几种交换方式与参数传递方式效率的比较,发现STL最慢

/*Copyright (c) 2007,九天雁翎

* All rights reserved.

* 几种交换方式与参数传递方式效率的比较

* 完成日期：2007年7月7日*/

#include "stdafx.h"
#include "myself.h"
#include <iostream>
#include <utility>

using namespace std;

const int RUNTIME = 1e5;

void swap1(int &v1, int &v2);
void swap2(int &v1, int &v2);
void swap3(int *p1, int *p2);

int main()
{
    int v1 = 10000;
    int v2 = 20000;
    double t1 = myself::getTime();
    for (int i = 0; i < RUNTIME; ++i)
    {
       swap1(v1,v2);
    }
    double t2 = myself::getTime() - t1;
    cout <<v1 <<'/t' <<v2 <<endl;
    cout <<"Reference pass parameter and bit^ way used time: "<<t2 <<endl;

    t1 = myself::getTime();
    for (int i = 0; i < RUNTIME; ++i)
    {
       swap2(v1,v2);
    }
    t2 = myself::getTime() - t1;
    cout <<v1 <<'/t' <<v2 <<endl;
    cout <<"Reference pass parameter way used time: "<<t2 <<endl;

    t1 = myself::getTime();
    for (int i = 0; i < RUNTIME; ++i)
    {
       swap3(&v1,&v2);
    }
    t2 = myself::getTime() - t1;
    cout <<v1 <<'/t' <<v2 <<endl;
    cout <<"Point pass parameter way used time:" <<t2 <<endl;

    for (int i = 0; i < RUNTIME; ++i)
    {
       swap(v1,v2);
    }
    t2 = myself::getTime() - t1;
    cout <<v1 <<'/t' <<v2 <<endl;
    cout <<"STL way used time: " <<t2 <<endl;

    return 0;
}

void swap1(int &v1, int &v2)
{
    v1 = v1^v2;
    v2 = v1^v2;
    v1 = v1^v2;
}

void swap2(int &v1, int &v2)
{
    int temp = v1;
    v1 = v2;
    v2 = temp;
}

void swap3(int *p1, int *p2)
{
    int temp = *p1;
    *p1 = *p2;
    *p2 = temp;
}