C++之时间统计

1.最精确

QueryPerformanceFrequency(&nFreq);

cout <<nFreq.QuadPart<<endl;//获得计数频率

QueryPerformanceCounter(&s);//获取当前计数次数
QueryPerformanceCounter(&e);//获取当前计数次数
float tt = e.QuadPart - s.QuadPart;

2.

<windows.h>的DWORD GetTickCount(void);返回（retrieve）从操作系统启动所经过（elapsed）的毫秒数

int TimeStart=GetTickCount();

int TimeEnd=GetTickCount();

3.

time_t stime , etime ;//time_t = long

time( &stime );

time( &etime );

4.

double begin=(double)clock();

double end=(double)clock();