父类：Car.java

package www.dadacar;

public class Car {
    protected String carName;
    protected double carRent;
    //有参构造方法，赋值车名称和租金
    public Car(String carname,double carrent){
        this.carName = carname;
        this.carRent = carrent;
    }
    //利用右击-Generate，自动生成getter和setter函数
    public String getCarName() {
        return carName;
    }

    public void setCarName(String carName) {
        this.carName = carName;
    }

    public double getCarRent() {
        return carRent;
    }

    public void setCarRent(double carRent) {
        this.carRent = carRent;
    }
}

子类：Passenger.java

package www.dadacar;

class PassengerCar extends Car {
    private int peopleCapacity;
    //构造方法，赋值载客量
    public PassengerCar(String carname,double carrent,int peoplecapacity){
        super(carname,carrent);       //因为父类是有参构造方法，要用super调用
      this.peopleCapacity=peoplecapacity;
    }
    public int getPeopleCapacity() {
        return peopleCapacity;
    }
    public void setPeopleCapacity(int peopleCapacity) {
        this.peopleCapacity = peopleCapacity;
    }
}

子类：Truck.java

package www.dadacar;

public class Truck extends Car {
    private double cargoCapacity;
    //构造方法，赋值载货量
    public Truck(String carname,double carrent,double cargocapacity){
        super(carname,carrent);
        this.cargoCapacity = cargocapacity;
    }

    public double getCargoCapacity() {
        return cargoCapacity;
    }

    public void setCargoCapacity(double cargoCapacity) {
        this.cargoCapacity = cargoCapacity;
    }
}

子类：PickUp.java

package www.dadacar;

public class PickUp extends Car {
    private int peopleCapacity;
    private double cargoCapacity;
    //构造方法，赋值载客量和载货量
    public PickUp(String carname,double carrent,int peoplecapacity,double cargocapacity){
        super(carname,carrent);
        this.cargoCapacity=cargocapacity;
        this.peopleCapacity=peoplecapacity;
    }

    public int getPeopleCapacity() {
        return peopleCapacity;
    }

    public void setPeopleCapacity(int peopleCapacity) {
        this.peopleCapacity = peopleCapacity;
    }

    public double getCargoCapacity() {
        return cargoCapacity;
    }

    public void setCargoCapacity(double cargoCapacity) {
        this.cargoCapacity = cargoCapacity;
    }
}

主方法：TestSoftware.java

package www.dadacar;
import java.util.Scanner;
import java.util.Arrays;

public class TestSoftware {
    public static void main(String[] args) {
        System.out.println("欢迎使用答答租车系统");
        System.out.println("您是否要租车：1是，0否");
        //利用Scanner获取输入信息
        Scanner input = new Scanner(System.in); //定义一次即可，后面均可引用input
        int isOrno = input.nextInt();
        if(isOrno == 1){
            //创建一个包含六个车对象的数组
            Car[] cars = {new PassengerCar("奥迪A4",500,4),
                    new PassengerCar("马自达6",400,4),
                    new PickUp("皮卡雪6",450,4,2),
                    new PassengerCar("金龙",800,20),
                    new Truck("松花江",400,4),
                    new Truck("依维柯",1000,20)
            };
            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"+"\t"+"\t"+"容量");
            int i = 1;
            //利用foreach遍历数组cars，依次进行显示
            for(Car carCurrent:cars){
                //判断当前数组对象是否为载人汽车
                if(carCurrent instanceof PassengerCar){
                    System.out.println(""+i +".\t"+
                            carCurrent.carName+"\t"+
                            carCurrent.carRent+"元/天"+"\t"+
                            "载人："+((PassengerCar) carCurrent).getPeopleCapacity()+"人");
                }
                //判断当前数组对象是否为货车
                if(carCurrent instanceof Truck){
                    System.out.println(i + ".\t"+
                            carCurrent.carName+"\t"+
                            carCurrent.carRent+"元/天"+"\t"+
                            "载货："+((Truck) carCurrent).getCargoCapacity()+"吨");
                }
                //判断当前数组对象是否为皮卡车
                if(carCurrent instanceof PickUp){
                    System.out.println(i + ".\t"+
                            carCurrent.carName+"\t"+
                            carCurrent.carRent+"元/天"+"\t"+
                            "载人："+((PickUp) carCurrent).getPeopleCapacity()+"人 "+
                            "载货："+((PickUp) carCurrent).getCargoCapacity()+"吨");
                }
                i ++;
            }
            System.out.println("请输入您要租汽车的数量：");
            //获取租车数量
            int carNums = input.nextInt();
            //创建一个数组，长度为租车数量，用于放置租车序号
            int[] carNum = new int[carNums];
            //遍历租车数组，并存储汽车序号
            for(int j = 1;j <= carNums; j ++ ){
                System.out.println("请输入第"+j+"辆车的序号：");
                carNum[j-1]= input.nextInt();
            }
            //System.out.println(Arrays.toString(carNum)); //输出租车序号数组，检验代码是否正确
            System.out.println("请输入租车天数：");
            //获取租车天数
            int carDays = input.nextInt();
            System.out.println("您的账单为：");
            System.out.println("***可载人的车有：");
            //定义一个变量存储总租金，注意变量的类型
            double sumRent = 0;
            //定义一个变量存储总载人数
            int numPeople = 0;
            //定义一个变量存储总载货量
            double numCargo = 0;
            //遍历所有选择的租车序号数组，输出租车汽车名称，计算总载人数、总租金和总载货量
            for(i = 0; i<=carNums-1; i++) {
                //判断当前车是否为载人汽车
                if(cars[carNum[i]-1] instanceof PassengerCar){
                    //将当前cars对象的类向下转型，便于获取子类中定义的函数getPeopleCapacity()
                    PassengerCar carCurrent = (PassengerCar) cars[carNum[i]-1];
                    System.out.print(carCurrent.carName + "\t");
                    numPeople = numPeople + carCurrent.getPeopleCapacity();
                    sumRent += carCurrent.carRent;
                }
                //判断当前车是否为皮卡车
                if(cars[carNum[i]-1] instanceof PickUp){
                    //将当前cars对象的类向下转型，便于获取子类中定义的函数getPeopleCapacity()
                    PickUp carCurrent = (PickUp) cars[carNum[i]-1];
                    System.out.print(carCurrent.carName + "\t");
                    numPeople = numPeople + carCurrent.getPeopleCapacity();
                    sumRent += carCurrent.carRent;
                }
            }
            System.out.println("共载人:"+numPeople+"人");
            System.out.println("***可载货的车有：");

            for(i = 0; i<=carNums-1; i++) {
                if(cars[carNum[i]-1] instanceof Truck){
                    Truck carCurrent = (Truck) cars[carNum[i]-1];
                    System.out.print(carCurrent.carName + "\t");
                    numCargo = numCargo + carCurrent.getCargoCapacity();
                    sumRent += carCurrent.carRent;
                }
                if(cars[carNum[i]-1] instanceof PickUp){
                    PickUp carCurrent = (PickUp) cars[carNum[i]-1];
                    System.out.print(carCurrent.carName + "\t");
                    numCargo = numCargo + carCurrent.getCargoCapacity();
                    sumRent += carCurrent.carRent;
                }
            }
            System.out.println("共载货:"+numCargo+"吨");
            System.out.println("***租车总价格为"+(sumRent*carDays));

        }else{
            System.out.println("期待您选择答答租车系统");
        }
    }
}