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http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#Clojure
Clojure
  (defn squeeze [s c] (let [spans (partition-by #(= c %) s) span-out (fn [span] (if (= c (first span)) (str c) (apply str span)))] (apply str (map span-out spans))))   (defn test-squeeze [s c] (let [out (squeeze s c)] (println (format "Inp...
http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#Cowgol
Cowgol
include "cowgol.coh"; include "strings.coh";   sub squeeze(ch: uint8, str: [uint8], buf: [uint8]): (r: [uint8]) is r := buf; var prev: uint8 := 0; while [str] != 0 loop if prev != ch or [str] != ch then prev := [str]; [buf] := prev; buf := @next buf; end i...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#Arturo
Arturo
descending: @[ loop 1..9 'a [ loop 1..dec a 'b [ loop 1..dec b 'c [ loop 1..dec c 'd [ loop 1..dec d 'e [ loop 1..dec e 'f [ loop 1..dec f 'g [ loop 1..dec g 'h [ ...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#AWK
AWK
  # syntax: GAWK -f DESCENDING_PRIMES.AWK BEGIN { start = 1 stop = 99999999 for (i=start; i<=stop; i++) { leng = length(i) flag = 1 for (j=1; j<leng; j++) { if (substr(i,j,1) <= substr(i,j+1,1)) { flag = 0 break } } if (flag) { if (is...
http://rosettacode.org/wiki/Determine_if_two_triangles_overlap
Determine if two triangles overlap
Determining if two triangles in the same plane overlap is an important topic in collision detection. Task Determine which of these pairs of triangles overlap in 2D:   (0,0),(5,0),(0,5)     and   (0,0),(5,0),(0,6)   (0,0),(0,5),(5,0)     and   (0,0),(0,5),(5,0)   (0,0),(5,0),(0,5)     and   (-10,0),(-5,0),(-1,6)...
#AutoHotkey
AutoHotkey
TrianglesIntersect(T1, T2){ ; T1 := [[x1,y1],[x2,y2],[x3,y3]] , T2 :=[[x4,y4],[x5,y5],[x6,y6]] counter := 0 for i, Pt in T1 counter += PointInTriangle(Pt, T2) ; check if any coordinate of triangle 1 is inside triangle 2 for i, Pt in T2 counter += PointInTriangle(Pt, T1) ; check if any coordinate of triangle 2 ...
http://rosettacode.org/wiki/Determinant_and_permanent
Determinant and permanent
For a given matrix, return the determinant and the permanent of the matrix. The determinant is given by det ( A ) = ∑ σ sgn ⁡ ( σ ) ∏ i = 1 n M i , σ i {\displaystyle \det(A)=\sum _{\sigma }\operatorname {sgn}(\sigma )\prod _{i=1}^{n}M_{i,\sigma _{i}}} while the permanent is given by ...
#C.2B.2B
C++
#include <iostream> #include <vector>   template <typename T> std::ostream &operator<<(std::ostream &os, const std::vector<T> &v) { auto it = v.cbegin(); auto end = v.cend();   os << '['; if (it != end) { os << *it; it = std::next(it); } while (it != end) { os << ", " << ...
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#ALGOL_68
ALGOL 68
PROC raise exception= ([]STRING args)VOID: ( put(stand error, ("Exception: ",args, newline)); stop );   PROC raise zero division error := VOID: raise exception("integer division or modulo by zero");   PROC int div = (INT a,b)REAL: a/b; PROC int over = (INT a,b)INT: a%b; PROC int mod = (INT a,b)INT: a%*b;   BE...
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#ALGOL_W
ALGOL W
begin    % determnines whether the string contains an integer, real or imaginary  %  % number. Returns true if it does, false otherwise  % logical procedure isNumeric( string(32) value text ) ; begin   logical ok;  % the "number" cannot be blank ...
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#Apex
Apex
  String numericString = '123456'; String partlyNumericString = '123DMS'; String decimalString = '123.456';   System.debug(numericString.isNumeric()); // this will be true System.debug(partlyNumericString.isNumeric()); // this will be false System.debug(decimalString.isNumeric()); // this will be false System.debug(dec...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_unique_characters
Determine if a string has all unique characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are unique   indicate if or which character is duplicated and where   display each string and its length   (as the strings are being ...
#Arturo
Arturo
strings: [ "", ".", "abcABC", "XYZ ZYX", "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ", "01234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ0X", "hétérogénéité", "🎆🎃🎇🎈", "😍😀🙌💃😍🙌", "🐠🐟🐡🦈🐬🐳🐋🐡" ]   loop strings 'str [ chars: split str prints ["\"" ++ str ++ "\"" ~"(size |size str|):"]   if? ch...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_unique_characters
Determine if a string has all unique characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are unique   indicate if or which character is duplicated and where   display each string and its length   (as the strings are being ...
#AutoHotkey
AutoHotkey
unique_characters(str){ arr := [], res := "" for i, v in StrSplit(str) arr[v] := arr[v] ? arr[v] "," i : i for i, v in Arr if InStr(v, ",") res .= v "|" i " @ " v "`tHex = " format("{1:X}", Asc(i)) "`n" Sort, res, N res := RegExReplace(res, "`am)^[\d,]+\|") res := StrSplit(res, "`n").1 return """" str """...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#C.23
C#
using System; using static System.Linq.Enumerable;   public class Program { static void Main() { string[] input = { "", "The better the 4-wheel drive, the further you'll be from help when ya get stuck!", "headmistressship", "\"If I were two-faced, would I ...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#C.2B.2B
C++
#include <string> #include <iostream> #include <algorithm>   template<typename char_type> std::basic_string<char_type> collapse(std::basic_string<char_type> str) { auto i = std::unique(str.begin(), str.end()); str.erase(i, str.end()); return str; }   void test(const std::string& str) { std::cout << "ori...
http://rosettacode.org/wiki/Dice_game_probabilities
Dice game probabilities
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six. They roll their dice and sum the totals of the faces. The player with the highest total wins (i...
#Ruby
Ruby
def roll_dice(n_dice, n_faces) return [[0,1]] if n_dice.zero? one = [1] * n_faces zero = [0] * (n_faces-1) (1...n_dice).inject(one){|ary,_| (zero + ary + zero).each_cons(n_faces).map{|a| a.inject(:+)} }.map.with_index(n_dice){|n,sum| [sum,n]} # sum: total of the faces end   def game(dice1, faces1, dice2...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_the_same_characters
Determine if a string has all the same characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are the same   indicate if or which character is different from the previous character   display each string and its length   (as the...
#C.23
C#
using System;   namespace AllSame { class Program { static void Analyze(string s) { Console.WriteLine("Examining [{0}] which has a length of {1}:", s, s.Length); if (s.Length > 1) { var b = s[0]; for (int i = 1; i < s.Length; i++) { ...
http://rosettacode.org/wiki/Dining_philosophers
Dining philosophers
The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. It is a modification of a problem posed by Edsger Dijkstra. Five philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eating spaghetti. They eat at a rou...
#J
J
". noun define -. CRLF NB. Fixed tacit simulation code...   simulate=. ''"_@:((<@:(1 -~ 1&({::)) 1} ])@:(([ 0 0&$@(1!:2&2)@:(((6j3 ": 9&({::)) , ': '"_) , ' starts waiting and thinking about hunger.' ,~ 8&({::) {:: 0&({::)))@ :(<@:(6&({::) , 8&({::)) 6} ])@:((<@:((0 (0 {:: ])`(<@:(1 {:: ]))`(2 {:: ])} ])@:(3 8 2&...
http://rosettacode.org/wiki/Discordian_date
Discordian date
Task Convert a given date from the   Gregorian calendar   to the   Discordian calendar.
#Icon_and_Unicon
Icon and Unicon
link printf   procedure main() Demo(2010,1,1) Demo(2010,7,22) Demo(2012,2,28) Demo(2012,2,29) Demo(2012,3,1) Demo(2010,1,5) Demo(2011,5,3) Demo(2012,2,28) Demo(2012,2,29) Demo(2012,3,1) Demo(2010,7,22) Demo(2012,12,22) end   procedure Demo(y,m,d) #: demo display printf("%i-%...
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...
#jq
jq
# (*) If using gojq, uncomment the following line: # def keys_unsorted: keys;   # remove the first occurrence of $x from the input array def rm($x): index($x) as $ix | if $ix then .[:$ix] + .[$ix+1:] else . end;   # Input: a Graph # Output: a (possibly empty) stream of the neighbors of $node # that are also in the...
http://rosettacode.org/wiki/Digital_root
Digital root
The digital root, X {\displaystyle X} , of a number, n {\displaystyle n} , is calculated: find X {\displaystyle X} as the sum of the digits of n {\displaystyle n} find a new X {\displaystyle X} by summing the digits of X {\displaystyle X} , repeating until X {\displ...
#Elena
Elena
import extensions; import system'routines; import system'collections;   extension op { get DigitalRoot() { int additivepersistence := 0; long num := self;   while (num > 9) { num := num.toPrintable().toArray().selectBy:(ch => ch.toInt() - 48).summarize(new LongIntege...
http://rosettacode.org/wiki/Digital_root
Digital root
The digital root, X {\displaystyle X} , of a number, n {\displaystyle n} , is calculated: find X {\displaystyle X} as the sum of the digits of n {\displaystyle n} find a new X {\displaystyle X} by summing the digits of X {\displaystyle X} , repeating until X {\displ...
#Elixir
Elixir
defmodule Digital do def root(n, base\\10), do: root(n, base, 0)   defp root(n, base, ap) when n < base, do: {n, ap} defp root(n, base, ap) do Integer.digits(n, base) |> Enum.sum |> root(base, ap+1) end end   data = [627615, 39390, 588225, 393900588225] Enum.each(data, fn n -> {dr, ap} = Digital.root(n) ...
http://rosettacode.org/wiki/Digital_root/Multiplicative_digital_root
Digital root/Multiplicative digital root
The multiplicative digital root (MDR) and multiplicative persistence (MP) of a number, n {\displaystyle n} , is calculated rather like the Digital root except digits are multiplied instead of being added: Set m {\displaystyle m} to n {\displaystyle n} and i {\displaystyle i} to 0 ...
#PicoLisp
PicoLisp
(de mdr-mp (N) "Returns the solutions in a list, i.e., '(MDR MP)" (let MP 0 (while (< 1 (length N)) (setq N (apply * (mapcar format (chop N)))) (inc 'MP) ) (list N MP) ) )       # Get the MDR/MP of these nums. (setq Test-nums '(123321 7739 893 899998))   (let Fmt (6 5 5) (tab Fmt ...
http://rosettacode.org/wiki/Digital_root/Multiplicative_digital_root
Digital root/Multiplicative digital root
The multiplicative digital root (MDR) and multiplicative persistence (MP) of a number, n {\displaystyle n} , is calculated rather like the Digital root except digits are multiplied instead of being added: Set m {\displaystyle m} to n {\displaystyle n} and i {\displaystyle i} to 0 ...
#Phix
Phix
with javascript_semantics function mdr_mp(integer m) integer mp = 0 while m>9 do integer newm = 1 while m do newm *= remainder(m,10) m = floor(m/10) end while m = newm mp += 1 end while return {m,mp} end function constant tests = {123321,...
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...
http://rosettacode.org/wiki/Dot_product
Dot product
Task Create a function/use an in-built function, to compute the   dot product,   also known as the   scalar product   of two vectors. If possible, make the vectors of arbitrary length. As an example, compute the dot product of the vectors:   [1,  3, -5]     and   [4, -2, -1] If implementing the dot ...
#Factor
Factor
USING: kernel math.vectors sequences ;   : dot-product ( u v -- w ) 2dup [ length ] bi@ = [ v. ] [ "Vector lengths must be equal" throw ] if ;
http://rosettacode.org/wiki/Dot_product
Dot product
Task Create a function/use an in-built function, to compute the   dot product,   also known as the   scalar product   of two vectors. If possible, make the vectors of arbitrary length. As an example, compute the dot product of the vectors:   [1,  3, -5]     and   [4, -2, -1] If implementing the dot ...
#FALSE
FALSE
[[\1-$0=~][$d;2*1+\-ø\$d;2+\-ø@*@+]#]p: 3d: {Vectors' length} 1 3 5_ 4 2_ 1_ d;$1+ø@*p;!%. {Output: 3}
http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#D
D
import std.stdio;   void squeezable(string s, char rune) { writeln("squeeze: '", rune, "'"); writeln("old: <<<", s, ">>>, length = ", s.length);   write("new: <<<"); char last = '\0'; int len = 0; foreach (c; s) { if (c != last || c != rune) { write(c); len++; ...
http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#Delphi
Delphi
  program Determine_if_a_string_is_squeezable;   {$APPTYPE CONSOLE}   uses System.SysUtils;   var TestStrings: TArray<string> = ['', '''If I were two-faced, would I be wearing this one?'' --- Abraham Lincoln ', '..1111111111111111111111111111111111111111111111111111111111111117777888', 'I never give ''e...
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 ...
#11l
11l
V dxs = [-0.533, 0.27, 0.859, -0.043, -0.205, -0.127, -0.071, 0.275, 1.251, -0.231, -0.401, 0.269, 0.491, 0.951, 1.15, 0.001, -0.382, 0.161, 0.915, 2.08, -2.337, 0.034, -0.126, 0.014, 0.709, 0.129, -1.093, -0.483, -1.193, 0.02, -0.051, 0.047, -0.095, 0.695, 0.34, -0.182, 0.287, 0.213, -0.423,...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#F.23
F#
  // Descending primes. Nigel Galloway: April 19th., 2022 [2;3;5;7]::List.unfold(fun(n,i)->match n with []->None |_->let n=n|>List.map(fun(n,g)->[for n in n..9->(n+1,i*n+g)])|>List.concat in Some(n|>List.choose(fun(_,n)->if isPrime n then Some n else None),(n|>List.filter(fst>>(>)10),i*10)))([(4,3);(2,1);(8,7)],10) |...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#Factor
Factor
USING: grouping grouping.extras math math.combinatorics math.functions math.primes math.ranges prettyprint sequences sequences.extras ;   9 1 [a,b] all-subsets [ reverse 0 [ 10^ * + ] reduce-index ] [ prime? ] map-filter 10 "" pad-groups 10 group simple-table.
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#FreeBASIC
FreeBASIC
#include "isprime.bas" #include "sort.bas"   Dim As Double t0 = Timer Dim As Integer i, n, tmp, num, cant Dim Shared As Integer matriz(512) For i = 0 To 511 n = 0 tmp = i num = 9 While tmp If tmp And 1 Then n = n * 10 + num tmp = tmp Shr 1 num -= 1 Wend matriz(i) = n Next...
http://rosettacode.org/wiki/Determine_if_two_triangles_overlap
Determine if two triangles overlap
Determining if two triangles in the same plane overlap is an important topic in collision detection. Task Determine which of these pairs of triangles overlap in 2D:   (0,0),(5,0),(0,5)     and   (0,0),(5,0),(0,6)   (0,0),(0,5),(5,0)     and   (0,0),(0,5),(5,0)   (0,0),(5,0),(0,5)     and   (-10,0),(-5,0),(-1,6)...
#C
C
#include <errno.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h>   typedef struct { double x, y; } Point;   double det2D(const Point * const p1, const Point * const p2, const Point * const p3) { return p1->x * (p2->y - p3->y) + p2->x * (p3->y - p1->y) + p3->x * (p1->y - p2->y); }  ...
http://rosettacode.org/wiki/Determinant_and_permanent
Determinant and permanent
For a given matrix, return the determinant and the permanent of the matrix. The determinant is given by det ( A ) = ∑ σ sgn ⁡ ( σ ) ∏ i = 1 n M i , σ i {\displaystyle \det(A)=\sum _{\sigma }\operatorname {sgn}(\sigma )\prod _{i=1}^{n}M_{i,\sigma _{i}}} while the permanent is given by ...
#Common_Lisp
Common Lisp
  (defun determinant (rows &optional (skip-cols nil)) (let* ((result 0) (sgn -1)) (dotimes (col (length (car rows)) result) (unless (member col skip-cols) (if (null (cdr rows)) (return-from determinant (elt (car rows) col)) (incf result (* (setq sgn (- sgn)) (elt (car rows) col) ...
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#ALGOL_W
ALGOL W
begin  % integer division procedure  %  % sets c to a divided by b, returns true if the division was OK,  %  % false if there was division by zero  % logical procedure divideI ( integer value a, b; integer resul...
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#Arturo
Arturo
try? -> 3/0 else -> print "division by zero"
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#APL
APL
⊃⎕VFI{w←⍵⋄((w='-')/w)←'¯'⋄w}'152 -3.1415926 Foo123'   1 1 0
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#AppleScript
AppleScript
  -- isNumString :: String -> Bool on isNumString(s) try if class of s is string then set c to class of (s as number) c is real or c is integer else false end if on error false end try end isNumString       -- TEST on run   map(isNumStr...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_unique_characters
Determine if a string has all unique characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are unique   indicate if or which character is duplicated and where   display each string and its length   (as the strings are being ...
#AWK
AWK
  # syntax: GAWK -f DETERMINE_IF_A_STRING_HAS_ALL_UNIQUE_CHARACTERS.AWK BEGIN { for (i=0; i<=255; i++) { ord_arr[sprintf("%c",i)] = i } # build array[character]=ordinal_value n = split(",.,abcABC,XYZ ZYX,1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ",arr,",") for (i in arr) { width = max(width,length(arr[i])) ...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#Clojure
Clojure
  (defn collapse [s] (let [runs (partition-by identity s)] (apply str (map first runs))))   (defn run-test [s] (let [out (collapse s)] (str (format "Input: <<<%s>>> (len %d)\n" s (count s)) (format "becomes: <<<%s>>> (len %d)\n" out (count out)))))  
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#CLU
CLU
% Collapse a string collapse = proc (s: string) returns (string) out: array[char] := array[char]$[] last: char := '\000'   for c: char in string$chars(s) do if c ~= last then last := c array[char]$addh(out,c) end end return (string$ac2s(out)) end collapse   %...
http://rosettacode.org/wiki/Dice_game_probabilities
Dice game probabilities
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six. They roll their dice and sum the totals of the faces. The player with the highest total wins (i...
#Rust
Rust
// Returns a vector containing the number of ways each possible sum of face // values can occur. fn get_totals(dice: usize, faces: usize) -> Vec<f64> { let mut result = vec![1.0; faces + 1]; for d in 2..=dice { let mut tmp = vec![0.0; d * faces + 1]; for i in d - 1..result.len() { fo...
http://rosettacode.org/wiki/Dice_game_probabilities
Dice game probabilities
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six. They roll their dice and sum the totals of the faces. The player with the highest total wins (i...
#Sidef
Sidef
func combos(sides, n) { n || return [1] var ret = ([0] * (n*sides.max + 1)) combos(sides, n-1).each_kv { |i,v| v && for s in sides { ret[i + s] += v } } return ret }   func winning(sides1, n1, sides2, n2) { var (p1, p2) = (combos(sides1, n1), combos(sides2, n2)) var (win,loss,tie) = ...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_the_same_characters
Determine if a string has all the same characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are the same   indicate if or which character is different from the previous character   display each string and its length   (as the...
#C.2B.2B
C++
#include <iostream> #include <string>   void all_characters_are_the_same(const std::string& str) { size_t len = str.length(); std::cout << "input: \"" << str << "\", length: " << len << '\n'; if (len > 0) { char ch = str[0]; for (size_t i = 1; i < len; ++i) { if (str[i] != ch) { ...
http://rosettacode.org/wiki/Dining_philosophers
Dining philosophers
The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. It is a modification of a problem posed by Edsger Dijkstra. Five philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eating spaghetti. They eat at a rou...
#Java
Java
  package diningphilosophers;   import java.util.ArrayList; import java.util.Random; import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicInteger;   enum PhilosopherState { Get, Eat, Pon }   class Fork { public static final int ON_TABLE = -1; static int instances = 0; p...
http://rosettacode.org/wiki/Discordian_date
Discordian date
Task Convert a given date from the   Gregorian calendar   to the   Discordian calendar.
#J
J
require'dates' leap=: _1j1 * 0 -/@:= 4 100 400 |/ {.@] bs=: ((#:{.) + 0 j. *@[ * {:@]) +. disc=: ((1+0 73 bs[ +^:(58<]) -/@todayno@(,: 1 1,~{.)@]) ,~1166+{.@])~ leap
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...
#Julia
Julia
struct Digraph{T <: Real,U} edges::Dict{Tuple{U,U},T} verts::Set{U} end   function Digraph(edges::Vector{Tuple{U,U,T}}) where {T <: Real,U} vnames = Set{U}(v for edge in edges for v in edge[1:2]) adjmat = Dict((edge[1], edge[2]) => edge[3] for edge in edges) return Digraph(adjmat, vnames) end   vert...
http://rosettacode.org/wiki/Digital_root
Digital root
The digital root, X {\displaystyle X} , of a number, n {\displaystyle n} , is calculated: find X {\displaystyle X} as the sum of the digits of n {\displaystyle n} find a new X {\displaystyle X} by summing the digits of X {\displaystyle X} , repeating until X {\displ...
#Erlang
Erlang
-module( digital_root ).   -export( [task/0] ).   task() -> Ns = [N || N <- [627615, 39390, 588225, 393900588225]], Persistances = [persistance_root(X) || X <- Ns], [io:fwrite("~p has additive persistence ~p and digital root of ~p~n", [X, Y, Z]) || {X, {Y, Z}} <- lists:zip(Ns, Persistances)].     persistanc...
http://rosettacode.org/wiki/Digital_root/Multiplicative_digital_root
Digital root/Multiplicative digital root
The multiplicative digital root (MDR) and multiplicative persistence (MP) of a number, n {\displaystyle n} , is calculated rather like the Digital root except digits are multiplied instead of being added: Set m {\displaystyle m} to n {\displaystyle n} and i {\displaystyle i} to 0 ...
#PL.2FI
PL/I
multiple: procedure options (main); /* 29 April 2014 */   declare n fixed binary (31);   find_mdr: procedure; declare (mdr, mp, p) fixed binary (31);   mdr = n; do mp = 1 by 1 until (p <= 9); p = 1; do until (mdr = 0); /* Form product of the digits in mdr. */ p = mod(mdr, 10) * p; ...
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...
#Julia
Julia
using Combinatorics   function solve(n::Vector{<:AbstractString}, pred::Vector{<:Function}) rst = Vector{typeof(n)}(0) for candidate in permutations(n) if all(p(candidate) for p in predicates) push!(rst, candidate) end end return rst end   Names = ["Baker", "Cooper", "Fletche...
http://rosettacode.org/wiki/Dot_product
Dot product
Task Create a function/use an in-built function, to compute the   dot product,   also known as the   scalar product   of two vectors. If possible, make the vectors of arbitrary length. As an example, compute the dot product of the vectors:   [1,  3, -5]     and   [4, -2, -1] If implementing the dot ...
#Fantom
Fantom
class DotProduct { static Int dotProduct (Int[] a, Int[] b) { Int result := 0 [a.size,b.size].min.times |i| { result += a[i] * b[i] } return result }   public static Void main () { Int[] x := [1,2,3,4] Int[] y := [2,3,4]   echo ("Dot product of $x and $y is ${dotProduct(x...
http://rosettacode.org/wiki/Dot_product
Dot product
Task Create a function/use an in-built function, to compute the   dot product,   also known as the   scalar product   of two vectors. If possible, make the vectors of arbitrary length. As an example, compute the dot product of the vectors:   [1,  3, -5]     and   [4, -2, -1] If implementing the dot ...
#Forth
Forth
: vector create cells allot ; : th cells + ;   3 constant /vector /vector vector a /vector vector b   : dotproduct ( a1 a2 -- n) 0 tuck ?do -rot over i th @ over i th @ * >r rot r> + loop nip nip ;   : vector! cells over + swap ?do i ! 1 cells +loop ;   -5 3 1 a /vector vector! -1 -2 4 b /v...
http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#F.23
F#
  // Determine if a string is squeezable. Nigel Galloway: June 9th., 2020 let squeeze n i=if String.length n=0 then None else let fN=let mutable g=n.[0] in (fun n->if n=i && n=g then false else g<-n; true) let fG=n.[0..0]+System.String(n.[1..].ToCharArray()|>Array.filter fN) ...
http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#Factor
Factor
USING: formatting fry io kernel math sbufs sequences strings ; IN: rosetta-code.squeeze   : (squeeze) ( str c -- new-str ) [ unclip-slice 1string >sbuf ] dip '[ over last over [ _ = ] both? [ drop ] [ suffix! ] if ] reduce >string ;   : squeeze ( str c -- new-str ) over empty? [ 2drop "" ] [ (squeeze) ]...
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 ...
#Ada
Ada
with Ada.Numerics.Elementary_Functions; with Ada.Text_IO;   procedure Demings_Funnel is   type Float_List is array (Positive range <>) of Float;   Dxs : constant Float_List := (-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...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#Forth
Forth
: is-prime? \ n -- f ; \ Fast enough for this application DUP 1 AND IF \ n is odd DUP 3 DO DUP I DUP * < IF DROP -1 LEAVE THEN \ Leave loop if I**2 > n DUP I MOD 0= IF DROP 0 LEAVE THEN \ Leave loop if n%I is zero 2 +LOOP \ iterate over odd I only ELSE \ n is even ...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#Go
Go
package main   import ( "fmt" "rcu" "sort" "strconv" )   func combinations(a []int, k int) [][]int { n := len(a) c := make([]int, k) var combs [][]int var combine func(start, end, index int) combine = func(start, end, index int) { if index == k { t := make([]int, ...
http://rosettacode.org/wiki/Determine_if_two_triangles_overlap
Determine if two triangles overlap
Determining if two triangles in the same plane overlap is an important topic in collision detection. Task Determine which of these pairs of triangles overlap in 2D:   (0,0),(5,0),(0,5)     and   (0,0),(5,0),(0,6)   (0,0),(0,5),(5,0)     and   (0,0),(0,5),(5,0)   (0,0),(5,0),(0,5)     and   (-10,0),(-5,0),(-1,6)...
#C.23
C#
using System; using System.Collections.Generic;   namespace TriangleOverlap { class Triangle { public Tuple<double, double> P1 { get; set; } public Tuple<double, double> P2 { get; set; } public Tuple<double, double> P3 { get; set; }   public Triangle(Tuple<double, double> p1, Tuple<d...
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.
#11l
11l
fs:remove_file(‘output.txt’) fs:remove_dir(‘docs’) fs:remove_file(‘/output.txt’) fs:remove_dir(‘/docs’)
http://rosettacode.org/wiki/Determinant_and_permanent
Determinant and permanent
For a given matrix, return the determinant and the permanent of the matrix. The determinant is given by det ( A ) = ∑ σ sgn ⁡ ( σ ) ∏ i = 1 n M i , σ i {\displaystyle \det(A)=\sum _{\sigma }\operatorname {sgn}(\sigma )\prod _{i=1}^{n}M_{i,\sigma _{i}}} while the permanent is given by ...
#D
D
import std.algorithm, std.range, std.traits, permutations2, permutations_by_swapping1;   auto prod(Range)(Range r) nothrow @safe @nogc { return reduce!q{a * b}(ForeachType!Range(1), r); }   T permanent(T)(in T[][] a) nothrow @safe in { assert(a.all!(row => row.length == a[0].length)); } body { auto r...
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#AutoHotkey
AutoHotkey
ZeroDiv(num1, num2) { If ((num1/num2) != "") MsgBox % num1/num2 Else MsgBox, 48, Warning, The result is not valid (Divide By Zero). } ZeroDiv(0, 3) ; is ok ZeroDiv(3, 0) ; divize by zero alert
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#BASIC
BASIC
100 REM TRY 110 ONERR GOTO 200 120 D = - 44 / 0 190 END 200 REM CATCH 210 E = PEEK (222) < > 133 220 POKE 216,0: REM ONERR OFF 230 IF E THEN RESUME 240 CALL - 3288: REM RECOVER 250 PRINT "DIVISION BY ZERO"  
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#ARM_Assembly
ARM Assembly
    /* ARM assembly Raspberry PI */ /* program strNumber.s */   /* Constantes */ .equ STDIN, 0 @ Linux input console .equ STDOUT, 1 @ Linux output console .equ EXIT, 1 @ Linux syscall .equ READ, 3 @ Linux...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_unique_characters
Determine if a string has all unique characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are unique   indicate if or which character is duplicated and where   display each string and its length   (as the strings are being ...
#C
C
  #include<stdbool.h> #include<string.h> #include<stdlib.h> #include<stdio.h>   typedef struct positionList{ int position; struct positionList *next; }positionList;   typedef struct letterList{ char letter; int repititions; positionList* positions; struct letterList *next; }letterList;   letterL...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#Cowgol
Cowgol
include "cowgol.coh"; include "strings.coh";   # Collapse the string at in, and store the result in the given buffer sub collapse(in: [uint8], out: [uint8]) is var ch := [in]; in := @next in; loop if ch == 0 then [out] := 0; return; elseif [in] != ch then ...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#D
D
import std.stdio;   void collapsible(string s) { writeln("old: <<<", s, ">>>, length = ", s.length);   write("new: <<<"); char last = '\0'; int len = 0; foreach (c; s) { if (c != last) { write(c); len++; } last = c; } writeln(">>>, length = ", ...
http://rosettacode.org/wiki/Dice_game_probabilities
Dice game probabilities
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six. They roll their dice and sum the totals of the faces. The player with the highest total wins (i...
#Tcl
Tcl
foreach d0 {1 2 3 4 5 6} { foreach d1 {1 2 3 4 5 6} { ... foreach dN {1 2 3 4 5 6} { dict incr sum [::tcl::mathop::+ $n $d0 $d1 ... $DN] } ... } }
http://rosettacode.org/wiki/Dice_game_probabilities
Dice game probabilities
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six. They roll their dice and sum the totals of the faces. The player with the highest total wins (i...
#Vlang
Vlang
import math   fn min_of(x int, y int) int { if x < y { return x } return y }   fn throw_die(n_sides int, n_dice int, s int, mut counts []int) { if n_dice == 0 { counts[s]++ return } for i := int(1); i <= n_sides; i++ { throw_die(n_sides, n_dice - 1, s + i, mut cou...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_the_same_characters
Determine if a string has all the same characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are the same   indicate if or which character is different from the previous character   display each string and its length   (as the...
#Clojure
Clojure
  (defn check-all-chars-same [s] (println (format "String (%s) of len: %d" s (count s))) (let [num-same (-> (take-while #(= (first s) %) s) count)] (if (= num-same (count s)) (println "...all characters the same") (println (format "...character %d differs - it is 0x%x" ...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_the_same_characters
Determine if a string has all the same characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are the same   indicate if or which character is different from the previous character   display each string and its length   (as the...
#Common_Lisp
Common Lisp
(defun strequ (&rest str) (if (not str) (setf str (list "" " " "2" "333" ".55" "tttTTT" "4444 444k"))) (dolist (s str) (do ((i 0 (1+ i))) ((cond ((= i (length s)) (format t "\"~a\" [~d] : All characters are identical.~%" s (length s)) t) ...
http://rosettacode.org/wiki/Dining_philosophers
Dining philosophers
The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. It is a modification of a problem posed by Edsger Dijkstra. Five philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eating spaghetti. They eat at a rou...
#JoCaml
JoCaml
let random_wait n = Unix.sleep (Random.int n);; let print s m = Printf.printf "philosopher %s is %s\n" s m; flush(stdout);; let will_eat s = print s "eating"; random_wait 10;; let will_think s = print s "thinking"; random_wait 20; print s "hungry";;   (* a,b,c,d,e are thinking philosophers; ah,bh,ch,dh,eh are the sam...
http://rosettacode.org/wiki/Discordian_date
Discordian date
Task Convert a given date from the   Gregorian calendar   to the   Discordian calendar.
#Java
Java
import java.util.Calendar; import java.util.GregorianCalendar;   public class DiscordianDate { final static String[] seasons = {"Chaos", "Discord", "Confusion", "Bureaucracy", "The Aftermath"};   final static String[] weekday = {"Sweetmorn", "Boomtime", "Pungenday", "Prickle-Prickle", "Setting O...
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...
#Kotlin
Kotlin
// version 1.1.51   import java.util.TreeSet   class Edge(val v1: String, val v2: String, val dist: Int)   /** One vertex of the graph, complete with mappings to neighbouring vertices */ class Vertex(val name: String) : Comparable<Vertex> {   var dist = Int.MAX_VALUE // MAX_VALUE assumed to be infinity var pr...
http://rosettacode.org/wiki/Digital_root
Digital root
The digital root, X {\displaystyle X} , of a number, n {\displaystyle n} , is calculated: find X {\displaystyle X} as the sum of the digits of n {\displaystyle n} find a new X {\displaystyle X} by summing the digits of X {\displaystyle X} , repeating until X {\displ...
#F.23
F#
  //Find the Digital Root of An Integer - Nigel Galloway: February 1st., 2015 //This code will work with any integer type let inline digitalRoot N BASE = let rec root(p,n) = let s = sumDigits n BASE if s < BASE then (s,p) else root(p+1, s) root(LanguagePrimitives.GenericZero<_> + 1, N)  
http://rosettacode.org/wiki/Digital_root
Digital root
The digital root, X {\displaystyle X} , of a number, n {\displaystyle n} , is calculated: find X {\displaystyle X} as the sum of the digits of n {\displaystyle n} find a new X {\displaystyle X} by summing the digits of X {\displaystyle X} , repeating until X {\displ...
#Factor
Factor
USING: arrays formatting kernel math math.text.utils sequences ; IN: rosetta-code.digital-root   : digital-root ( n -- persistence root ) 0 swap [ 1 digit-groups dup length 1 > ] [ sum [ 1 + ] dip ] while first ;   : print-root ( n -- ) dup digital-root "%-12d has additive persistence %d and digital roo...
http://rosettacode.org/wiki/Digital_root/Multiplicative_digital_root
Digital root/Multiplicative digital root
The multiplicative digital root (MDR) and multiplicative persistence (MP) of a number, n {\displaystyle n} , is calculated rather like the Digital root except digits are multiplied instead of being added: Set m {\displaystyle m} to n {\displaystyle n} and i {\displaystyle i} to 0 ...
#Python
Python
try: from functools import reduce except: pass   def mdroot(n): 'Multiplicative digital root' mdr = [n] while mdr[-1] > 9: mdr.append(reduce(int.__mul__, (int(dig) for dig in str(mdr[-1])), 1)) return len(mdr) - 1, mdr[-1]   if __name__ == '__main__': print('Number: (MP, MDR)\n======...
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...
#K
K
  perm: {x@m@&n=(#?:)'m:!n#n:#x} filter: {y[& x'y]} reject: {y[& ~x'y]} adjacent: {1 = _abs (z?x) - (z?y)}   p: perm[`Baker `Cooper `Fletcher `Miller `Smith] p: reject[{`Cooper=x[0]}; p] p: reject[{`Baker=x[4]}; p] p: filter[{(x ? `Miller) > (x ? `Cooper)}; p] p: reject[{adjacent[`Smith; `Fletcher; x]}; p] p: reject[{a...
http://rosettacode.org/wiki/Dot_product
Dot product
Task Create a function/use an in-built function, to compute the   dot product,   also known as the   scalar product   of two vectors. If possible, make the vectors of arbitrary length. As an example, compute the dot product of the vectors:   [1,  3, -5]     and   [4, -2, -1] If implementing the dot ...
#Fortran
Fortran
program test_dot_product   write (*, '(i0)') dot_product ([1, 3, -5], [4, -2, -1])   end program test_dot_product
http://rosettacode.org/wiki/Dot_product
Dot product
Task Create a function/use an in-built function, to compute the   dot product,   also known as the   scalar product   of two vectors. If possible, make the vectors of arbitrary length. As an example, compute the dot product of the vectors:   [1,  3, -5]     and   [4, -2, -1] If implementing the dot ...
#Frink
Frink
dotProduct[v1, v2] := { if length[v1] != length[v2] { println["dotProduct: vectors are of different lengths."] return undef }   return sum[map[{|c1,c2| c1 * c2}, zip[v1, v2]]] }
http://rosettacode.org/wiki/Determine_if_a_string_is_squeezable
Determine if a string is squeezable
Determine if a character string is   squeezable. And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character). This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead...
#Fortran
Fortran
  program main implicit none character(len=:),allocatable :: strings(:)   strings=[ character(len=72) :: & '', & '"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln', & '..1111111111111111111111111111111111111111111111111111111111111117777888', & 'I never give ''em hell, I just tell the truth, and...
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 ...
#D
D
import std.stdio, std.math, std.algorithm, std.range, std.typecons;   auto mean(T)(in T[] xs) pure nothrow @nogc { return xs.sum / xs.length; }   auto stdDev(T)(in T[] xs) pure nothrow { immutable m = xs.mean; return sqrt(xs.map!(x => (x - m) ^^ 2).sum / xs.length); }   alias TF = double function(in double,...
http://rosettacode.org/wiki/Department_numbers
Department numbers
There is a highly organized city that has decided to assign a number to each of their departments:   police department   sanitation department   fire department Each department can have a number between   1   and   7   (inclusive). The three department numbers are to be unique (different from each other) and mu...
#11l
11l
print(‘Police Sanitation Fire’) print(‘----------------------------------’)   L(police) (2..6).step(2) L(sanitation) 1..7 L(fire) 1..7 I police!=sanitation & sanitation!=fire & fire!=police & police+fire+sanitation==12 print(police"\t\t"sanitation"\t\t"fire)
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#J
J
extend=: {{ y;y,L:0(1+each i.1-{:y)}} ($~ q:@$)(#~ 1 p: ])10#.&>([:~.@;extend each)^:# >:i.9 2 3 31 43 41 431 421 5 53 541 521 5431 61 653 643 641 631 6521 6421 7 73 71 761 751 743 7643 7621 7541 7321 76543 76541 76421 75431 764321 83 ...
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#Julia
Julia
using Combinatorics using Primes   function descendingprimes() return sort!(filter(isprime, [evalpoly(10, x) for x in powerset([1, 2, 3, 4, 5, 6, 7, 8, 9]) if !isempty(x)])) end   foreach(p -> print(rpad(p[2], 10), p[1] % 10 == 0 ? "\n" : ""), enumerate(descendingprimes()))  
http://rosettacode.org/wiki/Descending_primes
Descending primes
Generate and show all primes with strictly descending decimal digits. See also OEIS:A052014 - Primes with distinct digits in descending order Related Ascending primes
#Lua
Lua
local function is_prime(n) if n < 2 then return false end if n % 2 == 0 then return n==2 end if n % 3 == 0 then return n==3 end for f = 5, n^0.5, 6 do if n%f==0 or n%(f+2)==0 then return false end end return true end   local function descending_primes() local digits, candidates, primes = {9,8,7,6,5,4,...
http://rosettacode.org/wiki/Determine_if_two_triangles_overlap
Determine if two triangles overlap
Determining if two triangles in the same plane overlap is an important topic in collision detection. Task Determine which of these pairs of triangles overlap in 2D:   (0,0),(5,0),(0,5)     and   (0,0),(5,0),(0,6)   (0,0),(0,5),(5,0)     and   (0,0),(0,5),(5,0)   (0,0),(5,0),(0,5)     and   (-10,0),(-5,0),(-1,6)...
#C.2B.2B
C++
#include <vector> #include <iostream> #include <stdexcept> using namespace std;   typedef std::pair<double, double> TriPoint;   inline double Det2D(TriPoint &p1, TriPoint &p2, TriPoint &p3) { return +p1.first*(p2.second-p3.second) +p2.first*(p3.second-p1.second) +p3.first*(p1.second-p2.second); }   void CheckTriW...
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.
#8th
8th
  "input.txt" f:rm drop "/input.txt" f:rm drop "docs" f:rmdir drop "/docs" f:rmdir drop  
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.
#AArch64_Assembly
AArch64 Assembly
  /* ARM assembly AARCH64 Raspberry PI 3B */ /* program deleteFic64.s */   /*******************************************/ /* Constantes file */ /*******************************************/ /* for this file see task include a file in language AArch64 assembly*/ .include "../includeConstantesAR...
http://rosettacode.org/wiki/Determinant_and_permanent
Determinant and permanent
For a given matrix, return the determinant and the permanent of the matrix. The determinant is given by det ( A ) = ∑ σ sgn ⁡ ( σ ) ∏ i = 1 n M i , σ i {\displaystyle \det(A)=\sum _{\sigma }\operatorname {sgn}(\sigma )\prod _{i=1}^{n}M_{i,\sigma _{i}}} while the permanent is given by ...
#Delphi
Delphi
  program Determinant_and_permanent;   {$APPTYPE CONSOLE}   uses System.SysUtils;   type TMatrix = TArray<TArray<Double>>;   function Minor(a: TMatrix; x, y: Integer): TMatrix; begin var len := Length(a) - 1; SetLength(result, len, len); for var i := 0 to len - 1 do begin for var j := 0 to len - 1 do ...
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#Batch_File
Batch File
@echo off set /a dummy=5/0 2>nul   if %errorlevel%==1073750993 echo I caught a division by zero operation... exit /b 0
http://rosettacode.org/wiki/Detect_division_by_zero
Detect division by zero
Task Write a function to detect a   divide by zero error   without checking if the denominator is zero.
#BQN
BQN
Div ← {∨´"∞"‿"NaN"≡¨<•Fmt𝕩}◶⊢‿"Division by 0"÷   •Show 5 Div 0 •Show 5 Div 5 •Show 0 Div 0
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#Arturo
Arturo
print numeric? "hello world" print numeric? "1234" print numeric? "1234 hello world" print numeric? "12.34" print numeric? "!#@$" print numeric? "-1.23"
http://rosettacode.org/wiki/Determine_if_a_string_is_numeric
Determine if a string is numeric
Task Create a boolean function which takes in a string and tells whether it is a numeric string (floating point and negative numbers included) in the syntax the language uses for numeric literals or numbers converted from strings. Other tasks related to string operations: Metrics Array length String length Cop...
#AutoHotkey
AutoHotkey
list = 0 .14 -5.2 ten 0xf Loop, Parse, list, %A_Space% MsgBox,% IsNumeric(A_LoopField) Return   IsNumeric(x) { If x is number Return, 1 Else Return, 0 }   ;Output: 1 1 1 0 1
http://rosettacode.org/wiki/Determine_if_a_string_has_all_unique_characters
Determine if a string has all unique characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are unique   indicate if or which character is duplicated and where   display each string and its length   (as the strings are being ...
#C.23
C#
using System; using System.Linq;   public class Program { static void Main { string[] input = {"", ".", "abcABC", "XYZ ZYX", "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ"}; foreach (string s in input) { Console.WriteLine($"\"{s}\" (Length {s.Length}) " + string.Join(", ", ...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#Delphi
Delphi
  program Determine_if_a_string_is_collapsible;   {$APPTYPE CONSOLE}   uses System.SysUtils;   procedure collapsible(s: string); var c, last: char; len: Integer; begin writeln('old: <<<', s, '>>>, length = ', s.length); write('new: <<<'); last := #0; len := 0; for c in s do begin if c <> last then...
http://rosettacode.org/wiki/Determine_if_a_string_is_collapsible
Determine if a string is collapsible
Determine if a character string is   collapsible. And if so,   collapse the string   (by removing   immediately repeated   characters). If a character string has   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s). An   immediatel...
#F.23
F#
  // Collapse a String. Nigel Galloway: June 9th., 2020 //As per the task description a function which 'determines if a character string is collapsible' by testing if any consecutive characters are the same. let isCollapsible n=n|>Seq.pairwise|>Seq.tryFind(fun(n,g)->n=g) //As per the task description a function which '...
http://rosettacode.org/wiki/Dice_game_probabilities
Dice game probabilities
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six. They roll their dice and sum the totals of the faces. The player with the highest total wins (i...
#Wren
Wren
var throwDie // recursive throwDie = Fn.new { |nSides, nDice, s, counts| if (nDice == 0) { counts[s] = counts[s] + 1 return } for (i in 1..nSides) throwDie.call(nSides, nDice-1, s + i, counts) }   var beatingProbability = Fn.new { |nSides1, nDice1, nSides2, nDice2| var len1 = (nSides1 + ...
http://rosettacode.org/wiki/Determine_if_a_string_has_all_the_same_characters
Determine if a string has all the same characters
Task Given a character string   (which may be empty, or have a length of zero characters):   create a function/procedure/routine to:   determine if all the characters in the string are the same   indicate if or which character is different from the previous character   display each string and its length   (as the...
#D
D
import std.stdio;   void analyze(string s) { writefln("Examining [%s] which has a length of %d:", s, s.length); if (s.length > 1) { auto b = s[0]; foreach (i, c; s[1..$]) { if (c != b) { writeln(" Not all characters in the string are the same."); wr...
http://rosettacode.org/wiki/Dining_philosophers
Dining philosophers
The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. It is a modification of a problem posed by Edsger Dijkstra. Five philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eating spaghetti. They eat at a rou...
#Julia
Julia
  mutable struct Philosopher name::String hungry::Bool righthanded::Bool rightforkheld::Channel leftforkheld::Channel function Philosopher(name, leftfork, rightfork) this = new() this.name = name this.hungry = rand([false, true]) # not specified so start as either ...
http://rosettacode.org/wiki/Discordian_date
Discordian date
Task Convert a given date from the   Gregorian calendar   to the   Discordian calendar.
#JavaScript
JavaScript
  /** * All Hail Discordia! - this script prints Discordian date using system date. * * lang: JavaScript * author: jklu * contributors: JamesMcGuigan * * changelog: * - Modified to return same output syntax as unix ddate + module.exports - James McGuigan, 2/Chaos/3183 * * source: https://rosettacode.org/wiki/...
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...
#Lua
Lua
-- Graph definition local edges = { a = {b = 7, c = 9, f = 14}, b = {c = 10, d = 15}, c = {d = 11, f = 2}, d = {e = 6}, e = {f = 9} }   -- Fill in paths in the opposite direction to the stated edges function complete (graph) for node, edges in pairs(graph) do for edge, distance in pairs(...