java 接口与实现

public interface Computable {
   int MAX = 46;
   int f(int x);
}

public class China implements Computable {  //China类实现Computable接口
   int number;
   public int f(int x) { //不要忘记public关键字
      int sum=0;
      for(int i=1;i<=x;i++) {
         sum=sum+i;
      }
      return sum;
   }
}

public class Japan implements Computable { //Japan类实现Computable接口
   int number;
   public int f(int x) {
      return MAX+x; 
   }
}

public class Example6_1 {
   public static void main(String args[]) {
      China zhang; 
      Japan henlu;
      zhang=new China();   
      henlu=new Japan();  
      zhang.number=32+Computable.MAX; 
      henlu.number=14+Computable.MAX;
      System.out.println("zhang的学号"+zhang.number+",zhang求和结果"+zhang.f(100));
      System.out.println("henlu的学号"+henlu.number+",henlu求和结果"+henlu.f(100));
   }
}

abstract class MotorVehicles {
   abstract void brake();
}
interface MoneyFare {
   void  charge();
}
interface ControlTemperature {
   void controlAirTemperature();
}
class Bus extends MotorVehicles implements MoneyFare {
    void brake() {
        System.out.println("公共汽车使用毂式刹车技术");
    }
    public  void charge() {
        System.out.println("公共汽车:一元/张,不计算公里数");
    }
} 
class Taxi extends MotorVehicles implements MoneyFare,ControlTemperature {
    void brake() {
        System.out.println("出租车使用盘式刹车技术");
    }
    public  void charge() {
        System.out.println("出租车:2元/公里,起价3公里");
    }
    public void  controlAirTemperature() { 
        System.out.println("出租车安装了Hair空调");
    }

}
class Cinema implements MoneyFare,ControlTemperature {
    public  void charge() {
        System.out.println("电影院:门票,十元/张");
    }
    public void  controlAirTemperature() { 
       System.out.println("电影院安装了中央空调");
    }
}
public class Example6_2 {
   public static void main(String args[]) {
       Bus  bus101 = new Bus();
       Taxi buleTaxi = new Taxi();
       Cinema redStarCinema = new Cinema();
       bus101.brake(); 
       bus101.charge();
       buleTaxi.brake();
       buleTaxi.charge();
       buleTaxi.controlAirTemperature();
       redStarCinema.charge();
       redStarCinema.controlAirTemperature();
   }
}