08 const修饰结构体指针形参变量

//结构体类型的定义
struct stu
{
    char name[50];
    int age;
};
void fun1(struct stu * const p)
{
    //p = NULL; //err
    p->age = 10; //ok
}
//void fun2(struct stu const*  p)
void fun2(const struct stu *  p)
{
    p = NULL; //ok
    //p->age = 10; //err
}
void fun3(const struct stu * const p)
{
    //p = NULL; //err
    //p->age = 10; //err
}