Difference b/w int const * and const int *

[deep725]

please will yu help me to understand the difference b/w int const*p and
const int *p and why do we use them means what are the significance of these ??

[Ejaz]

int const * <--- const pointer

const int * <-- pointer to const

[Danny]

without boring you with a long lecture on the types of const, there's a simple rule: if the const appears after the *, as in

int * const p;

Then the pointer is const, whereas the object to which it points isn't const. If the const appears before the *, either as

const int * p;

or

int const * p;

Then the object is const, whereas the pointer isn't.

Const pointers are rather rare, although they have some valid uses. pointers to const objects are much more common and are used in several ways such as passing read only arguments to a function, ensuring that a C-string isn't altered etc.