c++测试代码块所需时间(windows)

#include <iostream>
#include <windows.h>

using namespace std;

int main()
{
	double run_time = 0.0;		//运行时间
	_LARGE_INTEGER time_start;  //起始时间
	_LARGE_INTEGER time_over;	//结束时间
	_LARGE_INTEGER freq;
	double dqFreq;	//计时器频率

	QueryPerformanceCounter(&freq);
	dqFreq = (double)freq.QuadPart;
	QueryPerformanceCounter(&time_start);
	//测试for循环时间
	for (int i = 0; i < 10000; i++)
	{
	}
	QueryPerformanceCounter(&time_over);
	run_time = 1000 * (time_over.QuadPart - time_start.QuadPart) / dqFreq;
	cout << run_time << "ms" << endl;
	
	getchar();

	return 0;

}