C code

/*交换a,b的值*/
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
//函数的声明<br/>
int change_1(int a,int b);
int change_2(int *pa,int *pb);
int change_3(int &a,int &b);
int main()
{
  int a,b;
  int *pa,*pb;
  a = 1;
  b = 2;
  pa = &a;
  pb = &b;
  //test1
  change_1(a,b);
  printf("%d%d\n",a,b);
  //test2
  change_2(pa,pb);
  printf("%d%d\n",a,b);
  //test3
  change_3(a,b);
  printf("%d%d\n",a,b);
  return 0;
}
  
int change_1(int a,int b){
  /*值传递*/
  int temp;
  temp = a;
  a = b;
  b = temp;
  return 0;
}
  
int change_2(int *pa,int *pb){
  /*指针传递(值传递的另一种方式)*/
  int *temp;
  temp = pa;
  pa = pb;
  pb = temp;
  return 0;
}

int change_3(int &a,int &b){
  /*址传递*/
  int temp;
  temp = &a;
  &a = &b;
  &b = temp;
  return 0;
  }