这个照着打的怎么输出的没有数组中的值啊？
package com.xml.rentcar;
//父类
public class Car {
private int num;//数量
private String name;//车名
private int rent;//租金
private int manned;//载货
private int burden;//容量
public Car(int num, String name, int rent, int manned, int burden) {
this.num = num;
this.name = name;
this.rent = rent;
this.manned = manned;
this.burden = burden;
}
public Car(){
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getRent() {
return rent;
}
public void setRent(int rent) {
this.rent = rent;
}
public int getManned() {
return manned;
}
public void setManned(int manned) {
this.manned = manned;
}
public int getBurden() {
return burden;
}
public void setBurden(int burden) {
this.burden = burden;
}
}-----------------------
package com.xml.rentcar;
/*
* 载人的子类
*/
public class MannedCar extends Car {
private int manned;
public int getManned() {
return manned;
}
public void setManned(int manned) {
this.manned = manned;
}
public MannedCar(int manned,String name,int rent,int num) {
this.manned = manned;
}
}
-----------------------
package com.xml.rentcar;
/*
* 载货的子类
*/
public class BurdenCar extends Car {
private int burden;
public int getBurden() {
return burden;
}
public void setBurden(int burden) {
this.burden = burden;
}
public BurdenCar(int num,String name,int rent,int burden) {
this.burden = burden;
}
}
-------------
package com.xml.rentcar;
/*
* 既有载人也有载货的子类
*/
public class BothCar extends Car {
private int manned;
private int burden;
public int getManned() {
return manned;
}
public void setManned(int manned) {
this.manned = manned;
}
public int getBurden() {
return burden;
}
public void setBurden(int burden) {
this.burden = burden;
}
public BothCar(int num,String name,int rent,int manned, int burden) {
this.manned = manned;
this.burden = burden;
}
}
----------------
package com.xml.rentcar;
import java.util.Scanner;
public class Main {
public static Scanner sc = new Scanner(System.in);
public static void main(String[] args) {
System.out.println("欢迎来到涛涛租车系统：");
System.out.println("你是否要租车呀？1是，0否");
sc = new Scanner(System.in);
int a = sc.nextInt();
if(a==1){
System.out.println("你可以租车的类型及价目表");
System.out.println("序号 汽车名称 租金 容量");
Car[] types = { new MannedCar(1, "奥迪A4", 500, 4),
new MannedCar(2, "马自达", 400, 4),
new MannedCar(3, "上海大众", 600, 3),
new MannedCar(4, "吉利自由舰", 200, 5),
new MannedCar(5, "凯迪拉克", 600, 4) };
for (Car car : types) {
if(car instanceof MannedCar){
System.out.println(car.getNum()+"\t"+car.getName()+"\t"+car.getRent()+"\t"+"载人"+car.getBurden());
}
else if(car instanceof BurdenCar){
System.out.println(car.getNum()+"\t"+car.getName()+"\t"+car.getRent()+"\t"+"载货"+car.getBurden());
}
else {
System.out.println(car.getNum()+"\t"+car.getName()+"\t"+car.getRent()+"\t"+"载人："+car.getManned()+"\t"+"载货"+car.getBurden());
}
}
System.out.println("请输入你要租车的数量：");
sc = new Scanner(System.in);
int num = sc.nextInt();
while(num<0){
System.out.println("你输入有误，请重新输入");
num = sc.nextInt();
}
double rentSum = 0;
int mannedSum = 0;
double burdenSum = 0;
for(int j =1 ;j<=num ;j++){
System.out.println("请选择第"+j+"辆车");
sc = new Scanner(System.in);
int num2 = sc.nextInt();
while(num2<=0&&num2>types.length){
System.out.println("你输入的有误！！请重新输入");
num2 = sc.nextInt();
}
if(types[num2-1] instanceof MannedCar){
System.out.println("你选择了" + types[num2 - 1].getName()
+ "\t" + "租金为每天" + types[num2 - 1].getRent() + "元"
+ "\t" + "载客量为" + types[num2 - 1].getBurden());
}
else if(types[num2-1] instanceof BurdenCar){
System.out.println("您选择了" + types[num2 - 1].getName()
+ "\t" + "租金为每天" + types[num2 - 1].getRent() + "元"
+ "\t" + "载客量为" + types[num2 - 1].getManned()
+ "\t" + "载货量为" + types[num2 - 1].getBurden());
}
else{
System.out.println("您选择了" + types[num2 - 1].getName()
+ "\t" + "租金为每天" + types[num2 - 1].getRent() + "元"
+ "\t" + "载客量为" + types[num2 - 1].getManned()
+ "\t" + "载货量为" + types[num2 - 1].getBurden());
}
rentSum = rentSum+types[num2-1].getRent();
mannedSum = mannedSum+types[num2-1].getManned();
burdenSum =burdenSum+types[num2-1].getBurden();
}
System.out.println("你的账单是:");
System.out.println("*****总载客量为："+mannedSum+"人");
System.out.println("*****总载货量为："+burdenSum+"吨");
System.out.println("*****总共需要："+rentSum+"元");
}
else if(a==0){
System.out.println("谢谢你的使用！系统将自动退出");
}else{
System.out.println("你输入的有误！系统将自动退出");
}
}
}
--------------
输出结果：
欢迎来到涛涛租车系统：
你是否要租车呀？1是，0否
1
你可以租车的类型及价目表
序号 汽车名称 租金 容量
0 null 0 载人0
0 null 0 载人0
0 null 0 载人0
0 null 0 载人0
0 null 0 载人0
请输入你要租车的数量：
1
请选择第1辆车
1
你选择了null 租金为每天0元 载客量为0
你的账单是:
*****总载客量为：1人
*****总载货量为：0.0吨
*****总共需要：0.0元
Bobzhangxiaotao2回答
-
MengFly
你在初始化car的子类里面没有显示调用父类的方法，所以它会默认调用父类不带参数的构造方法，这样的话就不会对父类里面的变量进行初始化了，如果你想初始化父类里面的变量应该在子类里面显示调用父类的带参数的构造方法。 -
Bobzhangxiaotao
已解决是的
随时随地看视频慕课网APP
相关分类
Java