C语言——qsort排序

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 100000

void sort_begin(int a[]){
int i;
srand(time(NULL));
for (i = 0; i < N; ++i){
a[i] = rand() % 100;
}
}

int compare(const int* left, const int *right){
if (*left>*right)
return 1;
else if (*left == *right)
return 0;
else
return -1;
}

int main(){
int a
;
int t1,t2;
sort_begin(a);
t1 = clock();
qsort(a, N, sizeof(int), compare);
t2 = clock();
printf("the clock is %d\n", t2 - t1);

system("pause");
return 0;
}