Just another update

Task/Knuth-shuffle/00DESCRIPTION

@@ -1 +1,2 @@
-Implement the [[wp:Knuth shuffle|Knuth shuffle]] (a.k.a. the Fisher-Yates shuffle) for an integer array (or, if possible, an array of any type). The Knuth shuffle is used to create a random permutation of an array.
+Implement the [[wp:Knuth shuffle|Knuth shuffle]] (a.k.a. the Fisher-Yates shuffle) for an integer array (or, if possible, an array of any type).
+The Knuth shuffle is used to create a random permutation of an array.

Task/Knuth-shuffle/Eiffel/knuth-shuffle.e

@@ -0,0 +1,46 @@
+class
+	APPLICATION
+inherit
+	ARGUMENTS
+create
+	make
+
+feature {NONE} -- Initialization
+
+	make
+		do
+			test:= <<1,2,3,4,5,6,7>>
+			io.put_string ("Initial: ")
+			across test as t loop   io.put_string (t.item.out + " ") end
+			create testresult.make_empty
+			testresult:= shuffle (test)
+			io.put_string ("%NShuffled: ")
+			across testresult as t loop io.put_string (t.item.out + " ") end
+
+		end
+
+        test: ARRAY[INTEGER]
+        testresult: ARRAY[INTEGER]
+
+	shuffle(ar:ARRAY[INTEGER]): ARRAY[INTEGER]
+	local
+		i,j:INTEGER
+		ith: INTEGER
+		random: V_RANDOM
+	do
+		create random
+		from
+			i:=ar.count
+		until
+			i=2
+		loop
+			j:=random.bounded_item (1, i)
+			ith:= ar[i]
+			ar[i]:= ar[j]
+			ar[j]:= ith
+			random.forth
+			i:=i-1
+		end
+		Result:= ar
+	end
+end

Task/Knuth-shuffle/Frink/knuth-shuffle.frink

@@ -0,0 +1,2 @@
+a = [1,2,3]
+a.shuffle[]

Task/Knuth-shuffle/GAP/knuth-shuffle.gap

@@ -1,19 +1,19 @@
 # Return the list L after applying Knuth shuffle. GAP also has the function Shuffle, which does the same.
 ShuffleAlt := function(a)
-   local i, j, n, t;
-   n := Length(a);
-   for i in [n, n - 1 .. 2] do
-      j := Random(1, i);
-      t := a[i];
-      a[i] := a[j];
-      a[j] := t;
-   od;
-   return a;
+    local i, j, n, t;
+    n := Length(a);
+    for i in [n, n - 1 .. 2] do
+        j := Random(1, i);
+        t := a[i];
+        a[i] := a[j];
+        a[j] := t;
+    od;
+    return a;
 end;
 
 # Return a "Permutation" object (a permutation of 1 .. n).
 # They are printed in GAP, in cycle decomposition form.
-PermShuffle := n -> PermListList([1 .. n], Shuffle([1 .. n]));
+PermShuffle := n -> PermList(ShuffleAlt([1 .. n]));
 
 ShuffleAlt([1 .. 10]);
 # [ 4, 7, 1, 5, 8, 2, 6, 9, 10, 3 ]

Task/Knuth-shuffle/Objective-C/knuth-shuffle.m

@@ -0,0 +1,22 @@
+#import <Foundation/Foundation.h>
+
+@interface NSMutableArray (KnuthShuffle)
+- (void)knuthShuffle;
+@end
+@implementation NSMutableArray (KnuthShuffle)
+- (void)knuthShuffle {
+  for (NSUInteger i = self.count-1; i > 0; i--) {
+    NSUInteger j = arc4random_uniform(i+1);
+    [self exchangeObjectAtIndex:i withObjectAtIndex:j];
+  }
+}
+@end
+
+int main() {
+  @autoreleasepool {
+    NSMutableArray *x = [NSMutableArray arrayWithObjects:@0, @1, @2, @3, @4, @5, @6, @7, @8, @9, nil];
+    [x knuthShuffle];
+    NSLog(@"%@", x);
+  }
+  return 0;
+}

Task/Knuth-shuffle/UNIX-Shell/knuth-shuffle.sh

@@ -15,7 +15,6 @@ function shuffle {
 	done
 }
 
-
 # Test program.
 set -A array 11 22 33 44 55 66 77 88 99 110
 shuffle