Vc如何精确查询代码执行时间

    _int64   Frequency;  
    static _int64   lastTime = 0;  
    _int64   curTime;  
    double dTime = 0;  

    QueryPerformanceFrequency((LARGE_INTEGER   *)   &Frequency);  
    QueryPerformanceCounter((LARGE_INTEGER*)   &lastTime);

    //你的代码

    QueryPerformanceCounter((LARGE_INTEGER*)   &curTime);

    if(lastTime > 0 && curTime > 0 )
    {
        dTime = (double)(curTime - lastTime) / (double)Frequency;
    }