Re: Casting from a virtual base class to a parent in a diamond inheritance?

From:

uglystone <zhaojunm@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Tue, 15 May 2007 13:57:14 CST

Message-ID:

<1179205337.619709.3800@n59g2000hsh.googlegroups.com>

On May 15, 8:41 am, linda...@hotmail.com wrote:

     class a {};
     class b : public a {};
     class c : public a {};
     class d : public virtual b, public virtual c {};

     a * ptr = 0;
     d * ptr2 = static_cast<d *>(ptr);
     d * ptr3 = static_cast<d *>(static_cast<b *>(ptr));

If I have a pointer to class a, how do I turn that into a pointer to
class d? I get an ambiguity error for the ptr2 conversion, and I get
an implied error for the ptr3 conversion. Compiler is MSVC++ 8.0.5.

Thanks!

class a {};
class b : public a {};
class c : public a {};
class d : public virtual b, public virtual c {};
The structure seems not to be a diamond inheritance.
It may be look like:
class a {};
class b : virtual public a {};
class c : virtual public a {};
class d : public virtual b, public c {};
do you mean?

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