package com.imooc;

public class Car {
    public int rent;
    public String name;
    public  void dis()
    {
        System.out.print("\t\t"+name+"\t\t"+rent+"元/天");
    }

}

package com.imooc;

public class Lperson extends Car {
    public int person;
    public Lperson(String n,int p,int b){
        super.name=n;
        super.rent=p;
        person=b;
    }
    public  void dis()
    {
        super.dis();
        System.out.print("      "+"载人:"+person+"人\n");
    }

}

package com.imooc;

public class Lbags extends Car {
        public int bag;
        public Lbags(String n,int p,int b){
            super.name=n;
            super.rent=p;
            bag=b;
        }
        public  void dis()
        {
            super.dis();
            System.out.print("      "+"载货:"+bag+"吨\n");
        }

}

package com.imooc;

public class Lpb extends Car {
        public int bag;
        public int person;
        public Lpb(String n,int p,int pe,int b){
            super.name=n;
            super.rent=p;
            person=pe;
            bag=b;
        }
        public  void dis()
        {
            super.dis();
            System.out.print("\t载人:"+person+"人  载货："+bag+"吨\n");
        }
}

package com.imooc;
import java.util.*;
public class UI {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Car c[]={new Lperson("奥迪A4",500,4),new Lperson("马自达6",400,4),
                        new Lpb("皮卡雪6 " ,450,4,2),new Lperson("金      龙",800,20),
                        new Lbags("松花江",400,4),new Lbags("依维柯",1000,20)};
        System.out.println("欢迎使用答答租车系统:");
        System.out.println("您是否要租车:1.是 2.否");
        Scanner input=new Scanner(System.in);
        int Choice=input.nextInt();
        if(Choice==1){
            System.out.println("您可租车类型及其价目表:");
            System.out.println("序号\t\t汽车名称\t\t租金\t\t\t容量");
            for(int i=1;i<=6;i++)
            {
                System.out.print(i);
                c[i-1].dis();
            }
        System.out.println("请输入您要租车的数量:");
        int Number=input.nextInt();
        int a[]=new int[Number];
        int j;
        for(int i=0;i<Number;i++)
        {
                j=i+1;
                System.out.println("请输入第"+j+"辆车的序号:");
                a[i]=input.nextInt();
        }
            System.out.println("请输入租车天数:");
            int Day=input.nextInt();
            int sum=0;
            int person=0;
            int bag=0;
            System.out.println("您的账单:");
            System.out.println("***可载人的车有:");
            for(int n=0;n<Number;n++)
            {
                if(a[n]==1a[n]==2a[n]==3a[n]==4)
                    {
                        System.out.print(c[a[n]-1].name+"\t\t");    
                        if(c[a[n]-1] instanceof Lperson)
                            person+=((Lperson)c[a[n]-1]).person;
                        else if(c[a[n]-1] instanceof Lpb)
                            person+=((Lpb)c[a[n]-1]).person;
                        sum+= Day*c[a[n]-1].rent;
                    }
            }
            System.out.print("\n共载人:"+person+"人");
            System.out.println("\n***可载货的车有:");
            for(int n=0;n<Number;n++)
            {   
                if(a[n]==3a[n]==5a[n]==6)
                {
                    System.out.print(c[a[n]-1].name+"\t");  
                    if(c[a[n]-1] instanceof Lbags)
                        {
                            bag+=((Lbags)c[a[n]-1]).bag;
                            sum+= Day*c[a[n]-1].rent;
            //作为既能载客又能载货的，上面载客已经算过价格了
                        }
                    else if(c[a[n]-1] instanceof Lpb)
                        bag+=((Lpb)c[a[n]-1]).bag;
                }
            }
            System.out.print("\n共载货:"+bag+"吨");     
            System.out.println("\n***租车总价格:"+sum+"元");
        }   
        else 
            System.out.println("系统已结束！");
    }
}

1.用了if来作为操作的选择，只能操作一次，用while可以实现循环操作；
2.出现了父类到子类的强制类型转换，要注意溢出问题；
3.两次统计载客的车，载货的车都用了for循环遍历了所有的，增加了程序的时间复杂度，不是很好；