C ++ Learning (1), Learning

C ++ Learning (1), Learning

C ++ Learning (1)

1. const c vs c ++:

In c, const is a read-only variable (ReadOnly Varible). In c ++, const only represents a Constant (Constant ).

Example:

Const int n = 10;

Int arry [10] // OK in c ++ error in c.

2. Two attributes of the pointer:

(1). pointer itself;

(2) Data pointed to by the pointer;

3. Constant pointers and pointer constants:

(1 ).Constant pointer(Point to constant or constant point ):

Concept: pointer to a constant;

Definition: const int * p;

Example:

Const int * p1;

Const int x = 1;

P1 = & x; // correct

* P1 = 10; // Error

Here, a constant refers to a constant for the solution reference;

(2 ).Pointer constant(Point constant)

Concept: an immutable Pointer Points to a variable value;

Definition: int * const p;

Example:

Const int x = 1

Int * const p1 = & x; // super important step. Be sure to write to whom p1 points.

* P1 = x // or y. You can leave it empty. If you leave it empty, it indicates the value of the variable pointed to by p1;

P1 = & y // incorrect, because the pointer in the pointer constant cannot be changed.

# The array name is a pointer constant !!