今天用JAVA编写了一个租车系统，过程中主要遇到的两个问题：

1、输出数组信息问题：

在得到cars[]数组后，要生成租车信息表，目前有两种思路：一是用循环输出；二是用Arrays.toString()输出数组信息。

用toString()方法输出数组输出……@……形式的哈希码地址，这里需要对toString()方法进行重写，在数组涉及到的类中进行重写。

不过用第二种方法输出的其实还是一个数组，形式如图所示。那么问题来了——还有没有更好的输出方法呢？

2、父类方法不能访问子类成员变量：

本来在父类Car中写好的getPersonCapacity()和getGoodCapacity()方法似乎不能访问子类中的personCapacity和goodCapacity 这两个成员变量，导致调用参数时始终为0；所以在各子类方法中又独立加上了前面两个方法，问题得以解决。

运行效果图：

代码如下：

package rentCarSys;
/*
 * 总共有三种车型：载人Auto，载货Van，载人载货Pickup
 * Car 为这三种车型的父类
 * 有4种属性：
 * 编号 = number
 * 品牌 = brand
 * 租金/天 = fee
 * 载人容量 = personCapacity
 * 载货容量 = goodCapacity
 */
public class Car {
	int number;
	String brand;
	double fee;
	int personCapacity;
	double goodCapacity;
	
	public  Car(int number, String brand, double fee){   //构造方法
		this.number = number;
		this.brand = brand;
		this.fee = fee;
	}
	
	public int getNumber(){
		return number;
	}
	
	public String getBrand(){
		return brand;
	}
	
	public double getFee(){
		return fee;
	}
	
	public int getPersonCapacity(){
		return personCapacity;
	}
	
	public double getGoodCapacity(){
		return goodCapacity;
	}
	
}

package rentCarSys;
/*
 * Auto为载人汽车，除了Car中的属性之外还有载人容量 personCapacity
 */
public class Auto extends Car{
	
	private int personCapacity;

	public Auto(int number, String brand, double fee, int personCapacity) {
		
		super(number, brand, fee);
		this.personCapacity = personCapacity;
	}
	
	public int getPersonCapacity() {
		return personCapacity;
	}
	
	@Override
	public String toString() {
		return number + "t" + brand + "t" + fee + "元/天t" + personCapacity + "人n";
	}
	
}

package rentCarSys;
/*
 * Van为载货汽车，除了Car中的属性之外还有载货容量 goodCapacity
 */
public class Van extends Car{
	
	private double goodCapacity;
	
	public Van(int number, String brand, double fee, double goodCapacity) {
		
		super(number, brand, fee);
		this.goodCapacity = goodCapacity;
		
	}
	
	public double getGoodCapacity(){
		return goodCapacity;
	}
	
	public String toString() {
		return number +  "t" + brand + "t" + fee + "元/天t" + goodCapacity + "吨" + "n";
	}
	
}

package rentCarSys;
/*
 * Pickup为载人载货汽车，除了Car中的属性之外还有载人容量 personCapacity,载货容量goodCapacity
 */
public class Pickup extends Car{

	private int personCapacity;
	private double goodCapacity;
	
	public Pickup(int number, String brand, double fee, int personCapacity, double goodCapacity) {
		
		super(number, brand, fee);
		this.personCapacity = personCapacity;
		this.goodCapacity = goodCapacity;
		
	}
	
	public int getPersonCapacity() {
		return personCapacity;
	}
	
	public double getGoodCapacity(){
		return goodCapacity;
	}
	
	@Override
	public String toString() {
		return number +  "t" + brand + "t" + fee + "元/天t" +
	personCapacity + "人t" + goodCapacity + "吨n";
	}
}

package rentCarSys;

import java.util.Arrays;
import java.util.Scanner;

public class Login {

	public static void main(String[] args){
		
		Scanner input = new Scanner(System.in);
		Car[] cars = new Car[6];
		
		System.out.print("欢迎使用答答租车系统：");
		System.out.print("您是否要租车？1、是  2、否（请输入1或2）");
		int input1 = input.nextInt();
		if (input1 == 1){
			System.out.println("下面是所有车的信息：");
			
			cars[0] = new Auto(1, "奥迪A4", 500.0, 4);
			cars[1] = new Auto(2, "马自达6", 400.0, 4);
			cars[2] = new Pickup(3, "皮卡雪6", 450.0, 4, 2);
			cars[3] = new Auto(4, "金龙", 800.0,  20);
			cars[4] = new Van(5, "松花江", 400.0, 4);
			cars[5] = new Van(6, "依维柯", 1000.0, 20);
			
			System.out.println("序号t" + "汽车名称t" + "租金tt" + "容量(载人/载货)");
			System.out.println(Arrays.toString(cars));
//			for(int i = 0; i < cars.length; i++){
//				System.out.println("编号:"+ (i+1) +"   品牌:"+ cars[i].getBrand() 
//							+"   租金:"+ cars[i].getFee() +"/天       载客量:"+ cars[i].getPersonCapacity()+"人"
//							+"   载货量:"+ cars[i].getGoodCapacity()+"吨" );
//			}
		}else{
			System.out.println("谢谢使用，再见！");
		}
	
		System.out.print("请输入你要租几种车：");
		int rentNum = input.nextInt();
		
		//selected用来保存客户选中了什么车型，以及每种车型的辆数，与car数组是对应关系
		int[] selected = new int[6];
		
		for (int i = 1; i <= rentNum; i++){
			System.out.println("请输入第" + i + "种车型的序号：" );
			int nums = input.nextInt() - 1;
			System.out.println(cars[nums].getBrand() +"总共需要多少辆：");
			int num = input.nextInt();
			selected[nums] = num;
		}
		
		System.out.println("请输入租车天数：");
		int daysNum = input.nextInt();

		System.out.println("您的账单：--------------------------");
		double total = 0;
		for (int i = 0; i < cars.length; i++){
			if (selected[i] !=0 ){
				System.out.println(selected[i] + "辆" + cars[i].getBrand() +
						"   总共载客量:"+selected[i]*cars[i].getPersonCapacity()+"人"+
						"   总共载货量:"+selected[i]*cars[i].getGoodCapacity()+"吨"+
						"   "+daysNum+"天单项费用:"+selected[i]*cars[i].getFee()*daysNum+"元");
				total += selected[i]*cars[i].getFee()*daysNum;
			}
		}
		System.out.println("租车总费用：" + total + "元" + "n" + "欢迎下次光临！------------------------");
	}
}