C++计时

• 使用C语言中的 (time.h)
  https://blog.csdn.net/u011391905/article/details/53034200

• OpenCV
  https://github.com/XYZ-qiyh/PlaneFitting/blob/master/src/test.cpp#L23-L26

// 计时原理：t秒内的count数/一秒的count数=代码段运行所需的时间
double t = (double)getTickCount();
// do something ...
t = ((double)getTickCount() - t)/getTickFrequency();  // 单位: seconds

• OpenCV C++计时2
  getTickCount()返回操作系统启动到当前所经过的计时周期
  getTickFrequency()返回每秒的计时周期（即Tick Per Second）

int64_t start = cv::getTickCount();
// type your code here
int64_t end = cv::getTickCount();
double runtime = double(end - start) / double(cv::getTickFrequency()); // 计时单位: μs

getTickCount()函数在core.hpp中定义，返回值类型为int64，占用8个字节。
代码中我们使用了int64_t数据类型，之前出现过这样的情况：计时结果为负，将int改为int64_t后解决了此问题

• Linux C/C++获取程序运行时间
  https://blog.51cto.com/u_15786574/5715356

• Chrono in C++
  https://www.geeksforgeeks.org/chrono-in-c/

参考资料

• https://levelup.gitconnected.com/8-ways-to-measure-execution-time-in-c-c-48634458d0f9