qsort的用法

#include <cstdio>
#include <cmath>
#include <climits>
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;

#define maxn 100
int a[100];
int n;
int cmp(const void *x, const void *y){
return *(int *)x - *(int *)y;
}
int main(void){
int i;
while(scanf("%d", &n) == 1)
{
for (i = 0; i < n; ++i)
{
scanf("%d", &a[i]);
}
//     sort(a, a + n);
qsort(a, n, sizeof(int), cmp);
for (i = 0; i < n; ++i)
{
printf("%d ", a[i]);
}
printf("\n");
}
return 0;
}