Constant pointers and pointer constants in C + +

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  c++11 Use nullptr keyword is a null pointer that expresses a more accurate, type-safe

  Pointer to constant

  • You cannot change the value of a pointed object by a pointer to a constant, but the pointer itself can be changed to point to another object.

  • Cases

  int A;

  const int *p1 = &a; P1 is a pointer to a constant

  int b;

  P1 = &b;//correct,P1the value of itself can be changed

  * P1 = 1;// compile-time error, cannot passP1change the object you are referring to

  Constants for pointer types

  int A;

  int * Const P2 = &a;

  P2 = &b; Error,p2 is a pointer constant, the value cannot be changed

  
  

Constant pointers and pointer constants in C + +