class hirachy problem

[John Love-Jensen]

Hi Kristian,

I'd make fun2 a virtual method in the CAlpha, to avoid the need to do what
you are doing.

But I understand that this is a simplified example to express the concept,
and not a particular situation, so my initial response may not be relevant.

To me there is no difference between using dynamic casts, and using the
pixelTypes technique.  Both suffer from lack-of-encapsulation.

Sincerely,
--Eljay