Sorting algorithms/Quicksort: Difference between revisions

==[[Seed7]]==

[[Category:Seed7]]

<pre>

const proc: quickSort (inout array elemType: arr, in integer: left, in integer: right) is func

local

var elemType: compare_elem is elemType.value;

var integer: less_idx is 0;

var integer: greater_idx is 0;

var elemType: help is elemType.value;

begin

if right > left then

compare_elem := arr[right];

less_idx := pred(left);

greater_idx := right;

repeat

repeat

incr(less_idx);

until arr[less_idx] >= compare_elem;

repeat

decr(greater_idx);

until arr[greater_idx] <= compare_elem or greater_idx = left;

if less_idx < greater_idx then

help := arr[less_idx];

arr[less_idx] := arr[greater_idx];

arr[greater_idx] := help;

end if;

until less_idx >= greater_idx;

arr[right] := arr[less_idx];

arr[less_idx] := compare_elem;

quickSort(arr, left, pred(less_idx));

quickSort(arr, succ(less_idx), right);

end if;

end func;

const proc: quickSort (inout array elemType: arr) is func

begin

quickSort(arr, 1, length(arr));

end func;

</pre>

Original source: [http://seed7.sourceforge.net/algorith/sorting.htm#quickSort]