[C++-sig] iterators and abstact base class

[Francois Ostiguy]

Hi -

This has to be an FAQ. I searched the list archives and I was not able
locate a satisfactory solution to the following problem:

Assume an abstract base class A and a derived class B. I have an iterator
I for a container C holding B-type objects.  The iterator returns a
pointer to the base class A.
At runtime, I.next() returns a type A which cannot be instantiated.
I would like to iterate through my container and call a (virtual) function
on each element.  Can you point me to an idiom/technique that would
allow me to accomplish this ?

As always, any help is greatly appreciated.

-Francois

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Dr. Jean-Francois OSTIGUY                              voice: (630) 840-2231
Beam Physics Dept MS220                                  FAX: (630) 840-6039
Fermi National Accelerator Laboratory                email: ostiguy at fnal.gov
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