Object-Oriented Programming (OOP) Complete Guide
[日本語版](../../ja/02-programming/object-oriented-programming/SKILL.md)
SKILL.md
Full skill instructions
Object-Oriented Programming (OOP) Complete Guide
A comprehensive guide to understanding and effectively applying object-oriented programming. Covers the four pillars, SOLID principles, design patterns, and anti-patterns with MIT-level quality.
Target Audience
- Engineers who want to systematically learn OOP from fundamentals to advanced topics
- Developers seeking practical understanding of SOLID principles and design patterns
- Anyone looking to sharpen their judgment on "inheritance vs composition" and "when to use OOP"
Prerequisites
- Programming basics (variables, functions, control flow)
- Experience with at least one programming language
Guide Index
00-introduction (Introduction)
| File | Topic | Summary |
|---|---|---|
| 00-what-is-oop.md | What is OOP | The essence of object-oriented thinking, mental models, and how it fits among other paradigms |
| 01-history-and-evolution.md | History and Evolution of OOP | Evolution from Simula to Smalltalk to C++ to Java to modern languages |
| 02-oop-vs-other-paradigms.md | OOP vs Other Paradigms | Comparison with procedural, functional, and reactive paradigms; when to use each |
| 03-class-and-object.md | Classes and Objects | Internal structure of classes, memory layout, constructors, static members |
01-four-pillars (The Four Pillars)
| File | Topic | Summary |
|---|---|---|
| 00-encapsulation.md | Encapsulation | Information hiding, access modifiers, immutable objects, the getter/setter debate |
| 01-inheritance.md | Inheritance | Single/multiple inheritance, the diamond problem, abstract classes, pitfalls of inheritance |
| 02-polymorphism.md | Polymorphism | Subtype, parametric, and ad-hoc polymorphism; dynamic dispatch; virtual function tables |
| 03-abstraction.md | Abstraction | Interface design, abstract classes vs interfaces, leaky abstractions |
02-design-principles (Design Principles)
| File | Topic | Summary |
|---|---|---|
| 00-solid-overview.md | SOLID Principles Overview | The big picture of all five principles, why SOLID matters, criteria for applying them |
| 01-srp-and-ocp.md | SRP + OCP | Single Responsibility Principle, Open/Closed Principle, practical examples |
| 02-lsp-and-isp.md | LSP + ISP | Liskov Substitution Principle, Interface Segregation Principle |
| 03-dip.md | DIP | Dependency Inversion Principle, Dependency Injection (DI), IoC Containers |
03-advanced-concepts (Advanced Concepts)
| File | Topic | Summary |
|---|---|---|
| 00-composition-vs-inheritance.md | Composition vs Inheritance | Why "favor composition over inheritance," practical decision criteria |
| 01-interfaces-and-traits.md | Interfaces and Traits | Implementations in Java/TypeScript/Rust/Go, duck typing |
| 02-mixins-and-multiple-inheritance.md | Mixins and Multiple Inheritance | Python MRO, Ruby modules, TypeScript Mixins |
| 03-generics-in-oop.md | Generics in OOP | Type parameters, covariance/contravariance, type erasure vs monomorphization |
04-practical-patterns (Practical Patterns)
| File | Topic | Summary |
|---|---|---|
| 00-creational-patterns.md | Creational Patterns | Factory, Builder, Singleton, Prototype |
| 01-structural-patterns.md | Structural Patterns | Adapter, Decorator, Facade, Proxy, Composite |
| 02-behavioral-patterns.md | Behavioral Patterns | Strategy, Observer, Command, State, Iterator |
| 03-anti-patterns.md | Anti-Patterns | God Object, deep inheritance hierarchies, Anemic Domain Model |
Learning Path
Fundamentals: 00-introduction -> 01-four-pillars
Principles: 02-design-principles (SOLID)
Applied: 03-advanced-concepts -> 04-practical-patterns