C指針，&，*，指針的指針

C指針: 指向變量的地址，想象成房間號

      &: 取地址符號

      *：間接訪問符號, 訪問p所存地址的內容

#include <iostream>

int main(int argc, const char * argv[]) {

    int m = 5;
    int *p = &m;
    
    std::cout << "p = " << p << std::endl; //0x7ffeefbff5bc
    std::cout << "*p = " << *p << std::endl; //5
    
    return 0;
}

#include <iostream>

int main(int argc, const char * argv[]) {

    int m = 5;
    int *p = &m;
    
    std::cout << "p = " << p << std::endl; //0x7ffeefbff5bc
    std::cout << "*p = " << *p << std::endl; //5
    
    std::cout << "&p = " << &p << std::endl;//0x7ffeefbff5a0
    
    int **pp = &p; //& 不可以使用兩次
    
    int b = **pp;
    std::cout << "b = " << b << std::endl; //5
    std::cout << "*pp = " << *pp << std::endl;//0x7ffeefbff58c
    std::cout << "pp = " << pp << std::endl;//0x7ffeefbff570
    return 0;
}

另外注意指針要初始化，否則成為野指針。

參考 https://www.cnblogs.com/mymindview/p/5247485.html