如果用while循环需要这样

#include<iostream>
#include<cstring>


using namespace std;
const int N = 100010;
int q[N];
int n;
void quick_sort(int l, int r)
{
    if (l >= r) return;
    int x = q[(l + r) >> 1], i = l - 1, j = r + 1;
    while(i < j)
    {
        while(q[++i] < x);
        while(q[--j] > x);
        if (i < j) swap(q[i], q[j]);
    }

    quick_sort(l, j);
    quick_sort(j + 1, r);
}

int main()
{
    scanf("%d", &n);
    for (int i = 0; i < n;i++) scanf("%d", &q[i]);
    quick_sort(0, n - 1);
    for (int i = 0; i < n; i++) printf("%d ", q[i]);
    return 0;
}