用C++中的引用和指针分别实现swap函数

#include<iostream>
using namespace::std;
void swap1(int a,int b);
void swap2(int *a,int *b);//调用时实参为变量的地址即指针
void swap3(int &a,int &b);//调用时实参为变量本身，形参是变量的别名即引用
int main()
{
  int a=3;
  int b=5;
  int x=3;
  int y=5;

  swap1(a,b);
  cout<<"out swap1 funtion a="<<a<<endl;
  cout<<"out swap1 funtion b="<<b<<endl;

  cout<<"out swap2 the address of x="<<&x<<endl;

  swap2(&x,&y);
  cout<<"out swap2 funtion x="<<x<<endl;
  cout<<"out swap2 funtion y="<<y<<endl;

  int m=3;
  int n=5;
  swap3(m,n);
  cout<<"out swap3 funtion m="<<x<<endl;
  cout<<"out swap3 funtion n="<<y<<endl;

 return 0;
}

void swap1(int a,int b)
{
  int temp=a;
  a=b;
  b=temp;
  cout<<"in swap1 funtion a="<<a<<endl;
  cout<<"in swap1 funtion b="<<b<<endl;
}

void swap2(int *a,int *b)
{
  int temp=