C語言交換a,b的方法

#include <stdio.h>
void exchange0(int *a ,int *b)  //通過指針交換兩者的值
{
    int c;
    c = *a; *a = *b; *b= c;
}

void exchange1(int *a,int *b)  //沒有交換兩者的值,只是交換了地址
{
    int *c;
    c = a; a=b; b=c;
}

void exchange2(int &a,int&b)//通過引用交換兩者的值
{
    int c;
    c = a; a= b; b=c;
}

void exchange3(int &a,int &b)//通過異或交換兩者的值
{
    a =a^b;
    b= a^b;
    a = b^a;
}

void main()
{
    int a=3,b=4;
    exchange0(&a,&b);
    printf("%d\t%d\n",a ,b);
    exchange1(&a,&b);
    printf("%d\t%d\n",a ,b);
    exchange2(a,b);
    printf("%d\t%d\n",a ,b);
    exchange3(a,b);
    printf("%d\t%d\n",a ,b);
}