Re: Base Class pointers to Derived Classes calling functions.

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Tue, 1 Jan 2008 03:15:51 -0800 (PST)

Message-ID:

<296494c5-ddd1-47f3-9bd1-ded551a5e804@i3g2000hsf.googlegroups.com>

On Dec 31 2007, 5:20 pm, Ron Natalie <r...@spamcop.net> wrote:

Rahul wrote:

On Dec 31, 7:05 pm, Ron Natalie <r...@spamcop.net> wrote:

Rahul wrote:

dynamic_cast would work only with classes having virtual functions,
typeid operator would
be more appropriate...

typeid has the same restrictions. If the class isn't polymorphic
(virtual) functions, the runtime typing info ain't there.

I meant the compilation error, one gets with dynamic_cast for the
following cases,

ptr1 = dynamic_cast<B*>(ptr2); // gives a compilation
error

If your compiler gives a compilation error there it is
seriously busted. Dynamic cast has a whole slew of cases that
apply EVEN if the classes aren't polymorphic.

True, but pointer to base to pointer to derived isn't one of
them. The above code should result in a compiler error.
(Remember that ptr2 has type A*, and that A is a base class of
B.)

The reverse, of course, should work.

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