C++计时器：毫秒级和微秒级

1、毫秒级

1. 使用GetTickCount()获取系统启动所经过的毫秒数

#include<iostream>

using namespace std;

int main(){

    DWORD start= ::GetTickCount(); //获取毫秒级数目

    Sleep();

    cout << ::GetTickCount() - start<< endl;

    system("pause");

}

　　 2. 使用clock()

#include <iostream>

#include <time.h>

#include <Windows.h>

using namespace std;

int main(){

    clock_t start;

    start = clock();

    Sleep();

    cout<<clock()-start<<" ms"<<endl;

    system("pause");

}

2、微秒级

1. 先用QueryPerformanceFrequency()获取时钟周期再调用QueryPerformanceCounter()获取CPU从开机以来执行的时钟周期数

#include <stdio.h>

#include <math.h>

#include <windows.h>

using namespace std;

void main()

{

    LARGE_INTEGER cpuFreq;

    LARGE_INTEGER startTime;

    LARGE_INTEGER endTime;

    double rumTime=0.0;

    QueryPerformanceFrequency(&cpuFreq);

    QueryPerformanceCounter(&startTime);

    Sleep();

    QueryPerformanceCounter(&endTime);

    rumTime = (((endTime.QuadPart - startTime.QuadPart) * 1000.0f) / cpuFreq.QuadPart);

    cout << rumtTime << " ms" << endl;

}