4 Key Concepts of Object-Oriented Programming (OOP)

Encapsulation

Definition: Bundling of data (attributes) and methods (behavior) into a single unit (class).

Purpose: Protects data from unauthorized access and modification, promotes code reusability, and improves maintainability.

Example: A Person class with attributes like name, age, and methods like getName(), setAge().

Inheritance

Definition: Establishing a hierarchical relationship between classes, where one class (subclass or child class) inherits properties and behaviors from another class (superclass or parent class).

Purpose: Promotes code reuse, creates a clear class hierarchy, and enables polymorphism.

Example: A Dog class inheriting from an Animal class, inheriting common properties like name and methods like makeSound().

Polymorphism

Definition: The ability of objects of different classes to respond to the same method call in different ways.

Purpose: Enables flexible and dynamic code, promotes code reusability, and makes code more adaptable to changes.

Types:

• Method overriding: When a subclass provides a different implementation of a method inherited from the superclass. It uses dynamic binding and can be checked at run time.

• Method overloading: when a class has multiple methods with the same name but different parameters. It uses static binding and can be checked at compile time.

Example: A Dog object and a Cat object both responding to the makeSound() method, but each producing a different sound.

Abstraction

Definition: Simplifying complex reality by focusing on essential characteristics and ignoring unnecessary details.

Purpose: Promotes code organization, modularity, and reusability.

Types: Abstract classes (cannot be instantiated directly) and interfaces (define a contract that concrete classes must implement).

Example: An Animal abstract class defining common methods like makeSound() and eat(), which concrete classes like Dog and Cat must implement.