qsort

void mQsort(int *arr, int left, int right)
{

    if (left < right)
    {
        int l = left, r = right;
        int mid = arr[(l+r) / 2];
        do
        {
            while (arr[l] < mid) // for reverse: while (arr[l] > mid)
                l++;
            while (arr[r] > mid) // for reverse: while (arr[r] < mid)
                r--;

            if (l <= r)
            {
                int c = arr[l];
                arr[l] = arr[r];
                arr[r] = c;
                l++;
                r--;
            }
        } while (l <= r);

        mQsort(arr, left, r);
        mQsort(arr, l, right);
    }
}