Open Closed Principle

✅ OCP

• Open for extension: new code should be able to be extended
  • 확장에는 열려있고
• Closed for modification: old code must not be modified
  • 변경에는 닫혀있어야 한다

✅ How to implement OCP

• implement interface

• implement extends, abstract class

• even if a new car is added, open new class,
• driver class is not altered closed for modification

• distinguish code to be added and code not to be modified
• open : NewCar class 추가
• closed: Driver class, Car interface는 변하지 않음

✅ Strategy pattern

• have an interface
• and several classes that implement interface
• even if a new class is added, do not need to modify existing old classes
• easy to add a new class instance

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