除法,乘法,移位耗时对比

#除法,乘法,移位耗时对比
发现移位和乘法比除法要省3-5倍时间,移位相对而言是最省时间的

    auto time_start = std::chrono::system_clock::now();
    int n = 100000;
    double d ;
    for (int i = 0; i < 1000000; i++)
    {
         d = n / 2;
    }
    std::chrono::duration<double> time_spend = std::chrono::system_clock::now() - time_start;
    double time_cost = time_spend.count() * 1000;
    cout<<"div cost "<<time_cost<<" ms"<<endl;

    time_start = std::chrono::system_clock::now() ;
    for (int i = 0; i < 1000000; i++)
    {
         d = n * 0.5f;
    }
    time_spend = std::chrono::system_clock::now() - time_start;
    time_cost = time_spend.count() * 1000;
    cout<<"muutiple cost "<<time_cost<<" ms"<<endl;

    time_start = std::chrono::system_clock::now() ;
    for (int i = 0; i < 1000000; i++)
    {
         d = n >>1;
    }
    time_spend = std::chrono::system_clock::now() - time_start;
    time_cost = time_spend.count() * 1000;
    cout<<"shit cost "<<time_cost<<" ms"<<endl;
    return 0;

输出结果如下:
div cost 0.000139 ms
muutiple cost 3.3e-05 ms
shit cost 2.8e-05 ms

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原文：https://blog.csdn.net/weixin_40024157/article/details/82898627