Abstract Base Classes
In this lesson, we'll study abstract base classes.
We'll cover the following
Inheritance #
When one class inherits from another class, it gets all its attributes and members from the parent class.
-
During inheritance, the access specifier of the inherited class and the access specifier of the inheritance must be considered.
-
The inherited classes use the attributes and methods from the parent class and can add new ones.
-
Inheritance is the base for polymorphism. One of the three key characteristics of object orientation.
Polymorphism: when the characteristics of an object behave differently at run time.
Abstract base classes #
These are classes that have at least one pure virtual method. By declaring a method virtual and adding = 0
to the method declaration, we can make a method pure virtual.
class Account{
public:
virtual double estimateReturn() = 0;
...
}
Abstract Base Classes are typically used as interfaces for class hierarchies because they determine the implementation of the derived classes.
Rules #
- A class that has a pure virtual method cannot be instantiated.
- A derived class has to implement the pure virtual method in order to get instantiated.
- A pure virtual method can be implemented in a class.
- We must implement a pure virtual destructor. Idiom in C++ is used to declare an abstract base class.
In the next lesson, we’ll study the access rights of inheritance that are available to classes.
Get hands-on with 1200+ tech skills courses.