Another update from ingydotnet^djgoku

Task/Sorting-algorithms-Quicksort/ALGOL-68/sorting-algorithms-quicksort-1.alg

@@ -1,47 +1,62 @@
-PROC partition =(REF [] DATA array, PROC (REF DATA, REF DATA) BOOL cmp)INT: (
-  INT begin:=LWB array;
-  INT end:=UPB array;
-  WHILE begin < end DO
-     WHILE begin < end DO
-      IF cmp(array[begin], array[end]) THEN
-        DATA tmp=array[begin];
-        array[begin]:=array[end];
-        array[end]:=tmp;
-        GO TO break while decr end
-      FI;
-      end -:= 1
-    OD;
-    break while decr end: SKIP;
-     WHILE begin < end DO
-      IF cmp(array[begin], array[end]) THEN
-        DATA tmp=array[begin];
-         array[begin]:=array[end];
-        array[end]:=tmp;
-        GO TO break while incr begin
-      FI;
-      begin +:= 1
-     OD;
-     break while incr begin: SKIP
-  OD;
-  begin
+#--- Swap function ---#
+PROC swap = (REF []INT array, INT first, INT second) VOID:
+(
+    INT temp := array[first];
+    array[first] := array[second];
+    array[second]:= temp
 );
 
-PROC qsort=(REF [] DATA array, PROC (REF DATA, REF DATA) BOOL cmp)VOID: (
-  IF LWB array < UPB array THEN
-    INT i := partition(array, cmp);
-    PAR ( # remove PAR for single threaded sort #
-      qsort(array[:i-1], cmp),
-      qsort(array[i+1:], cmp)
-    )
+#--- Quick sort 3 arg function ---#
+PROC quick = (REF [] INT array, INT first, INT last) VOID:
+(
+    INT smaller := first + 1,
+        larger  := last,
+        pivot   := array[first];
+
+    WHILE smaller <= larger DO
+        WHILE array[smaller] < pivot   AND   smaller < last DO
+            smaller +:= 1
+        OD;
+        WHILE array[larger]  > pivot   AND   larger > first DO
+            larger  -:= 1
+        OD;
+        IF smaller < larger THEN
+            swap(array, smaller, larger);
+            smaller +:= 1;
+            larger  -:= 1
+        ELSE
+            smaller +:= 1
+        FI
+    OD;
+
+    swap(array, first, larger);
+
+    IF first < larger-1 THEN
+        quick(array, first, larger-1)
+    FI;
+    IF last > larger +1 THEN
+        quick(array, larger+1, last)
+    FI
+);
+
+#--- Quick sort 1 arg function ---#
+PROC quicksort = (REF []INT array) VOID:
+(
+  IF UPB array > 1 THEN
+    quick(array, 1, UPB array)
   FI
 );
 
-MODE DATA = INT;
-PROC cmp=(REF DATA a,b)BOOL: a>b;
+#***************************************************************#
+main:
+(
+    [10]INT a;
+    FOR i FROM 1 TO UPB a DO
+        a[i] := ROUND(random*1000)
+    OD;
 
-main:(
-  []DATA const l=(5,4,3,2,1);
-  [UPB const l]DATA l:=const l;
-  qsort(l,cmp);
-  printf(($g(3)$,l))
+    print(("Before:", a));
+    quicksort(a);
+    print((newline, newline));
+    print(("After: ", a))
 )