Dynamic versus static polymorphism

When you learn about object-oriented programming, you learn about its fundamental principles, which are abstraction, encapsulation, inheritance, and polymorphism. C++ is a multi-paradigm programming language that supports object-oriented programming too. Although a broader discussion on the principles of object-oriented programming is beyond the scope of this chapter and this book, it is worth discussing at least some aspects related to polymorphism.

So, what is polymorphism? The term is derived from the Greek words for “many forms”. In programming, it’s the ability of objects of different types to be treated as if they were of the same type. The C++ standard actually defines a polymorphic class as follows (see C++20 standard, paragraph 11.7.2, Virtual functions):

A class that declares or inherits a virtual function is called a polymorphic class.

It also defines polymorphic objects based on this definition, as follows...