#include<iostream>

#include<stdio.h>

using namespace std;

void ?fun1(int a ,int b )

{

cout<<a<<b;

int c ;

c = a ;

a = b;

b = c;

cout<<a<<b;

}

//引用?

void fun2(int &a, int &b)

{

cout<<a<<b;

int c ;

c = a ;

a = b;

b = c;

cout<<a<<b;

}

//指針?

void fun(int *a ,int *b)

{

cout<< *a<< *b;

int c;

c = *a;

*a = *b;

*b=c;

cout<< *a<< *b;

}

int main(){

? ?int ?x =1 ,y =2;

? ?//fun1(x,y);

? ?//fun2(x,y);

? ?fun(&x,&y);

}