JAva oop 21単一継承

  public class Oop21_singleInheritance {

    public static void main(String[] args) {
        TvDVD tt = new TvDVD();

        tt.notice("전원이 켜졌습니다.");
        tt.whatsmodel();
        tt.channelUp();
        System.out.println(tt.channel);

    }
}
class Tv2{
    boolean power;
    int channel;

    void power() {
        power = !power;
    }
    void channelUp() {
        ++channel;
    }
    void channelDown() {
        --channel;
    }
}
class DVD{
    boolean power;
    String modelname = "삼성01NB";

    void power(){ power = !power;}
    void notice(String txt) { System.out.println(txt); }
    void play(){    }
}
class TvDVD extends Tv2{
    DVD dd = new DVD();
    //객체생성해서 객체로 메서드나 변수 사용하기

    void notice(String text){
        dd.notice(text);
    }
    void whatsmodel() {
        System.out.println(dd.modelname);
    }
}