# Class and Object

* **Definition of Class**

: Class is definition of object.

* **Usage of Class**

: Class is used for creating object.

| Class             | Object  |
| ----------------- | ------- |
| Product blueprint | Product |
| (Metaphor)붕어빵 기계  | 붕어빵     |

* **Components of Object : Properties and Function**

Object = Property(Variable) + Function(Method)

```java
class Tv {
    //Variable(=>Property)
    String color;
    boolean power;
    int channel;
    
    //Method(=>Function)
    void power() {power = !power;}
    void channelUp() {channel++;}
    void channelDown() {channel--;}
}
```

* **Object and Instance**

**Object** : Representative general terms of every Instance.

**Instance** : Created **Object** which is from specific Class.

Class ->(Instance화)->Instance(Object)

* Summary

1. Why need Class? To **create Object.**
2. Why need Object? To **use Object**.
3. What does using Object mean? **To use properties and function of Object**.