习题（转载，）

 public class fulei {
     public fulei()
     {
         System.out.println("欢迎使用海尔");
     }
     public String Pinpai;
     public String Xinghao;
     public fulei(String pinpai, String xinghao)
     {
         this.Pinpai = pinpai;
         this.Xinghao = xinghao;
         System.out.println(Pinpai+"饮水机\n"+"型号为"+Xinghao);
     }
     int t = 0;
     public void reshui(int 时间)
     {
         t = 时间;
         if(t > 15&&t<20)
         {
              System.out.println("保温");
         }
         else
         {
             System.out.println("加热");
         }
     }
     public void xiaodu(int 时间1)
     {
         t = 时间1;
         if(t >= 20)
         {
             System.out.println("消毒");
         }
     }
 }

public class zilei1 extends fulei
{
    public zilei1 (String Pinpai, String Xinghao)
    {
        super (Pinpai, Xinghao);
    }
    public zilei1()
    {
        String Pinpai = "美的";
        String Xinghao = "HB350";
        System.out.println("我是"+Pinpai+Xinghao);
    }
    int t;
    public void xiaodu(int t)
    {
        if(t > 65)
        {
            System.out.println("正在消毒");
        }
    }
}

 
     public static void main(String[] args) {
         // TODO Auto-generated method stub
         fulei ysj1 = new fulei();
         fulei ysj = new fulei("Haier", "GB125");
             ysj.reshui(6);
             ysj.xiaodu(70);
             ysj.reshui(16);
             
         zilei1 ysj2 = new zilei1();
             ysj2.xiaodu(70);
             
         //向上转型调用方法    
             fulei ysj3 = new zilei1();
             ysj3.xiaodu(80);
     }
 
 }