Object Oriented Programming

☑️ Sequential Programming

• program runs by order
• unstructued programming
• 👎🏻 if need code from before, use goto
• need to pay attention to flow(in what order will this code be run), instead of code developemnt

☑️ Procedural Programming

• structured programming
• repreated codes are made into method(procedure)
• procedure: method that does not return
• 👎🏻 too abstract

✅ Obejct Oriented Programming

• 현실 세계를 프로그래밍 세계로 옮겨와 현실 세계의 사물들을 객체로 생각
• 객체의 특징, 기능을 뽑아 프로그래밍
• class has field, getter, setter
• to manage an object’s field and method toegether

What are the benefits of OOP?

👍🏻 code reuseablility
👍🏻 can adapt code for several purposes

👍🏻 Abstraction

- fish, cat, dog all fit in animal
- animal is abstraction
- get all common characteristics, into one object

why use abstraction?

if tiger is added, need to develop just the new part for animal istead of developing all over again .

👍🏻 Encapsulation

if alternation happens, minimize impact on other codes
minimize coupling
minimize dependencies of independent objects

• use private field

👍🏻 Inheritence

another type of encapulsation capsulize child class from public

👍🏻 Polymorphism

child class can override parent class method, and use it as it wants

✅ SOLID

OOP 설계 원칙
how to program object oriented

1. SRP

Single Responsibility
class should have one responsibility

• not to affect other codes

2. OCP

Open Closed Policy

• open for expansion, closed for update
• can update or change function, however do not change the code.

3. LSP

Liskov Substitution Principle

• object of a superclass should be replaceable with an object of a subclass without affecting the correctness or consistency of the program’s behavior

4. ISP

Interface Segregation Principle

• interface should be seperate

5. DIP

Dependency Inversion Principle

• should depend on abstraction
• 추상화(인터페이스)에 의존해야 하며, 구체화(구현된 클래스)에 의존해서는 안된다.