UML abstract class

An abstract class is a class that is designed to be specifically used as a base class . An abstract class contains at least one pure virtual function. You declare a pure virtual function by using a pure specifier ( = 0 ) in the declaration of a virtual member function in the class declaration.

Abstract classes are essential to providing an abstraction to the code to make it reusable and extendable. For example, a Vehicle parent class with Truck and Motorbike inheriting from it is an abstraction that easily allows more vehicles to be added .

An abstract class is a class that is declared abstract —it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed.

One of the fundamental concepts in OOP is the abstract class. Abstract classes cannot be instantiated and are designed to be subclassed. They are used to provide some common functionality across a set of related classes while also allowing default method implementations .