abstract method use vs regular methods

Question

I would like to know the difference between two conventions:

1. Creating an abstract base class with an abstract method which will be implemented later on the der

Answer 1

An abstract function can have no functionality. You're basically saying, any child class MUST give their own version of this method, however it's too general to even try to implement in the parent class. A virtual function, is basically saying look, here's the functionality that may or may not be good enough for the child class. So if it is good enough, use this method, if not, then override me, and provide your own functionality...

And of course, if you override a virtual method, you can always refer to the parent method by calling base.myVirtualMethod()