Understanding Static & Dynamic Polymorphism

If you wanna force to any method that will must be override in child class then you Attach, virtual keyword to that method

And in child class attach override keyword with that method and u can override this

If you want to declare basic implementation of method in base class then use virtual keyword and this implementation could be overridden in child class.So, overriding of implementation is optional. If you want to force child class to perform implementation of derived method then use abstract keyword.So, overriding of implementation is compulsory.