常用的三种获取程序运行时间的方法

• chrono
  参考教程：http://www.cnblogs.com/jwk000/p/3560086.html

#include <chrono>    //C++11chrono::steady_clock::time_point t1 = chrono::steady_clock::now();domeSomething();chrono::steady_clock::time_point t2 = chrono::steady_clock::now();chrono::duration<double> time_used = chrono::duration_cast<chrono::duration<double>>(t2 - t1);cout<<"solve time cost = "<<time_used.count()<<" secondes."<<endl；

• ctime

#include <ctime>using namespace std;clock_t start = clock();// do something...clock_t end   = clock();cout << "花费了" << (double)(end - start) / CLOCKS_PER_SEC << "秒" << endl;//此方法测出来的时间经常不准，不建议使用

• gettimeofday

#include <time.h>using namespace std;timeval start, end;gettimeofday(&start, NULL);// do somethindgettimeofday(&end, NULL);cout << "花费了" << end.tv_sec - start.tv_sec << " s." << endl;cout << "花费了" << end.tv_usec - start.tv_usec << " us." << endl;