父类

package com.dadarentcar;

public abstract class Vehicle {
    protected String name;
    protected double price;
    protected int mannedNumber;
    protected int carryFreightNumber;

    public abstract boolean manned();
    public abstract boolean carry();

}

子类

package com.dadarentcar;
/*
 * 汽车可以载人，但是不能载物；
 */

public class Car extends Vehicle {
    public Car(String name,double price,int mannedNumber){
        this.name = name;
        this.price = price;
        this.mannedNumber = mannedNumber;
    }

    @Override
    public boolean manned() {
        // TODO Auto-generated method stub
        System.out.println("可以载人数为：" + mannedNumber);
        return true;
    }

    @Override
    public boolean carry() {
        // TODO Auto-generated method stub
        System.out.println("错误，不可以载物");
        return false;
    }

}

package com.dadarentcar;
/*
 * 可以载物，但是不可以载人
 */

public class Van extends Vehicle {
    public Van(String name,double price,int carryFreightNumber){
            this.name = name;
            this.price = price;
            this.carryFreightNumber = carryFreightNumber;
        }

    @Override
    public boolean manned() {
        // TODO Auto-generated method stub
        System.out.println("错误，不可以载人");
        return false;
    }

    @Override
    public boolean carry() {
        // TODO Auto-generated method stub
        System.out.println("可以载物的重量为："+carryFreightNumber);
        return true;
    }

}

package com.dadarentcar;
/*
 * 皮卡可以载物也可以载人
 */

public class PickUpTruck extends Vehicle {
    public PickUpTruck(String name,double price,int mannedNumber,int carryFreightNumber) {
        this.name = name;
        this.price = price;
        this.carryFreightNumber = carryFreightNumber;
        this.mannedNumber = mannedNumber;
    }
    @Override
    public boolean manned() {
        // TODO Auto-generated method stub
        System.out.println("可以载人数为：" + mannedNumber);
        return true;

    }

    @Override
    public boolean carry() {
        // TODO Auto-generated method stub
        System.out.println("可以载物的重量为："+carryFreightNumber);
        return true;
    }

}

main方法

package com.dadarentcar;

import java.util.Scanner;

public class Initial {

    public static void main(String[] args) {
        int number = 0;//租车的数量
        int days = 0;//租车的时间
        double totalPrice = 0;//租车的总价格
        Vehicle[] choose = { new Car("奥迪A4", 500, 4), new Car("马自达6", 400, 4), new PickUpTruck("皮卡雪6", 450, 4, 2),
                new Car("金龙", 800, 20), new Van("松花江", 400, 4), new Van("依维柯", 1000, 20) };
        int i = choose.length;

        System.out.println("欢迎使用达达租车系统:");
        while(true) {// 菜单，可以用方法写，这里直接写在main里
            System.out.println("您是否需要租车：1是 0否");

            Scanner input = new Scanner(System.in);
            int comfirm = input.nextInt();
            if (comfirm == 0) {
                break;// 跳出租车系统
            }else if(comfirm != 1){
                System.out.println("请输入正确的数字");
                continue;
            }

            System.out.println("您可租车的类型及价目表如下：");
            System.out.println("序号\t汽车名称\t租金\t容量");
            for (int l = 0; l < i; l++) {
                System.out.println(l+1 + ".\t" + inf(choose[l]));
            }

            System.out.println("请输入租车的数量：");
            number = input.nextInt();
            int[] vehicleNumber = new int[number];
            Vehicle[] vehicleChoose = new Vehicle[number];

            for(int l = 0; l < number; l++){
                int h = l+1;
                System.out.println("请输入第" + h + "辆车的序号");
                int m  = input.nextInt();
                if(m>=1&&m<=i){
                    vehicleChoose[l] = choose[m-1];
                }else{
                    System.out.println("输入错误，请重新输入....");
                    l--;
                }
            }

            System.out.println("请输入租车的天数：");
            days = input.nextInt();

            for(int l = 0; l < number; l++){
                totalPrice += vehicleChoose[l].price ;
            }
            totalPrice *= days;
            bill(vehicleChoose);
            System.out.println("***租车的总价格：" + totalPrice + "元");

            break;
        }
        System.out.println("按任意键退出。。。。");

    }

    public static String inf(Vehicle veh) {// 显示交通工具信息
        String a = "";
        if (veh instanceof Car) {
            a = veh.name + "\t" + veh.price + "元/天\t载人：" + veh.mannedNumber + "人";
        }
        if (veh instanceof Van) {
            a = veh.name + "\t" + veh.price + "元/天\t载货：" + veh.carryFreightNumber + "吨";
        }
        if (veh instanceof PickUpTruck) {
            a = veh.name + "\t" + veh.price + "元/天\t载人：" + veh.mannedNumber + "人 载货:" + veh.carryFreightNumber + "吨";
        }

        return a;
    }

    public static void bill(Vehicle[] veh){
        int l = veh.length;
        String a1 = "";
        String a2 = "";
        int man = 0;
        int goods = 0;
        System.out.println("您的账单：");
        for(int i = 0; i < l; i++){
            if(veh[i] instanceof Carveh[i] instanceof PickUpTruck){
                a1 = a1 + veh[i].name + "\t";
                man += veh[i].mannedNumber;
            }
            if(veh[i] instanceof Vanveh[i] instanceof PickUpTruck){
                a2 = a2 + veh[i].name + "\t";
                goods += veh[i].carryFreightNumber;
            }
        }
        System.out.println("***可载人的车有：");
        System.out.println(a1 + "共载人："+ man + "人");
        System.out.println("***载货的车有：");
        System.out.println(a2 + "共载货："+ goods + "吨");
    }
}