Not necessarily. std::function for example provides polymorphism of callables without inheritance. Type erasure can generally used for polymoprhism in C++. Al

Not necessarily. std::function for example provides polymorphism of callables without inheritance. Type erasure can generally used for polymoprhism in C++. Also templates are of course polymorphic and do not require inheritance, but that's not runtime polymorphism which I guess was implied. edit: s/is/can be/