Re: Polymorphism problem with virtual functions ...

From:
"=?iso-8859-1?q?Erik_Wikstr=F6m?=" <eriwik@student.chalmers.se>
Newsgroups:
comp.lang.c++
Date:
12 Feb 2007 05:11:21 -0800
Message-ID:
<1171285881.535009.132880@m58g2000cwm.googlegroups.com>
On Feb 12, 12:15 pm, Jonas Huckestein <Jonas.Huckest...@web.de> wrote:

Hello,

I have the following problem: I have one BaseClass, which defines the
virtual functions getValue(int index) and virtually overloads the operato=

rs

*, /, -, +. Now I want two classes SubClass1 and SubClass2 which extend t=

he

BaseClass and implement the virtual functions, so that I can go like this:

BaseClass *oskar = new SubClass1;
BaseClass *newton = new SubClass2;
BaseClass *pete = oskar*newton+newton/oskar;


Note that this will not do what you want it to do. This will perform
arithmetic operations with the pointers and not with the objects, you
have to dereference the pointers first:

BaseClass *pete = *oskar * (*newton) + *newton / *oskar;

And unless SubClass + SubClass returns a pointer you should use

BaseClass *pete = new SubClass(*oskar * (*newton) + *newton / *oskar);

It would probably be easier to use references/local variables instead.

--
Erik Wikstr=F6m

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