Tip_卡(qiǎ)时

头文件 time.h

#include<ctime>
#include<cstdio>
int main(){
    int a=0;clock_t cl=clock();
    while(true){
        a=a+1;
        if(clock()-cl>=0.9*CLOCKS_PER_SEC) break;
    }
    printf("a = %d time = %lf\n",a,double(clock()-cl)/CLOCKS_PER_SEC);
    return 0;
}