程序代码:

#include <iostream>
#include <Windows.h>
using namespace std;
void main(void)
{
LONGLONG begin_time;
LONGLONG end_time;
double time_fre;
double time_elapsed;
LARGE_INTEGER litmp;

QueryPerformanceFrequency(&litmp);
time_fre = (double)litmp.QuadPart;
QueryPerformanceCounter((LARGE_INTEGER *)&begin_time);
int i = 0; //测试int i = 0及上下语句执行间的时间间隔，秒为单位
QueryPerformanceCounter((LARGE_INTEGER *)&end_time);
time_elapsed = (end_time - begin_time) / time_fre;
cout.precision(20);

cout<<"time elapsed:"<<time_elapsed<<endl;
}