What are design patterns?
Answer: Christopher Alexander said: "Each pattern describes a problem that is recurring all around us, and the core of the solution to that problem. That way, you can use the solution again and again without having to do repetitive work."
Simply put, a design pattern is a summary of experience.
Classification of design patterns ( 23 types)?
Answer: Creation pattern ( 5 kinds) : singleton pattern, abstract factory pattern, factory method pattern, prototype pattern, builder pattern.
Structural mode ( 7 kinds) : proxy mode, adapter mode, decoration mode, bridge mode, combination mode, appearance mode, flyweight mode.
Behavior pattern ( 11 kinds) : Template method pattern, observer pattern, state pattern, responsibility chain pattern, command pattern, visitor pattern, strategy pattern, memorandum pattern, iterator pattern, interpreter pattern, mediator pattern.