类与对象&答答租车系统

(1) 定义一个车的父类;设置各种共有的属性（价格，序号,车名，容量）;

public class Car {

    protected int price;
    protected int id;        //序号 在租用界面给用户选择用;
    protected String name;   //车名
    protected int volume;    //货车载火量；
    protected int people;    //客车载人量；

    public Car() {
    }

    public Car(int id, String name, int volume, int price) {
        this.price = price;
        this.id = id;
        this.name = name;
        this.volume = volume;

}
}

(2) 定义两个接口,分别是载货、载人;提供给不同车类来实现它的功能;

public interface cargo {

     void transport();

}
///载人
public interface passenger {

    void carry();

}

（3）创建货车类,继承父类Car,实现接口Cargo;

public  class Track extends Car implements cargo {

    public Track(){

    }

    public Track(int id,String name,int volume,int price)
    {
        super(id,name,volume,price);
        System.out.println(id+","+"  "+name+" "+price+"元/天    载人"+volume+"人");
    }

    ///实现cargo接口的方法.
        public void transport() {

    }

}

（4）普通的客车

///普通的客车 继承父类Car,pessenger.接口.
    public  class Pessengers extends Car implements passenger {

        public Pessengers() {
            super();
        }

        public Pessengers(int id, String name, int volume, int price) {
            super(id, name, volume, price);
            System.out.println(id+","+"  "+name+" "+price+"元/天    载人"+volume+"人");

        }

///实现pessenger接口就要实现它所有的方法
        public void carry() {

        }

    }

（5）pickup类;

///集货车与客车功能于一身;要实现两个接口的方法;
public  class pickup extends Car implements cargo, passenger {

    public pickup() {
        super();
    }

    public pickup(int id, String name, int volume,int people, int price) {
        super(id, name, volume,price);
        this.people=people;
        System.out.println(id+","+"  "+name+" "+price+"元/天    载人:"+people+"人 载货："+volume+"吨");
    }

    public void carry() {

    }

    public void transport() {

    }

}

（6）主界面,租车系统类；

import java.util.Scanner;

public class rentsystem {
     Scanner sc=new Scanner(System.in);
    private Car[] car=new Car[]{
        new Pessengers(1,"奥迪A4",4,500),
        new Pessengers(2, "马自达",4,450),
        new pickup(3,"皮卡雪6",4,2,200),
        new Pessengers(4, "金龙",4,800),
        new Track(5,"松花江",4,400),
        new Track(6,"依维柯",20,1000)
    };

    public int sum=0;

    int choose(int num){

         int n = 0;
        for(int i=0;i<num;i++) //6
        {
            System.out.println("请输入第"+(i+1)+"辆车的序号 :");

            int x=sc.nextInt()-1;    
                                    ///根据输入的车型,返回相应的费用.
             switch(x)
             {
             case 0:
                 n=car[0].getPrice();
                 break;
             case 1:
                 n=car[1].getPrice();
                 break;
             case 2:
                 n=car[2].getPrice();
                 break;
             case 3:
                 n=car[3].getPrice();
                 break;
             case 4:
                n=car[4].getPrice();
                 break;
             case 5:
                 n=car[5].getPrice();
                 break;

             }
             sum+=n; 

        }
        return sum;

    }
}

（7）测试类

Public class test{
    public static void main(String[] args) {
        int total;
        int num;
        int sum;
        Scanner sc=new Scanner(System.in);

        System.out.println("欢迎使用DD租车系统");
        System.out.println("您是否要租车？1:是 0：否 ");
        int answer=sc.nextInt();
        if(answer==1)
        {

        System.out.println("您可租车的类型及其价目表");
        System.out.println("序号   汽车名称   租金       容量 ");
        rentsystem rt=new rentsystem();

         System.out.println("请输入您要租的汽车数量 ");    
         num=sc.nextInt();
         sum=rt.choose(num);

         System.out.println("请输入您要租的天数 ");  
         int day=sc.nextInt();
         total=day*sum;

         System.out.println("最后要租用的费用是： "+total);   

         answer++;
        }
        else
        {
             System.out.println("这家伙很懒啥也没看。 ");
        }
    }

}