abstract and virtual member functions?

Virtual methods allow subclasses to provide their own implementation of that method using the override keyword.

Abstract methods in a class contain no method body, and are implicitly virtual.

Neither abstract or virtual can be declared private, since it would defeat the purpose, and subclasses must override them using the same method signature.

If a class has any abstact methods, then it must tag itself as abstract, and no instances of it can be created.