRIPT
Task
Choose popular date libraries used by your language and show the epoch those libraries use.
A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Patience_sort | Sorting algorithms/Patience sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Nim | Nim | import std/decls
func patienceSort[T](a: var openArray[T]) =
if a.len < 2: return
var piles: seq[seq[T]]
for elem in a:
block processElem:
for pile in piles.mitems:
if pile[^1] > elem:
pile.add(elem)
break processElem
piles.add(@[elem])
for i in 0..a.high:
... | Give a code snippet in #Nim
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed ... | #ALGOL_60 | ALGOL 60 | begin
comment Create a two-dimensional array at runtime - Algol 60;
integer n,m;
ininteger(0,m);
ininteger(0,n);
begin
integer array a[1:m,1:n];
a[m,n] := 99;
outinteger(1,a[m,n]);
outstring(1,"\n")
end;
comment array a : out of scope;
end | Give a code snippet in #ALGOL_60
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those n... | 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,... | #Perl | Perl | use strict;
use warnings;
use Fcntl qw( :flock SEEK_END );
use constant {
RECORD_FIELDS => [qw( account password UID GID GECOS directory shell )],
GECOS_FIELDS => [qw( fullname office extension homephone email )],
RECORD_SEP => ':',
GECOS_SEP => ',',
PASSWD_FILE => 'passwd.txt',
};
#... | Give a code snippet in #Perl
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 us... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Random_Latin_squares | Random Latin squares | A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1
2 1 0 3
3 0 1 2
1 3 2 0
Task... | #zkl | zkl | fcn randomLatinSquare(n,symbols=[1..]){ //--> list of lists
if(n<=0) return(T);
square,syms := List(), symbols.walker().walk(n);
do(n){ syms=syms.copy(); square.append(syms.append(syms.pop(0))) }
// shuffle rows, transpose & shuffle columns
T.zip(square.shuffle().xplode()).shuffle();
}
fcn rls2String(sq... | Give a code snippet in #zkl
A Latin square of size n is an arrangement of n symbols in an n-by-n square in such a way that each row and column has each symbol appearing exactly once.
A randomised Latin square generates random configurations of the symbols for any given n.
Example n=4 randomised Latin square
0 2 3 1... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Axiom | Axiom | )abbrev package TESTP TestPackage
TestPackage() : with
test: () -> List((()->Integer))
== add
test() == [(() +-> i^2) for i in 1..10] | Give a code snippet in #Axiom
Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_duplicate_files | Find duplicate files | In a large directory structure it is easy to inadvertently leave unnecessary copies of files around, which can use considerable disk space and create confusion.
Task
Create a program which, given a minimum size and a folder/directory, will find all files of at least size bytes with duplicate contents under the dire... | #Nim | Nim | import algorithm
import os
import strformat
import strutils
import tables
import std/sha1
import times
type
# Mapping "size" -> "list of paths".
PathsFromSizes = Table[BiggestInt, seq[string]]
# Mapping "hash" -> "list fo paths".
PathsFromHashes = Table[string, seq[string]]
# Information data.
Info ... | Give a code snippet in #Nim
In a large directory structure it is easy to inadvertently leave unnecessary copies of files around, which can use considerable disk space and create confusion.
Task
Create a program which, given a minimum size and a folder/directory, will find all files of at least size bytes with dupl... | 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 ... | #R | R | distcheck <- function(fn, repetitions=1e4, delta=3)
{
if(is.character(fn))
{
fn <- get(fn)
}
if(!is.function(fn))
{
stop("fn is not a function")
}
samp <- fn(n=repetitions)
counts <- table(samp)
expected <- repetitions/length(counts)
lbound <- expected * (1 - 0.01*delta)
... | Give a code snippet in #R
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 inte... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_a_set_of_characters_from_a_string | Strip a set of characters from a string | Task
Create a function that strips a set of characters from a string.
The function should take two arguments:
a string to be stripped
a string containing the set of characters to be stripped
The returned string should contain the first string, stripped of any characters in the second argument:
print str... | #Python | Python | >>> def stripchars(s, chars):
... return s.translate(None, chars)
...
>>> stripchars("She was a soul stripper. She took my heart!", "aei")
'Sh ws soul strppr. Sh took my hrt!' | Give a code snippet in #Python
Task
Create a function that strips a set of characters from a string.
The function should take two arguments:
a string to be stripped
a string containing the set of characters to be stripped
The returned string should contain the first string, stripped of any characters in ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Zeckendorf_arithmetic | Zeckendorf arithmetic | This task is a total immersion zeckendorf task; using decimal numbers will attract serious disapprobation.
The task is to implement addition, subtraction, multiplication, and division using Zeckendorf number representation. Optionally provide decrement, increment and comparitive operation functions.
Addition
Like bin... | #PicoLisp | PicoLisp | (seed (in "/dev/urandom" (rd 8)))
(de unpad (Lst)
(while (=0 (car Lst))
(pop 'Lst) )
Lst )
(de numz (N)
(let Fibs (1 1)
(while (>= N (+ (car Fibs) (cadr Fibs)))
(push 'Fibs (+ (car Fibs) (cadr Fibs))) )
(make
(for I (uniq Fibs)
(if (> I N)
(lin... | Give a code snippet in #PicoLisp
This task is a total immersion zeckendorf task; using decimal numbers will attract serious disapprobation.
The task is to implement addition, subtraction, multiplication, and division using Zeckendorf number representation. Optionally provide decrement, increment and comparitive opera... | christopher/rosetta-code | |
http://rosettacode.org/wiki/UTF-8_encode_and_decode | UTF-8 encode and decode | As described in UTF-8 and in Wikipedia, UTF-8 is a popular encoding of (multi-byte) Unicode code-points into eight-bit octets.
The goal of this task is to write a encoder that takes a unicode code-point (an integer representing a unicode character) and returns a sequence of 1-4 bytes representing that character in the... | #BaCon | BaCon | DECLARE x TYPE STRING
CONST letter$ = "A ö Ж € 𝄞"
PRINT "Char", TAB$(1), "Unicode", TAB$(2), "UTF-8 (hex)"
PRINT "-----------------------------------"
FOR x IN letter$
PRINT x, TAB$(1), "U+", HEX$(UCS(x)), TAB$(2), COIL$(LEN(x), HEX$(x[_-1] & 255))
NEXT | Give a code snippet in #BaCon
As described in UTF-8 and in Wikipedia, UTF-8 is a popular encoding of (multi-byte) Unicode code-points into eight-bit octets.
The goal of this task is to write a encoder that takes a unicode code-point (an integer representing a unicode character) and returns a sequence of 1-4 bytes rep... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Special_variables | Special variables | Special variables have a predefined meaning within a computer programming language.
Task
List the special variables used within the language.
| #Quackery | Quackery | $foo scalar (object)
@foo ordered array
%foo unordered hash (associative array)
&foo code/rule/token/regex
::foo package/module/class/role/subset/enum/type/grammar | Give a code snippet in #Quackery
Special variables have a predefined meaning within a computer programming language.
Task
List the special variables used within the language.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sequence_of_non-squares | Sequence of non-squares | Task
Show that the following remarkable formula gives the sequence of non-square natural numbers:
n + floor(1/2 + sqrt(n))
Print out the values for n in the range 1 to 22
Show that no squares occur for n less than one million
This is sequence A000037 in the OEIS database.
| #GAP | GAP | # Here we use generators : the given formula doesn't need one, but the alternate
# non-squares function is better done with a generator.
# The formula is implemented with exact floor(sqrt(n)), so we use
# a trick: multiply by 100 to get the first decimal digit of the
# square root of n, then add 5 (that's 1/2 multipl... | Give a code snippet in #GAP
Task
Show that the following remarkable formula gives the sequence of non-square natural numbers:
n + floor(1/2 + sqrt(n))
Print out the values for n in the range 1 to 22
Show that no squares occur for n less than one million
This is sequence A000037 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Foreach | Loops/Foreach | Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for... | #11l | 11l | V things = [‘Apple’, ‘Banana’, ‘Coconut’]
L(thing) things
print(thing) | Give a code snippet in #11l
Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/D... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Delphi | Delphi |
procedure ReadFileByLine;
var
TextFile: text;
TextLine: String;
begin
Assign(TextFile, 'c:\test.txt');
Reset(TextFile);
while not Eof(TextFile) do
Readln(TextFile, TextLine);
CloseFile(TextFile);
end;
| Give a code snippet in #Delphi
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program strEmpty.s */
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/* Initialized data */
.data
szNotEmptyString: .asciz "String is not empty. \n"
szEmptyString: .asciz "String is e... | Give a code snippet in #ARM_Assembly
Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.... | 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 ... | #R | R | x <- 0
if(x == 0) print("foo")
x <- 1
if(x == 0) print("foo")
if(x == 0) print("foo") else print("bar") | Give a code snippet in #R
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 cond... | christopher/rosetta-code | |
http://rosettacode.org/wiki/AVL_tree | AVL tree |
This page uses content from Wikipedia. The original article was at AVL tree. 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 computer science, an AVL tree is a self-balancing binary search tree.... | #D | D | import std.stdio, std.algorithm;
class AVLtree {
private Node* root;
private static struct Node {
private int key, balance;
private Node* left, right, parent;
this(in int k, Node* p) pure nothrow @safe @nogc {
key = k;
parent = p;
}
}
publi... | Give a code snippet in #D
This page uses content from Wikipedia. The original article was at AVL tree. 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 computer science, an AVL tree is a self-ba... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #Clay | Clay |
import printer.formatter as pf;
euler(f, y, a, b, h) {
while (a < b) {
println(pf.rightAligned(2, a), " ", y);
a += h;
y += h * f(y);
}
}
main() {
for (i in [2.0, 5.0, 10.0]) {
println("\nFor delta = ", i, ":");
euler((temp) => -0.07 * (temp - 20), 100.0, 0.0, 1... | Give a code snippet in #Clay
Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/List_rooted_trees | List rooted trees | You came back from grocery shopping. After putting away all the goods, you are left with a pile of plastic bags, which you want to save for later use, so you take one bag and stuff all the others into it, and throw it under the sink. In doing so, you realize that there are various ways of nesting the bags, with all... | #Ring | Ring |
# Project : List rooted trees
list = "()"
addstr = []
flag = 0
newstr = []
str = []
np = [1,2,3,4]
for nr = 1 to len(np)
if nr = 1
bg1 = "bag"
else
bg1 = "bags"
ok
see "for " + nr + " " + bg1 + " :" + nl
permutation(list,nr*2)
listroot(nr*2)
next
see "ok" + nl
... | Give a code snippet in #Ring
You came back from grocery shopping. After putting away all the goods, you are left with a pile of plastic bags, which you want to save for later use, so you take one bag and stuff all the others into it, and throw it under the sink. In doing so, you realize that there are various ways... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Non-decimal_radices/Convert | Non-decimal radices/Convert | Number base conversion is when you express a stored integer in an integer base, such as in octal (base 8) or binary (base 2). It also is involved when you take a string representing a number in a given base and convert it to the stored integer form. Normally, a stored integer is in binary, but that's typically invisibl... | #Kotlin | Kotlin | // version 1.0.6
fun min(x: Int, y: Int) = if (x < y) x else y
fun convertToBase(n: Int, b: Int): String {
if (n < 2 || b < 2 || b == 10 || b > 36) return n.toString() // leave as decimal
val sb = StringBuilder()
var digit: Int
var nn = n
while (nn > 0) {
digit = nn % b
if (digit... | Give a code snippet in #Kotlin
Number base conversion is when you express a stored integer in an integer base, such as in octal (base 8) or binary (base 2). It also is involved when you take a string representing a number in a given base and convert it to the stored integer form. Normally, a stored integer is in binar... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multiple_distinct_objects | Multiple distinct objects | Create a sequence (array, list, whatever) consisting of n distinct, initialized items of the same type. n should be determined at runtime.
By distinct we mean that if they are mutable, changes to one do not affect all others; if there is an appropriate equality operator they are considered unequal; etc. The code need ... | #Forth | Forth | include FMS-SI.f
include FMS-SILib.f
\ create a list of VAR objects the right way
\ each: returns a unique object reference
o{ 0 0 0 } dup p: o{ 0 0 0 }
dup each: drop . 10774016
dup each: drop . 10786896
dup each: drop . 10786912
\ create a list of VAR objects the wrong way
\ each: returns the same obje... | Give a code snippet in #Forth
Create a sequence (array, list, whatever) consisting of n distinct, initialized items of the same type. n should be determined at runtime.
By distinct we mean that if they are mutable, changes to one do not affect all others; if there is an appropriate equality operator they are consider... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet | Generate lower case ASCII alphabet | Task
Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence.
For this basic task use a reliable style of coding, a sty... | #Rust | Rust | fn main() {
// An iterator over the lowercase alpha's
let ascii_iter = (0..26)
.map(|x| (x + b'a') as char);
println!("{:?}", ascii_iter.collect::<Vec<char>>());
} | Give a code snippet in #Rust
Task
Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence.
For this basic task use a r... | christopher/rosetta-code |
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