Re: Why 'delete []' for aray?
On Mon, 11 Feb 2008 13:52:14 -0200, "Cholo Lennon"
<chololennon@hotmail.com> wrote:
In some contexts an array is directly convertible to a pointer to its 1st
element (decay to pointer)
s/some/almost all/
Exceptions: sizeof(array), &array, binding to a reference to an array.
so if you use delete, how can the compiler know if
you want to delete the 1st element or the complete array? It can't. It's for
that reason that Igor told you "...But it doesn't know how many elements are in
the array, or that, in fact, >>> the pointer points to an array <<< ..."
The question isn't quite "delete the first element" (that would be
undefined) vs "delete the array"; it's really "delete a scalar" vs "delete
an array". It would be possible to have only one form of delete, but it
would require treating all allocations the same by storing the number of
elements allocated in the block of memory, probably just before the
complete object. For arrays, this is already done, at least for classes
with destructors. This would obviously be less efficient than having
separate scalar and array delete, which requires an object count *only* for
arrays whose item type has a destructor.
To the OP: Look at the bright side; at least you don't have to say "delete
[n] p", which was originally necessary to delete an array. :)
--
Doug Harrison
Visual C++ MVP