Windows下较为精确的计时方法

头文件

#include <Windows.h>

嵌入到代码中的计时语句

//timer   
2  LARGE_INTEGER    nStartCounter, nStopCounter;   
3 QueryPerformanceCounter(&nStartCounter);//timer starts
4  //【需要计时的代码片段】
5  QueryPerformanceCounter(&nStopCounter);//timer ends   
6  double nTime1 = getCostTime(nStartCounter, nStopCounter);

转换为标准单位second

double getCostTime(LARGE_INTEGER start, LARGE_INTEGER end)
2 {
3     double timeAccuracy = TIME_ACCURACY;
4     LARGE_INTEGER nFrequency;   
5     QueryPerformanceFrequency(&nFrequency);  
6     double time = (double)timeAccuracy * (end.QuadPart - start.QuadPart) / nFrequency.QuadPart;   
7     return time / timeAccuracy;
8 }

时间精度说明

据考证是最精确的计时方法。

（Any doubt? STFW.）