Preface ： This article is mainly used for personal review , Pursue simplicity , Thank you for your reference 、 Communication and handling , It may be revised and improved in the future .

Because it's a personal review , There will be partial compression and omission .

The difference between pointer and reference

int main()
{
    int a = 10;

    int& ra = a;// In grammar , Here to a This space has taken an alias , There is no new space 
    ra = 20;

    int* pa = &a;// In grammar , Here's a definition pa Pointer to the variable , opened 4 Byte store a The address of 
    *pa = 20;    


    return 0;
}

Actually, from the perspective of assembly implementation , The underlying layer of the reference is also handled in a similar way to the pointer address

  When using references and pointers , The difference between them ：

1. Reference conceptually defines the alias of a variable , The pointer stores a variable address .

2. Reference redefinition must initialize , Pointer not required .

3. Reference refers to an entity during initialization , You can't refer to other entities , And the pointer can point to any entity of the same type at any time .

4. No, NULL quote , But there are NULL The pointer .

5. stay sizeof Different meanings in ： The reference result is the size of the reference type , But the pointer is always the number of bytes in the address space .

6. Reference self add refers to the addition of referenced entities 1, Pointer self addition means that the pointer is offset backward by a type of size

7. With multi-level pointer , But there is no multi-level reference .

8. Different ways to access entities , The pointer needs to show dereference , References are handled by the compiler itself

9. References are relatively safer to use than pointers