virtual function

[asdf]

The derived class can redefine the virtual function in the base class.
So, the derived class can redefine the return type, the parameters
list, and the whole content of the virtual function. The derived class
only need to keep the name of the virtual function.

Is this right? Thanks.

 

[Bart]

The derived class can redefine the virtual function in the base class.

The derived class *overrides* the base class implementation.

So, the derived class can redefine the return type, the parameters
list, and the whole content of the virtual function.

No. If you change the parameters you will hide the base class
implementation. That's not the same as overriding.

Regards,
Bart.

 

[Nate Barney]

The derived class can redefine the virtual function in the base class.

A derived class can *override* a virtual function in a base class.

So, the derived class can redefine the return type,the parameters
list, and the whole content of the virtual function. The derived class
only need to keep the name of the virtual function.

Is this right? Thanks.

No. The function signature must remain the same in both classes. This
includes whether the function is declared const. The one exception is
that an overridden virtual function may have a different return type,
but only a type derived from the original return type.

Nate

 

[Nate Barney]

The one exception is that an overridden virtual function may have a
different return type, but only a type derived from the original
return type.

Actually, this is only true for references and pointers to the
aforementioned types. For more information on this, google for
"covariant virtual function".

Nate