Class Variable and Instance Variable

When make "Card" class, the width and height is same and common. The pattern and number are different.

class Card {
    String pattern;
    int number;
    
    static int width = 100;
    static int height = 250;
}

• Class Variable(static variable, sharing variable)

Common properties all Instances have. ex) width, height

Card.width = 200;
Card.height = 300;

Card c = new Card();
//가능은 하지만 권장하지 않는다
//c.width = 200;
//c.height = 300;

• Instance Variable

Individual properties. ex) pattern, number

Card c = new Card();

c.pattern = "HEART";
c.number = 5;