Re: static method returning inherited type

From:

"Fred Zwarts" <F.Zwarts@KVI.nl>

Newsgroups:

comp.lang.c++

Date:

Wed, 21 Jun 2006 12:32:03 +0200

Message-ID:

<e7b5ft$49i$1@info.service.rug.nl>

"Dan" <daniel.doyle@gmail.com> wrote in message =
news:1150884097.396055.57510@m73g2000cwd.googlegroups.com...

I have class B and C which inherit from class A.
I have a static method:

A* aRequest(unsigned char *byte_buffer, size_t length)
{
   A *foo;

   if(something == true)
   {
       foo = new B;
       return foo;
   }
   else
   {
       foo = new C;
       return foo;
   }
}

So that when the method aRequest is called from my parser it should
return a pointer to one of the subclass types B or C.

Problem is when I try to use this:

XMLRequest *foggy;
foggy = A::aRequest(buffer, len);
foggy->someOtherBMethod();

It says the referenced object "someOtherMethod" is not a member of
class A. Can anybody help me out here? I'm not really sure how to do =

properly.

It is not clear what you mean.
Is someOtherBMethod the same as someOtherMethod?
Are these methods of class A, or of class B?
Is XMLRequest the same as A?
Note that you cannot call methods of class B with a pointer to a class A =
object.
If you want to access a method of class B with a pointer to a class A =
object,
you could try to use dynamic_cast to convert the foggy pointer to an =
other pointer
which the points to an object of class B.

Fred.Zwarts.