Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!godzilla!kohlrabi!robert
From: robert@kohlrabi.tcs.com (Robert Blumen)
Newsgroups: comp.lang.c++
Subject: Re: Multiple Inheritance Problem
Message-ID: <2153@godzilla.tcs.com>
Date: 6 May 91 19:06:41 GMT
References: <74462@brunix.UUCP>
Sender: root@tcs.com
Reply-To: robert@kohlrabi.tcs.com (Robert Blumen)
Organization: Teknekron Communications Systems
Lines: 39


In article <74462@brunix.UUCP>, thc@cs.brown.edu (Thomas Colthurst) writes:
|> class Object {
|> public:
|>   Object();
|>   ~Object();
|>    virtual void Draw() = 0;
|>    virtual void Update() = 0;
|>    virtual Object* Dup() = 0;
|> }
|> class Line: public virtual Object {
|> public:
|>    Line();
|>    ~Line();
|>    void Draw();
|> }
|> class Dependent: public virtual Object {
|> public:
|>   Dependent();
|>   ~Dependent();
|>   void Update();
|> }
|> class DependentLine : public Line, public Dependent {
|> public:
|>   DependentLine();
|>   ~DependentLine();
|>   Object *Dup() { return( (new DependentLine) ); }; // error here
|> }
|> Sun CC version 2.1 gives me an error on the line
|> marked above, saying
|> "./ChildrenObjs.H", line 30: error: `new' of abstract class DependentLine

For one thing, a class that inherits a pure virtual function must define it
or redefine it to be pure virtual.

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