Re: A simple problem with an abstract class...

Norbert Unterberg <nunterberg@newsgroups.nospam>
Thu, 22 Mar 2007 07:49:30 +0100
Jim Brown schrieb:


I'm working an a large legacy app that is built with Makefiles using the
Microsoft Visual Studio 8/VC/BIN/cl.EXE compiler. I have a crazy problem
that I'm hoping someone has seen before. I've included a simplified version
of the problem that runs fine in a VC++ console test project. The project
crashes if I instantiate an object of class B without commenting out the
call to the pure virtual function x() in A::doIt(); Naturally, B deals with
objects derived from A.

Thanks for taking a look.

class A
      void doIt() { x(); }
      virtual void x() = 0;
      virtual ~A() {}

class B

      B() {}
      void push(A* pA) { ... }
      A* pop() { A* pA = ...; return pA; }
      void tryIt() { A* pA = pop(); pA->doIt(); }

I would assume B has to handle some A derived class that did not overload x()
(however that happended). You could verify that by creating a default
implementation of A::x() that ASSERTS or breaks in the debugger.


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