Design Patterns

Design patterns are proven solutions to common problems in software development. They are not rigid rules, but guidelines.

Classification

1. Creational Patterns: Focus on how objects are created (e.g., Singleton, Factory).
2. Structural Patterns: How objects are organized and composed (e.g., Adapter, Composite).
3. Behavioral Patterns: How objects interact and communicate with each other.

State Pattern

Allows an object to change its behavior when its internal state changes. Ideal for avoiding many complex if/else statements.

Example: A music player with states Playing, Paused, Stopped.

Template Method Pattern

Defines the skeleton of an algorithm in a superclass, but lets subclasses override specific steps without changing the overall structure.

Example: A board game where all games have the steps start(), play() and end(), but each game implements them differently.