C++引用和指针

引用

我们这里说的引用是左值引用(lreference)，在C++中还有右值引用(C++11)

int age = 29;
int &_Age = age;
int &_as; //报错，引用必须要初始化
cout << _Age<<endl;

引用和赋值的区别

int age = 29;
int& _Age = age;

cout << age<<" " << _Age << endl;
_Age = 4;
cout << age << " " << _Age  << endl;



int age1 = 29;
int test1 = age1;

cout << age1 << " "<< test1 << endl;
test1 = 4;
cout << age1  << " " << test1 << endl;

指针

1、指针本身就是一个对象，允许对指针赋值和拷贝

2、指针无须在定义时赋值

int* p1 = nullptr;
int age = 35;
int age1 = 5;

int* p = &age;
int* p2 = p;
cout << *p << endl;

指向指针的指针

int age = 35;
int* p = &age;
int** p3 = &p;

指向指针的引用

int i = 42;
int* p;
int*& r = p;
r = &i;

cout << *r << endl;
*r = 0;
cout << i << endl;