OOP Concepts

concept Object-Oriented Programming (OOP) is a programming paradigm based on the concept of “objects,” which can contain data (fields) and code (methods). It dominates enterprise software and GUI development.

The Core Philosophy

Unlike Procedural Programming (C), which separates Data and Logic, OOP bundles them together.

• Procedural: process_data(data)
• OOP: data.process()

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The Four Pillars of OOP

1. Encapsulation: Hiding the internal state and requiring all interaction to occur through an object’s methods. (Private vs Public).
2. Inheritance: Creating new classes based on existing ones to reuse code. (Dog is-a Animal).
3. Polymorphism: The ability of different classes to respond to the same message/function call in different ways. (The “Shape” class has a draw() method, but Circle and Square implement it differently).
4. Abstraction: Hiding complex implementation details and showing only the necessary features of an object.

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OOP in Systems Programming

• C++: The classic Systems OOP language. Adds Classes to C.
• C: Simulates OOP using structs and function pointers (e.g., the Linux Kernel file_operations struct).
• Rust: Not strictly OOP, but uses structs and impl blocks to achieve Encapsulation, and Traits to achieve Polymorphism.

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