Quicksort in AWK

quicksort.awk

function quicksort(a, left, right,  pivot, left_new, right_new) {
    if (left >= right) return;

    pivot = a[left + int((right - left) / 2)];
    left_new = left;
    right_new = right;

    do {
        while (a[left_new] < pivot) left_new += 1;
        while (pivot < a[right_new]) right_new -= 1;
        if (left_new <= right_new) {
          tmp=a[left_new];
          a[left_new]=a[right_new];
          a[right_new]=tmp;

          left_new++;
          right_new--;
        }
    } while (left_new <= right_new);

    quicksort(a, left, right_new);
    quicksort(a, left_new, right);
}