🚀 go-pugleaf

"Alistair" <NoSpamPlease@Somewhere.Com> wrote in message
news:438eb24c$1@newsgroups.borland.com...

> I have another method in my class Base called DoExecute(),
> that calls the Execute method. e.g.
>
> // I WANT THIS FUNCTION IN THE BASE CLASS
> TO CALL THE Execute() IN THE DERIVED CLASS

That is exactly what actually happens when you call a virtual method that
has been overriden.

> Since I have overridden the Execute method in my Derived class,
> shouldn't that call the Execute method in the Derived class?

Usually, yes.  The *only* time that it would not do so is when you call
Execute() in the context of either the constructor or destructor of the Base
class.  In those two specific circumstances, the Derived class does not
exist, so Derived::Execute() cannot be executed.

You have not shown where exactly you are actually calling DoExecute() from.
Please show a full code example that actually compiles.  Otherwise, there is
no way to know for sure why Derived::Execute() is not being called for you.
My guess, based on this discussion so far, would be that you are calling
DoExecute() in the Base class constructor, is that correct?

> Or am I getting this all wrong?  I either get the base method
> called and not the derived or I get a pure function call error.

Since Execute() is a pure abstract method in the Base class, the only way to
get such a runtime error means that the Derived class does not exist at the
time of the call.  Which goes back to the theory that you are calling
DoExecute() from either the constructor or destructor of the Base class.


Gambit