代码初步写成这样，希望能够得到改进意见，谢谢

package com.demo;

import java.util.ArrayList;

import java.util.List;

import java.util.Scanner;

public class Rental {

/**

* @param args

*/

public static void main(String[] args) {

System.out.println("欢迎使用答答租车系统！");

System.out.println("是否进入租车界面：");

System.out.println("1:进入   0:退出");

Scanner putInScanner = new Scanner(System.in);

int putIn = putInScanner.nextInt();

if (putIn==1) {

System.out.println("可选择车的类型及其价目：");

System.out.println("序号"+"\t"+"汽车名称"+"\t\t"+"租金(元/天)"+"\t"+"载人量（人）"+"\t"+"载货量（吨）");

Car[] cars = {new Coach(1, "奥迪A4", 500, 4,0),new Coach(2, "马自达6", 400, 4,0)

,new PickUP(3, "皮卡雪6", 450, 4,2),new Coach(4, "金龙", 800, 20,0)

,new Truck(5,"松花江",400,0,4),new Truck(6,"依维柯",1000,0,20)};

//显示价目表

for (Car car : cars) {

System.out.println(car.getId()+"\t"+car.getCarName()+"\t\t"+car.getCarRent()+"\t\t"+

car.getNumber()+"\t\t"+car.getCargoes());

}

System.out.println("请输入租车的数目：");

List<Car> carList = new ArrayList<Car>();

for (int i = 0; i < cars.length; i++) {

carList.add(cars[i]);

}

int money = 0;//总钱数

int amount = putInScanner.nextInt();

for (int i = 0; i < amount; i++) {

int oneMoney = 0;//单个的钱数

System.out.println("请输入第"+(i+1)+"辆车的序号");

int num = putInScanner.nextInt();

System.out.println("该车使用几天：");

int day = putInScanner.nextInt();

System.out.println("已成功添加："+carList.get(num-1).getCarName());

oneMoney = carList.get(num-1).getCarRent()*day + oneMoney;

System.out.println("该车花费"+oneMoney+"元");

money = money + oneMoney;

}

System.out.println("总计金额："+money+"元");

System.out.println("感谢您的使用，再见！");

} else {

System.out.println("已退出租车系统！");

}

}

}

package com.demo;

/**

 * 抽象类：车

 * @author Administrator

 *

 */

public class Car {

private int id;//序号

private int number;//载人量

private int cargoes;//载货量

private String carName;//车名

private int carRent;//租金

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public int getNumber() {

return number;

}

public void setNumber(int number) {

this.number = number;

}

public int getCargoes() {

return cargoes;

}

public void setCargoes(int cargoes) {

this.cargoes = cargoes;

}

public String getCarName() {

return carName;

}

public void setCarName(String carName) {

this.carName = carName;

}

public int getCarRent() {

return carRent;

}

public void setCarRent(int carRent) {

this.carRent = carRent;

}

//id：序号；carName：汽车名称；rent：租金；number：载人量；cargoes：载货量

public Car(int id,String carName,int rent,int number,int cargoes){

this.setId(id);

this.setCarName(carName);

this.setCarRent(rent);

this.setCargoes(cargoes);

this.setNumber(number);

}

}

package com.demo;

/**

 * 货车

 * @author Administrator

 *

 */

public class Truck extends Car{

public Truck(int id, String carName, int rent, int number, int cargoes) {

super(id, carName, rent, number, cargoes);

this.setId(id);

this.setCarName(carName);

this.setCarRent(rent);

this.setCargoes(cargoes);

this.setNumber(number);

}

}

package com.demo;

/**

 * 客车

 * @author Administrator

 *

 */

public class Coach extends Car {

public Coach(int id, String carName, int rent, int number, int cargoes) {

super(id, carName, rent, number, cargoes);

this.setId(id);

this.setCarName(carName);

this.setCarRent(rent);

this.setCargoes(cargoes);

this.setNumber(number);

}

}

package com.demo;

/**

 * 皮卡

 * @author Administrator

 *

 */

public class PickUP extends Car {

public PickUP(int id, String carName, int rent, int number, int cargoes) {

super(id, carName, rent, number, cargoes);

this.setId(id);

this.setCarName(carName);

this.setCarRent(rent);

this.setCargoes(cargoes);

this.setNumber(number);

}

}