Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!taumet!steve
From: steve@taumet.com (Stephen Clamage)
Newsgroups: comp.lang.c++
Subject: Re: Simple example results
Message-ID: <604@taumet.com>
Date: 15 Feb 91 16:43:11 GMT
References: <1991Feb14.165716.14417@cc.ic.ac.uk>
Organization: Taumetric Corporation, San Diego
Lines: 27

rb@cc.ic.ac.uk (Robin Becker) writes:

>Someone posted the following simple inheritance example recently
>here are the results from TC++ and Zortech 2.1

>class derived : public base
>{
>public: 
>/*	virtual void whatami() { printf("I'm a derived.\n"); } */
>	derived() { printf("In the derived constructor "); whatami(); }
>	~derived() { printf("In the derived destructor "); whatami(); }
>};

Since whatami is commented-out in class derived, there is no way to
print the phrase "I'm a derived".

Within the constructor or destructor for any class, virtual function calls
can refer only to functions in the current or base classes, never to 
functions in any derived class.  (In a constructor, the derived class
doesn't exist yet, so you can't refer to its members.  In a destructor,
the derived class is gone, so you can't refer to its members.)

For the code you show, Borland got it right, Zortech is wrong.

-- 

Steve Clamage, TauMetric Corp, steve@taumet.com