【测速】memcpy()对比for循环逐个对象拷贝

[color=red][size=x-large]结论：[/size][/color][size=large]一般情况下，memcpy()函数比for循环快个一两倍，某些特殊值上稍微慢点儿。[/size]

[color=red][size=x-large]注意：[/size][/color][size=large]对于需要构造函数、析构函数的类，可能要在拷贝时重载=运算符，此时memcpy()的结果就不是自己想要的了，一般情况下还是老老实实用for循环吧[/size]

[color=red][size=x-large]测试结果如下：[/size][/color]

[img]http://dl.iteye.com/upload/attachment/0076/7247/72a8b802-9e0f-3250-865f-1382aeb40acb.png[/img]

[img]http://dl.iteye.com/upload/attachment/0076/7249/56277b42-e09e-3428-aaa4-7c1134982201.png[/img]

[img]http://dl.iteye.com/upload/attachment/0076/7251/e7eb916a-c74c-3dbd-ad80-27a3267bf17c.png[/img]

[img]http://dl.iteye.com/upload/attachment/0076/7253/7d40e60c-b2f0-31cc-9321-15c2bf2ce0b4.png[/img]

[color=red][size=x-large]测试代码如下（不完全）：[/size][/color]

#include 
#include "..\Include\lc\utility\Timer.hpp"
#include 

using namespace LC;
void main() {
    typedef long long worktype;
    //typedef int worktype;

    for(int num=10; num<10000000; num*=5) {
        const int testNum=10000000/num*100;
        worktype* pDst=new worktype[num];
        worktype* pSrc=new worktype[num];

        Timer timer;
        for (int i=0; i            memcpy(pDst,pSrc,sizeof(worktype) * num	);
        }
        long tMemcpy=timer.getElapsedTimeAndRestart();

        for (int i=0; i            for (int n=0; n                pDst[n]=pSrc[n];
            }
        }
        long timeCopy=timer.getElapsedTimeAndRestart();

        std::cout<<"数组长度："<    }
}