Kotlin classes can organize code into reusable blocks of logic and data. A class defines properties and functions to model real-world concepts or business logic. To instantiate a class, its primary constructor is called to create an object instance. Class properties can be mutable or read-only, and computed properties derive values from other properties. Functions defined inside classes are called methods. Initialization code runs before property setters via an init block.

1. Kotlin
Defining classes
Julian/小朱 : 以下內容不保證正確性(?

2. Overview
- Class
- How to instantiate a class by calling constructor
- Class Functions
- Visibility and Encapsulation
- Class Properties
- Property visibility
- Computed properties
- Val vs var: read-only vs writable
- Race Conditions

3. Class是什麼?
可以吃嗎?

4. What is Class
Class , Object real world:
business logic / model
Code

5. How does class organize code

6. How to instantiate class
Call constructor to create instance:

7. Class definition

8. https://kotlinlang.org/docs/reference/coding-conventions.html

9. inheritance
behaviour
and data
visibility

10. Classes in Kotlin

11. Access Modifier
Source: Kotlin in Action

12. Visibility Modifier
- Top-level declaration
- class member
Source: Kotlin in Action

13. Top-level
visibility

14. Class
member
visibility

15. Data and behaviour
in class body
● Class property
- Property with implicit getter and setter
- Backing field
- Backing property
● Class function

16. Custom getter and setter(Backing field)

17. var and val: writable vs read-only
val: getter(read-only)
var: getter and setter(writable)

18. Computed property

19. Function vs
Method
OOP: method is a function in class
-> Kotlin: class function

20. Object vs
Object vs
Object
OOP instance of a class
java/c# base class
Kotlin keyword: like static in java/c#

21. Init for primary constructor
Source: Kotlin in action
Source: 本書 https://stackoverflow.com/questions/5535683
7/what-is-the-difference-between-init-block-a
nd-constructor-in-kotln
Source:
https://kotlinlang.org/docs/reference
/classes.html

22. Why init
we don’t need init (validated by setter)
we need init
Something we can’t do in setter, getter
and primary constructor

23. Call primary constructor
Call secondary constructor