计算程序运行时间

#include <iostream>  

#include <time.h>

int main(void)   

{  

    int sum = 0;

    time_t t,t1;        time(&t);        //t = time(NULL);

    std::cout<<ctime(&t);        //单位为秒



    int star = clock();                //单位毫秒

    for (int i=1; i <=10000; ++i) 

    {  

        sum = sum+i;

    }  

    std::cout<<sum<<std::endl;

    int stop = clock();

    std::cout<<stop - star<<"毫秒"<<std::endl;

    time(&t1);        

    int t3 = t1-t;

    std::cout<<t3<<" 秒"<<std::endl;

    std::cout<<ctime(&t1);        

    system("pause");

    return 0;  

}