程序代码：

#include <stdio.h>     
void  fun(int *&x)
{
    int b=6666;
    x=&b;
    printf("xxxxxxxxxxxxxxxxx%p\n",x);
    printf("xxxxxxxxxxxxxxxxx%d\n",*x);
}
/*int *fun3()
{
    int v=6666;
    int *x=&v;
    printf("xxxxxxxxxxxxxxxxx%p\n",x);
    printf("xxxxxxxxxxxxxxxxx%d\n",*x);
    return x;
}*/
int main()
{
    int *p=NULL;
    printf("原p存放地址：%p\n",p);
    fun(p);
    if(p==NULL)
        printf("NO DATA!\n");
    else
    {
        printf("后p存放地址：%p\n",p);
        printf("%d\n",*p);
    }
    return 0;
}

程序代码：

#include <stdio.h>    
void  fun(int *&x)//这是有错的，至少我的编译器是过不了的，应为*x
{
    int b=6666;
    x=&b;//x在函数调用时传过来的傎是p所指地址，这里被赋于b的地址，下面输出的是b的地址和b的值
    printf("xxxxxxxxxxxxxxxxx%p\n",x);
    printf("xxxxxxxxxxxxxxxxx%d\n",*x);
}
/*int *fun3()
{
    int v=6666;
    int *x=&v;
    printf("xxxxxxxxxxxxxxxxx%p\n",x);
    printf("xxxxxxxxxxxxxxxxx%d\n",*x);
    return x;
}*/
int main()
{
    int *p=NULL;
    printf("原p存放地址：%p\n",p);
    fun(p);//这里并没有改变p，p仍然是NULL
    if(p==NULL)
        printf("NO DATA!\n");
    else
    {
        printf("后p存放地址：%p\n",p);
        printf("%d\n",*p);
    }
    return 0;
}

程序代码：

#include <stdio.h>
int *  fun()
{
    int b=6666;
    int *a=&b;
    return a;
}
int main()
{
    int *a=fun();
    printf("%d",*a);
    return 0;
}

程序代码：

#include <stdio.h>    
int *  fun(int *&x)
{
    int b=6666;
    x=&b;
    printf("xxxxxxxxxxxxxxxxx%p\n",x);
    printf("xxxxxxxxxxxxxxxxx%d\n",*x);
    return &b;
}
/*int *fun3()
{
    int v=6666;
    int *x=&v;
    printf("xxxxxxxxxxxxxxxxx%p\n",x);
    printf("xxxxxxxxxxxxxxxxx%d\n",*x);
    return x;
}*/
int main()
{
    int *p=NULL,*p1;
    printf("原p存放地址：%p\n",p);
    p1=fun(p);
    if(p==NULL)
        printf("NO DATA!\n");
    else
    {
        printf("后p存放地址：%p\n",p);
        printf("%d\n",*p);
    }
    printf("后p1存放地址：%p\n",p1);
        printf("%d\n",*p1);
    return 0;
}