指针*p 二级指针**p 指针引用*&p

#include<iostream>
static int s_num=10;
void fun(int** p){
    std::cout << *p << std::endl;
    std::cout << **p << std::endl;
    *p = &s_num;
}

void fun(int* &p){
	std::cout << *p << std::endl;
    p = &s_num;
}


int main(){
    int num=5;
    int *p = &num;
    std::cout << &p << std::endl;
    std::cout << p << std::endl;
    std::cout << *p << std::endl;
    fun(&p);
    std::cout << p << std::endl;
    std::cout << *p << std::endl;
    p = &num;
    std::cout << p << std::endl;
    std::cout << *p << std::endl;
    fun(p);
    std::cout << p << std::endl;
    std::cout << *p << std::endl;
    return 0;
}

0x61fe40
0x61fe4c
5
0x61fe4c
5
0x403010
10
0x61fe4c
5
5
0x403010
10