C + + Learning Note (4) const qualifier

One, the const object is only valid within the file by default, and can be accessed using the Extern keyword setting for all files.

Second, a reference to a constant: const int CI = 1024x768; const int &r = CI;

Temporary volume (Temporary volume object): An unnamed object that is temporarily created when the compiler needs a space to hold the evaluation result of an expression;

Iv. Pointers to constants:

1, const double A = 0.6; const double *P = &a;

2, double b = 0.5; Const double *P2 = &b;

Note: A constant pointer can point to a very constant object, but a very pointer cannot point to a const object;

Five, constant pointer:

Const double A = 0.8;

Const double *const pi = &a;

The top-level const means that the pointer itself is a constant, the underlying const means that the pointer refers to the object is a constant, the const declaration reference is the underlying const;

C + + Learning Note (4) const qualifier