Design patterns are general, reusable solutions to common software design problems. They are not specific to any programming language, but rather provide a common language to communicate between developers. There are 23 design patterns that are commonly used in software development today, divided into three main categories: Creational, Structural, and Behavioral.
Creational patterns are used to create objects. They help to create objects without exposing the logic behind their creation. Examples include Abstract Factory, Builder, Factory Method, Object Pool, Prototype, and Singleton.
Structural patterns are used to design the structure of objects. They help to build different objects and provide a way to compose them together. Examples include Adapter, Bridge, Composite, Decorator, Facade, Flyweight, and Proxy.
Behavioral patterns are used to design the behavior of objects. They help to define the communication between objects and the way they interact with each other. Examples include Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, and Visitor.
Design patterns provide a common language for developers to communicate and understand the design decisions of a software system. The 23 design patterns provide a wide range of solutions to common software design problems. Each pattern has its own advantages and disadvantages, so it is important to choose the right pattern for the right situation. With the right design pattern, you can create robust, maintainable, and extensible software designs.