qsort-rec.s
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# recursive quicksort
array: [100] { key: int; data: real };
size: int;
qsort = map (l, r) -> () [
(i, j) := (l, r);
x := array[(l+r)/2];
more := true;
* [ more -> * [ array[i].key < x.key -> i := i+1 ];
* [ x.key < array[j].key -> j := j-1 ];
? [ i <= j -> (array[i], array[j]) := (array[j], array[i]);
(i, j) := (i+1, j-1) ];
more := i <= j ];
? [ l<j -> qsort (l, j) ];
? [ i<r -> qsort (i, r) ]
];
readData = map () -> () [
size := readInt ();
i := 0;
* [ i<size -> array[i].key := readInt(); i := i+1 ];
(i, j, k) := (0, 0.5, 1.5);
* [ i<size -> array[i].data := j+k;
(j, k) := (k, j+k);
i := i+1 ]
];
writeData = map () -> () [
writeChar(10);
i := 0;
* [ i<size -> writeInt(array[i].key);
writeChar(32);
writeReal(array[i].data);
writeChar(10);
i := i+1 ]
];
program = map () -> () [
readData ();
? [ readBool () -> qsort (0, size-1) ];
writeData ()
]