GoF Design Patterns in C# (Backend Focused)

This repository contains real-world backend-focused examples of the Gang of Four (GoF) design patterns using C#. The goal of this project is to learn and understand the design patterns and how these can be implemented. Each pattern includes a Bad version and a Refactored version, along with a runnable Program.cs for comparison.

✅ Implemented Design Patterns (Ordered by usefulness in backend)

1. Strategy (Behavioral) - Example
2. Observer (Behavioral) - Example
3. Factory Method (Creational) - Example
4. Decorator (Structural) - Example
5. Adapter (Structural) - Example
6. Command (Behavioral) - Example
7. Singleton (Creational) - Example
8. Builder (Creational) - Example
9. Proxy (Structural) - Example
10. Chain of Responsibility (Behavioral) - Example
11. Composite (Structural) - Example
12. Template Method (Behavioral) - Example
13. Facade (Structural) - Example
14. State (Behavioral) - Example
15. Abstract Factory (Creational) - Example
16. Mediator (Behavioral) - Example
17. Bridge (Structural) - Example
18. Flyweight (Structural) - Example
19. Prototype (Creational) - Example
20. Iterator (Behavioral) - Example
21. Memento (Behavioral) - Example
22. Interpreter (Behavioral) - Example
23. Visitor (Behavioral) - Example

Implemented Design Patterns Categorized into Behavioral, Structural and Creational

🎯 Behavioral Patterns

1. Strategy (Behavioral) - Example
2. Observer (Behavioral) - Example
3. Command (Behavioral) - Example
4. Chain of Responsibility (Behavioral) - Example
5. Template Method (Behavioral) - Example
6. State (Behavioral) - Example
7. Mediator (Behavioral) - Example
8. Iterator (Behavioral) - Example
9. Memento (Behavioral) - Example
10. Interpreter (Behavioral) - Example
11. Visitor (Behavioral) - Example

🏗️ Structural Patterns

12. Decorator (Structural) - Example
13. Adapter (Structural) - Example
14. Proxy (Structural) - Example
15. Composite (Structural) - Example
16. Facade (Structural) - Example
17. Bridge (Structural) - Example
18. Flyweight (Structural) - Example

🧱 Creational Patterns

19. Factory Method (Creational) - Example
20. Singleton (Creational) - Example
21. Builder (Creational) - Example
22. Abstract Factory (Creational) - Example
23. Prototype (Creational) - Example

🧠 About

• All examples are backend-centric
• Built using C# with runnable projects
• Clean separation of Bad vs Refactored
• Ideal for learning, interviews, and real-world projects

👋 Let’s Connect

• LinkedIn: sayyedulawwab
• Website: sayyedulawwab.com