c++基础(引用和指针)

int a = 10;
int b = 1, c = 2;
int &d = a;  //&引用 一定要初始化 且不可更改 只是相当于给变量的别名
int const e = 3;
int const& f = e; //&引用常量
std::cout << "d = " << &d << "  " << "a = " << &a << "\n";    //引用的地址和变量的存储地址是一样的
    //++a = 9; //++a 是可修改的左值

int const *pa = &c;     //常量指针，可改变p1的地址（指向），不可改变*p1的值
pa = &a;
int* const pb = &b;    //指针常量，可改变*p2的值，不可改变p2的地址（指向）
*pb = -1;
std::cout << "a = " << *pa << "  " << "b = " << *pb << "\n";
std::cout << "a = " << pa << "  " << "b = " << pb << "\n";  //指针内存的是地址

int const **p = &pa;  //多级指针 p指向pa
std::cout << "a = "<< **p <<"\n";