C + + Learning---pointer correlation

1. Pointer to pointer object

General pointers

int *p1,ival = 42;

P1 = &ival;

Or

int ival =42,*p1=&val;

Represents a pointer object pointing to an address area of the same type, if you want to get the value with a parser *

*P1//P1 stores a memory address, * symbol resolves the address until the value 42

Pointer to pointer object

is a pointer to an int object, and now the object is a pointer object.

int i = 42,*P1,**P2;

P1 = &i;

P2 = &p1;

Need to use * * for a reason

2. Pointers to constants and constant pointers

Point to constant type

const int ival = 42;

const int *P1 = &ival;

Constant pointer

int ival = 42;

int *const P1 = &ival;//p1 will always point to ival

C + + Learning---pointer correlation