指针传参

#include "stdio.h"
int b;
void pointer(int* p)　　　　//p指向的是b的地址
{
  int a = 11;
  printf("\n\nEnter function");
  printf("\nthe p is point to  %p , addr is %X, *p is %d\n",p , &p, *p);
  *p =11;　　　　//将p所指向的地址内的值改为11，即b改为11，p的地址没有发生改变，最好用这种方法返回参数
  printf("b: %d\n",b);
  printf("\nthe p is point to  %p , addr is %X, *p is %d\n",p , &p, *p);
  p = &a;　　　　//p指向a，此时p的地址发生改变
  printf("b: %d\n",b);
  printf("\nthe p is point to  %p , addr is %X, *p is %d",p , &p, *p);

  printf("\nfunction return\n");
}

int main()
{
 b =22;
 int *p = &b;

 printf("the b address %X\n",&b);
 printf("the p is point to %p , addr is %X, *p is %d",p , &p, *p);
 pointer(p);　
 printf("\nthe p is  point to %p , addr is %X, *p is %d\n",p , &p, *p);
}