用c++实现获取程序运行的时间

看代码:

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

     begin = time(NULL);
     cout<<"**************************\n\n\n\n\n\nI love you!\n\n\n\n\n**************************"<<endl;
     i = ;
     while(i++ < ) ;
     end = time(NULL);
     cout << difftime(end, begin) << 's' << endl;
 }