Windows实现精确计时

//
//QueryPerformanceCounter()这个函数返回高精确度性能计数器的当前计数值
//QueryPerformanceFrequency()返回机器内部定时器的时钟频率,每秒嘀哒声的个数.
//两次计数值之差除以时钟频率就是两次的间隔时间，单位是秒
//

#include <iostream>
#include<stdio.h>
#include<Windows.h>

using namespace std;

int main()
{
	LARGE_INTEGER nFreq;
	LARGE_INTEGER nBeginTime;
	LARGE_INTEGER nEndTime;

	QueryPerformanceFrequency(&nFreq);

	QueryPerformanceCounter(&nBeginTime);

	for (int i = 0;i < 1000;++i)
	{
		printf("%d\n",i);
	}

	QueryPerformanceCounter(&nEndTime);

	int continueTime = (double)(nEndTime.QuadPart - nBeginTime.QuadPart)*1000 / nFreq.QuadPart;  //获得对应的时间值，单位为秒

	printf( "time cost is %d ms.", continueTime);
	system("pause");
	return 0;
}