用c++实现获取程序运行的时间

#include<iostream>
#include<ctime>
using namespace std;
int main()
{
time_t begin,end;
begin=clock();
cout<<"**************************\n\n\n\n\n\nI love you!\n\n\n\n\n**************************"<<endl;
end=clock();
cout<<"runtime:"<<double(end-begin)/CLOCKS_PER_SEC<<"s"<<endl;
}