Re: So You Think You Can Const?

David Brown <david.brown@hesbynett.no> writes:
[...]

int v = 123; // Non-const object definition
const int * cp = &v; // Const pointer to non-const data

cp isn't a const pointer, i.e., it's not a pointer object whose value
cannot be changed.  It's a pointer to const, specifically a pointer to
const int.  You could (and arguably should) make the pointer itself
const by defining:

    const int *const cp = &v;

v, as you point out, is a non-const object.  *cp provides access to that
object in a way that forbids changing the target via that pointer.

int * p = (int *) cp; // Cast to non-const pointer
*p = 456; // Change the target data

You could also write:

    *(int*)p = 456;

[...]

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */