Object-Oriented Programming

Object-oriented programming (OOP) is a programming paradigm centered around the concept of "objects". These objects are instances of classes, which serve as blueprints for creating individual objects. OOP is designed to improve the modularity and reusability of code by encapsulating data and operations within objects.

Key Concepts

Classes and Objects

A class is a blueprint for creating objects (a particular data structure), providing initial values for state (member variables or attributes), and implementations of behavior (member functions or methods). An object is an instance of a class, created using a constructor method, which initializes the object's properties.

Inheritance

In inheritance, a new class is created based on an existing class. The new class, referred to as a "subclass" or "derived class", inherits the attributes and methods of the "superclass" or "base class". This mechanism allows for code reusability and the creation of a hierarchy of classes that model the relationships between different entities.

Encapsulation

Encapsulation is a principle that restricts access to certain components of an object, providing a public interface while hiding its internal implementation details. This is achieved through access modifiers (such as private, protected, and public) which control the visibility of class members. Encapsulation helps in information hiding and reduces the impact of changes in the code.

Polymorphism

Polymorphism allows objects of different classes to be treated as objects of a common superclass. It enables a single function or method to work with different types of objects, enhancing flexibility and integration. Polymorphism is typically achieved in OOP through method overriding and overloading, allowing for dynamic method resolution at runtime.

Additional Concepts

Interfaces and Abstract Classes

An interface defines a contract for classes, specifying a set of methods that must be implemented. Abstract classes can provide a base implementation for some methods while leaving others to be implemented by subclasses. These constructs are used to achieve abstraction and decoupling in complex systems.

Object Composition

Object composition is a design principle that models a relationship where one object contains references to other objects. This principle is often preferred over inheritance as it often results in more flexible and modular design structures.

Factory Method Pattern

The factory method pattern is a creational design pattern that provides an interface for creating objects in a superclass but allows subclasses to alter the type of objects that will be created. It promotes loose coupling by delegating the task of instantiating objects to subclasses.