函数----交换数值

错误：

#include<stdio.h>
void Swap1 (int x,int y)//形参
{
   int tmp = 0;//定义一个临时变量
   tmp = x;
   x = y;
   y = tmp;
}
int main()
{
  int a = 10;
  int b = 30;
  printf("a=%d , b=%d",a,b);
  Swap1(a,b);//实参
  printf("a=%d , b=%d",a,b);
  return 0;
}

正确：​​

#include<stdio.h>
void Swap2 (int* pa,int* pb)
{
   int tmp = 0;//定义一个临时变量
   tmp = *pa;
   *pa = *pb;
   *pb = tmp;
}
int main()
{
  int a = 10;
  int b = 30;
  printf("a=%d , b=%d",a,b);
  Swap2(&a,&b);//交换a,b;
  printf("a=%d , b=%d",a,b);
  return 0;
}