Time for an 2014 update…

Task/Knuth-shuffle/D/knuth-shuffle-1.d

@@ -1,7 +1,7 @@
-import std.stdio, std.random;
-
 void main() {
+    import std.stdio, std.random;
+
     auto a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
-    a.randomShuffle();
-    writeln(a);
+    a.randomShuffle;
+    a.writeln;
 }

Task/Knuth-shuffle/D/knuth-shuffle-2.d

@@ -1,12 +1,14 @@
-import std.stdio, std.algorithm, std.random;
+import std.stdio, std.algorithm, std.random, std.range;
 
-void shuffle(Range)(Range r) {
-    foreach_reverse (i; 1 .. r.length)
-        swap(r[i], r[uniform(0, i + 1)]);
+void knuthShuffle(Range)(Range r)
+if (isRandomAccessRange!Range && hasLength!Range &&
+    hasSwappableElements!Range) {
+    foreach_reverse (immutable i; 1 .. r.length)
+        r[i].swap(r[uniform(0, i + 1)]);
 }
 
 void main() {
     auto a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
-    a.shuffle();
-    writeln(a);
+    a.knuthShuffle;
+    a.writeln;
 }

Task/Knuth-shuffle/NetRexx/knuth-shuffle-2.netrexx

@@ -0,0 +1,34 @@
+/* NetRexx ------------------------------------------------------------
+* 08.01.2014 Walter Pachl modified to show state development a la Rexx
+*--------------------------------------------------------------------*/
+options replace format comments java crossref savelog symbols nobinary
+
+import java.util.List
+
+cards = [String '1','2','3','4','5','6','7','8','9','10']
+cardsLen = cards.length
+deck = ArrayList(cardsLen)
+loop c_ = 0 to cardsLen - 1
+  deck.add(String(cards[c_]))
+  end c_
+
+showHand(deck,'In ')
+deck = ArrayList shuffle(deck)
+showHand(deck,'Out')
+return
+
+method shuffle(deck = List) public static binary returns List
+  rn = Random()
+  dl = deck.size
+  loop i_ = dl - 1 to 1 by -1
+    j_ = rn.nextInt(i_)
+    __ = deck.get(i_)
+    deck.set(i_, deck.get(j_))
+    deck.set(j_, __)
+    say i_ j_ ArrayList(deck.subList(0,i_+1)).toString
+    end i_
+  return deck
+
+method showHand(deck = ArrayList,tag=REXX) public static binary
+  say tag ArrayList(deck.subList(0,deck.size)).toString
+  return

Task/Knuth-shuffle/PL-I/knuth-shuffle-2.pli

@@ -0,0 +1,23 @@
+ kn: Proc Options(main);
+ /*--------------------------------------------------------------------
+ * 07.01.2014 Walter Pachl  translated from REXX version 2
+ * Iteration i: only the first i elements are candidates for swapping
+ *-------------------------------------------------------------------*/
+ Dcl T(10) Bin Fixed(15) Init(1,2,3,4,5,6,7,8,9,10);
+ Dcl (i,j,temp) Bin Fixed(15) init(0);
+ Dcl h Char(6);
+ Call show('In',10);                   /* show start                 */
+ do i = 10 To 2 By -1;                 /* shuffle                    */
+   j=random()*i+1;
+   Put string(h)Edit(i,j)(f(2),f(3));
+   temp=t(i); t(i)=t(j); t(j)=temp;    /* t(i) <-> t(j)              */
+   Call show(h,i);                     /* show intermediate states   */
+   end;
+ Call show('Out',10);                  /* show final state           */
+
+ show: Proc(txt,n);
+ Dcl txt Char(*);
+ Dcl n   Bin Fixed(15);
+ Put Edit(txt,(t(k) do k=1 To n))(Skip,a(7),10(f(3)));
+ End;
+ end;

Task/Knuth-shuffle/REXX/knuth-shuffle-1.rexx

@@ -0,0 +1,23 @@
+/*REXX program shuffles a deck of playing cards using the Knuth shuffle.*/
+rank='A 2 3 4 5 6 7 8 9 10 J Q K'      /*pips  of the playing cards.    */
+suit='♣♠♦♥'                            /*suit   "  "     "      "       */
+parse arg seed .; if seed\=='' then call random ,,seed  /*repeatability?*/
+say '────────────────── getting a new deck out of the box ···'
+deck.1='highJoker'                     /*good decks have a color joker, */
+deck.2='lowJoker'                      /*··· and a black & white joker. */
+cards=2                                /*now, two cards are in the deck.*/
+               do j     =1  for length(suit)
+                    do k=1  for words(rank);            cards=cards+1
+                    deck.cards=substr(suit,j,1)word(rank,k)
+                    end  /*k*/
+               end       /*j*/
+call showDeck
+say '────────────────── shuffling' cards "cards ···"
+     do s=cards  by -1  to 2;            rand=random(1,s)
+     parse value   deck.rand   deck.s    with     deck.s  deck.rand
+                                       /* [↑] swap two cards in the deck*/
+     end   /*s*/
+call showDeck
+exit                                   /*stick a fork in it, we're done.*/
+/*──────────────────────────────────SHOWDECK subroutine─────────────────*/
+showDeck: _=;  do m=1 for cards; _=_ deck.m; end /*m*/; say _; say; return

Task/Knuth-shuffle/REXX/knuth-shuffle-2.rexx

@@ -0,0 +1,30 @@
+/*REXX program shuffles a deck of playing cards using the Knuth shuffle.*/
+rank = 'ace deuce trey 4 5 6 7 8 9 10 jack queen king'  /*use pip names.*/
+suit = 'club spade diamond heart'                       /* "  suit   "  */
+say '────────────────── getting a new deck out of the box ···'
+deck.1 = '  color joker'               /*good decks have a color joker, */
+deck.2 = '    b&w joker'               /*··· and a black & white joker. */
+cards=2                                /*now, two cards are in the deck.*/
+          do j     =1  for words(suit)
+               do k=1  for words(rank);  cards=cards+1   /*bump counter.*/
+               deck.cards=right(word(suit,j),7)  word(rank,k)  /*assign.*/
+               end  /*k*/
+          end       /*j*/
+
+call showDeck 'ace'                    /*inserts blank when ACE is found*/
+say '────────────────── shuffling' cards "cards ···"
+
+  do s=cards  by -1  to 2; rand=random(1,s) /*get random number for swap*/
+  _=deck.rand; deck.rand=deck.s; deck.s=_   /*swap 2 cards in card deck.*/
+  end   /*s*/
+
+call showDeck
+exit                                   /*stick a fork in it, we're done.*/
+/*──────────────────────────────────SHOWDECK subroutine─────────────────*/
+showDeck: parse arg break;    say       /*get sep card, shows blank line*/
+    do m=1  for cards                   /*traipse through the deck.     */
+    if pos(break,deck.m)\==0  then say  /*a blank: easier to read cards.*/
+    say 'card' right(m,2) '───►' deck.m /*display a particular card.    */
+    end   /*m*/
+say                                     /*show a trailing blank line.   */
+return

Task/Knuth-shuffle/REXX/knuth-shuffle-3.rexx

@@ -0,0 +1,23 @@
+/* REXX ---------------------------------------------------------------
+* 05.01.2014 Walter Pachl
+*            borrow one improvement from version 1
+* 06.01.2014 removed    -"-  (many tests cost more than few "swaps")
+*--------------------------------------------------------------------*/
+Call random ,,123456                   /* seed for random            */
+Do i=1 To 10; a.i=i; End;              /* fill array                 */
+Call show 'In',10                      /* show start                 */
+do i = 10 To 2 By -1                   /* shuffle                    */
+  j=random(i-1)+1;
+  h=right(i,2) right(j,2)
+  Parse Value a.i a.j With a.j a.i     /* a.i <-> a.j                */
+  Call show h,i                        /* show intermediate states   */
+  end;
+Call show 'Out',10                     /* show fomaö state           */
+Exit
+
+show: Procedure Expose a.
+Parse Arg txt,n
+ol=left(txt,6);
+Do k=1 To n; ol=ol right(a.k,2); End
+Say ol
+Return

Task/Knuth-shuffle/REXX/knuth-shuffle.rexx

@@ -1,37 +0,0 @@
-/*REXX program shuffles a deck of playing cards using the Knuth shuffle.*/
-rank='ace deuce trey 4 5 6 7 8 9 10 jack queen king'
-suit='club spade diamond heart'
-say '────────────────── getting a new deck out of the box...'
-deck.1='  color joker'                 /*good decks have a color joker, */
-deck.2='    b&w joker'                 /*∙∙∙ and a black & white joker. */
-cards=2                                /*now, two cards are in the deck.*/
-           do j     =1  for words(suit)
-                do k=1  for words(rank)
-                cards=cards+1
-                deck.cards=right(word(suit,j),7)  word(rank,k)
-                end  /*k*/
-           end       /*j*/
-
-call showDeck 'ace'                    /*inserts blank when ACE is found*/
-say '────────────────── shuffling' cards "cards..."
-
-   do s=cards  by -1  to 1;            rand=random(1,s)
-   if rand\==s  then do                /*swap two cards in the card deck*/
-                     _=deck.rand
-                     deck.rand=deck.s
-                     deck.s=_
-                     end
-   end   /*s*/
-
-call showDeck
-say '────────────────── ready to play schafkopf  (take out jokers first).'
-exit                                   /*stick a fork in it, we're done.*/
-
-/*──────────────────────────────────SHOWDECK subroutine─────────────────*/
-showDeck: parse arg break;    say
-      do m=1  for cards
-      if pos(break,deck.m)\==0  then say   /*blank, easier to read cards*/
-      say 'card' right(m,2) '───►' deck.m
-      end   /*m*/
-say
-return

Task/Knuth-shuffle/Rust/knuth-shuffle.rust

@@ -0,0 +1,22 @@
+use std::iter;
+use std::rand;
+use std::rand::Rng;
+use std::vec;
+
+fn knuth_shuffle<T>(v: &mut [T]) {
+    let mut rng = rand::rng();
+    let l = v.len();
+
+    for n in iter::range(0, l) {
+        let i = rng.gen_range(0, l - n);
+        v.swap(i, l - n - 1);
+    }
+}
+
+fn main() {
+    let mut v = vec::from_fn(10, |i| i);
+
+    println!("before: {:?}", v);
+    knuth_shuffle(v);
+    println!("after:  {:?}", v);
+}