Re: derived class and virtual function
On 08/13/10 09:36 PM, Francesco S. Carta wrote:
Stuart Redmann <DerTopper@web.de>, on 13/08/2010 02:30:45, wrote:
Stefan van Kessel on 13/08/2010 wrote:
#include<iostream>
class Foo
{
public:
virtual Foo* createCopy(){ return new Foo(*this); }
virtual void quack() { std::cout<<"I'm a foo"<<std::endl; }
virtual ~Foo(){}
};
class Bar : public Foo
{
public:
// notice that this createCopy returns a Bar* instead of Foo*
// which is a "pointer to a class that is PUBLICLY derived"
virtual Bar* createCopy(){ return new Bar(*this); }
virtual void quack() { std::cout<<"I'm a bar"<<std::endl; }
};
int main() {
Bar bar;
Foo& br = bar;
Foo* bp = br.createCopy();
bp->quack();
delete bp;
}
Francesco S. Carta wrote:
Ah, this makes more sense than my example, but I've been able to make it
work even declaring Bar::createCopy() as non-virtual, just for the
records.
A question pops up: How exactly did you manage to make Bar::createCopy
non-virtual? AFAIK, C++ does not allow this.
I've just copied Stefan's code, pasted it into my editor, deleted the
two "virtual" from createCopy() and quack() within class Bar and
compiled it with MinGW 4.4.0.
So the function are still virtual. The virtual keyword in the derived
class is superfluous.
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