The role of the const

The function of const is to declare a read-only property.

The const function differs in different positions, but still plays a read-only attribute.

int const A;

const int A;

The function is the same, which defines a constant integer type. A is allocated in the static storage area.

const int *a;

int const *A;

The variable to which a is directed cannot be modified.

int b;

int * Const a=&b;

A is read-only and cannot operate on a, that is, a++ is wrong. However, you can modify the variables indicated by a, which must indicate the direction of a at initialization, because you cannot modify the direction of a at a later time.

const INT * Const a=&b;

A is read-only, initialized at the time of declaration, and cannot modify the variable it points to by a, i.e. *a=9;

The role of the const