Answer 1

A constant pointer is, like any other constant variable, is used to store constants. But since a pointer stores the address, the constant pointer stores a constant address.

Thus, though the value of a constant pointer is modifiable, the address must remain the same.

Eg -

int var = 60;
int* pv = &var;
//Assume &var = 0x12FFD.
int const* cpv = &var;
// Constant pointer - cpv.
var++; // No error.
cout<<*cpv; // Prints 61.
pv++; // Valid operation. pv = 0x12FFE.
cpv++;
// Error. Moving to different address.
// cpv must stay at 0x12FFD.

Note that 'int const*' is different from const int*, as the first is a constant pointer but the second is a pointer pointing to a constant variable, and can have a change in address and not a value.