C/C++各种计时函数

对Windows平台下常用的计时函数进行总结，包括精度为秒、毫秒、微秒三种精度的5 种方法。分为在标准C/C++下的二种time()及clock()，标准C/C++所以使用的time()及clock()不仅可以用在Windows 系统，也可以用于Linux系统。

在Windows系统下三种，使用Windows提供的API接口timeGetTime()、 GetTickCount()及QueryPerformanceCounter()来完成。

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#include <windows.h>
#include <time.h> //time_t time() clock_t clock()

#include <Mmsystem.h> //timeGetTime()
#pragma comment(lib, "Winmm.lib") //timeGetTime()

int main(int argc, char*
argv[])

{
//用time()来计时 秒

time_t timeBegin, timeEnd;
timeBegin = time(NULL);

Sleep(800);
timeEnd = time(NULL);

printf("time %d\n", timeEnd - timeBegin);

//用clock()来计时 毫秒

clock_t clockBegin, clockEnd;
clockBegin = clock();

Sleep(800);
clockEnd = clock();

printf("clock %d\n", clockEnd - clockBegin);

//用timeGetTime()来计时 毫秒

DWORD dwBegin, dwEnd;
dwBegin = timeGetTime();

Sleep(800);
dwEnd = timeGetTime();

printf("timeGetTime %d\n", dwEnd - dwBegin);

//用GetTickCount()来计时 毫秒

DWORD dwGTCBegin, dwGTCEnd;
dwGTCBegin = GetTickCount();

Sleep(800);
dwGTCEnd = GetTickCount();

printf("GetTickCount %d\n", dwGTCEnd - dwGTCBegin);

//用QueryPerformanceCounter()来计时 微秒

LARGE_INTEGER large_interger;
double dff;

__int64 c1, c2;
//获取是否支持精确定时器。 定时器的频率

if( QueryPerformanceFrequency(&large_interger) )
{

dff = large_interger.QuadPart;
//获取定时器的值

QueryPerformanceCounter(&large_interger);
c1 = large_interger.QuadPart;

Sleep(800);
//获取定时器的值

QueryPerformanceCounter(&large_interger);
c2 = large_interger.QuadPart;

printf("本机高精度计时器频率%lf\n", dff);
printf("第一次计时器值%I64d 第二次计时器值%I64d 计时器差%I64d\n",
c1, c2, c2 - c1);

printf("计时%lf毫秒\n", (c2 - c1) * 1000 / dff);
printf("\n");

}

return 0;
}