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\t\t" + "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！------------------------");

}

}

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