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From: jfw@rome.wpd.sgi.com (john fergus wilkinson)
Newsgroups: comp.lang.c++
Subject: Re: problem with virtual function
Message-ID: <1990Aug21.002654.20506@odin.corp.sgi.com>
Date: 21 Aug 90 00:26:54 GMT
References: <9008201757.AA23899@sirius.risc.com>
Sender: news@odin.corp.sgi.com (Net News)
Reply-To: jfw@rome.wpd.sgi.com (john fergus wilkinson)
Organization: Silicon Graphics, Inc., Mountain View, CA.
Lines: 35

In article <9008201757.AA23899@sirius.risc.com>, ckl@SIRIUS.RISC.COM
(Carl K. Lim) writes:
> 
> Hello.  I have this problem: when I'm calling a virtual function from
a parent
> class's constructor, it fails to execute the derived class's function.  For
> example, in the following program, when B is declared, print() is called from
> A's constructor.  But instead of looking up the B::print(), A::print() is
> called instead.  Has anybody run into this kind of problem?  Is there a way
> to get around it?
> 
> 	#include <stdio.h>
> 
> 	class A
> 	{
> 	public:
> 	  A() { print(); }
> 	  virtual void print() { printf("A\n"); }
> 	};
> 
> 
> 	class B : public A
> 	{
> 	public:
> 	  B() {}
> 	  void print() { printf("B\n"); }
> 	};
> 
> 
> 	int main()
> 	{
> 	  B b;
> 	}

See Ellis and Stroustrup, Section 12.7.