Java-13，static关键字

public class Cat {
    private static int sid = 0;
    private String name;
    private int id;
    
    Cat(String name){
        this.name = name;
        id = sid++;
    }
    
    public void info(){
        System.out.println("My name is "+name+" No."+id);
    }
    
    public static void main(String[] args) {
        Cat.sid = 100;
        Cat mimi = new Cat("mimi");
        Cat pipi = new Cat("pipi");
        mimi.info();
        pipi.info();
    }
}