What are abstract classes in OOP and when are they used?

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Aryan Kumar · Answer

Sure. In object-oriented programming (OOP), an abstract class is a class that cannot be instantiated. This means that it cannot be created as an object. Abstract classes are used to define common behavior or properties that are shared by a set of subclasses.

Abstract classes are used to achieve greater code reuse and flexibility in OOP. By defining common behavior in an abstract class, subclasses can inherit that behavior without having to reimplement it. This can save time and effort, and it can also help to ensure that the behavior is implemented consistently across all subclasses.

Abstract classes can also be used to enforce certain constraints on subclasses. For example, we might have an abstract class called Shape that defines the common behavior of all shapes. This behavior might include methods for calculating the area and perimeter of a shape. We could then have subclasses of Shape that represent specific types of shapes, such as circles, squares, and triangles. These subclasses would inherit the common behavior from the Shape class, but they would also have to implement a method for drawing the shape. This method would be abstract in the Shape class, which would force subclasses to implement it.

Here are some examples of when abstract classes might be used:

A library of mathematical functions: An abstract class could be used to define the common behavior of all mathematical functions, such as addition, subtraction, multiplication, and division. Subclasses of this abstract class could then implement specific implementations of these functions.
A game engine: An abstract class could be used to define the common behavior of all game objects, such as position, velocity, and rotation. Subclasses of this abstract class could then implement specific behavior for different types of game objects, such as characters, enemies, and projectiles.
A web framework: An abstract class could be used to define the common behavior of all web controllers, such as handling requests and generating responses. Subclasses of this abstract class could then implement specific behavior for different types of web controllers, such as REST controllers and SOAP controllers.

Here are some of the benefits of using abstract classes:

Code reuse: Abstract classes allow for greater code reuse by defining common behavior or properties that can be inherited by subclasses.
Flexibility: Abstract classes can be used to enforce certain constraints on subclasses, which can help to ensure that the code is implemented consistently.
Abstraction: Abstract classes can be used to hide implementation details from the user, which can make the code more understandable and maintainable.

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What are abstract classes in OOP and when are they used?

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