OOPS: how to enforce that a function is implemented in derived class

SystemVerilog
,
5

In reply to dave_59:

In reply to verif_learner:
A class with a pure virtual method needs to be marked as virtual since you cannot be allowed to construct a class with a pure virtual method.

So, what is the point of marking a class virtual, when it has a pure virtual function?
Is it just for readability?

Is the following understanding correct?

  1. a virtual class can have non virtual functions. this class cannot be instantiated
    But one can simply derive from this class and instantiate the derived class without any issues
  2. a class with pure virtual function has to be declared as virtual as well
    In this case, the derived class has to override the pure virtual functions and implement them, without which the derived class becomes virtual as well
  3. so, effectively, one can have hierarchy of virtual classes, each progressively implementing pure virtual functions