RE: [Dev-C++] Virtual functions?

[Jaap de W. <wo...@ne...>]

You have access to functions without knowing of which class they are:

eg:
suppose you have a base class Person with virtual function: IsMale();
You have two derived classes: Man and Woman.
std::list<Person *>	Employees;

You can add a man to your organisation by:
Employees.push_back(new Man(...));
or a woman
Employees.push_back(new Woman(...));

Now you can count the number of man in your organisation with 
NrMan = 0;
for (i=Employees.begin(); i != Employees.end(); i++)
{
	NrMan = (*i)->IsMale();
}


> -----Original Message-----
> From: pr...@le... [mailto:pr...@le...]
> Sent: Monday, July 21, 2003 12:04 PM
> To: dev...@li...
> Subject: [Dev-C++] Virtual functions?
> 
> 
> Hi List,
> 
> I've been through numerous books & websites on this topic, 
> but I _still_
> can't quite understand what is the purpose of a virtual function.
> 
> From what I understand, a virtual function is defined in a 
> base class, but
> isn't implemented there. The implementation goes in the 
> derived class. Now
> if this is true, then why should I need to define a function 
> in my base
> class at all? Since I'm eventually going to implement it 
> elsewhere, I might
> as well define it there too.
> 
> Am I even on the right track here? Can someone take me back 
> to base again?
> 
> Thanks.
> 
> Regards,
> Pranav Negandhi
> 
> 
> 
> 
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