Abstract base class question

[jwjohnwright]

Totally dumb question, I know, but....

What determines whether or not a method must be overridden when deriving from an abstract base class?

class ABC
{
virtual void PrintFunc() = 0;
};

Now if I derive a class from ABC why must PrintFunc() be redefined for the new derived class?

What if the ABC class had something else I wanted but I did not need this particular method in the derived class?

Would I still need to include a definition for PrintFunc() in the derived class?

[firedraco]

A virtual = 0 function is basically like an interface, saying "classes that inherit from this will have this method, but I don't have enough information to give you anything but the definition"

Yes, you would, otherwise the new class is also abstract (and thus cannot be instantiated).

[jwjohnwright]

Thank you! This is exactly what I needed. I am trying to learn the ins and outs of an event system setup, but could not remember why certain function in an ABC must be re-defined in derived classes.