达达租车 写的不好 请大家帮忙看看

package dada;
import java.util.Scanner;
public class zuche {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    System.out.println("欢迎使用答答租车系统");  
    System.out.println("您是否要租车：1是 0否");
    Scanner input=new Scanner(System.in);
     int num=input.nextInt();
     if(num==1){
         System.out.println("");
     }else{
         return;//退出
     }
     car car1=new keche("奥迪A4");  
     car car2=new keche("马自达6");
     car car3=new pika("皮卡雪6");
     car car4=new keche("金龙");
     car car5=new kache("松花江");
     car car6=new kache("依维柯");
     String cars[] = {"奥迪A4","马自达6","皮卡雪6","金龙","松花江","依维柯"};
     int huo[] = {0,0,2,0,4,20,};//将载货数输入数组
     int ren[] = {4,4,4,20,0,0};//将载人数输入数组
     int money[] = {500,400,450,800,400,1000};
     System.out.println("您可租车的类型及价目表：");      
     System.out.println("序号 汽车名称 租金    容量");
     System.out.println("1. 奥迪A4 500元/天 载人：4人");
     System.out.println("2. 马自达6 400元/天 载人：4人");
     System.out.println("3. 皮卡雪6 450元/天 载人：4人，载货：2吨");
     System.out.println("4. 金龙 800元/天 载人：20人");
     System.out.println("5. 松花江 400元/天 载货：4吨");
     System.out.println("6. 依维柯 1000元/天 载货：20吨");
     System.out.println("请输入您租车的数量");
     int cheshu=input.nextInt();
     int $ =0 ;
     for(int i=1;i<cheshu+1;i++){
          System.out.println("请输入第"+i+"辆车的序号"); 
          int xuhao=input.nextInt();
          System.out.println("第"+i+"辆车的名称是");
          System.out.println(cars[xuhao-1]);
          System.out.println("第"+i+"辆车的载人数");
          System.out.println(ren[xuhao-1]);
          System.out.println("第"+i+"辆车的载货数");
          System.out.println(huo[xuhao-1]);
           $ = $ + money[xuhao-1];
          }
    System.out.println("请输入您租车的天数");
     int tian=input.nextInt();
     System.out.println("您的总租金为");
     System.out.println($*tian);
     }
}

package dada;

public class pika extends car {
public pika(String name) {
super(name);
this.name =name;

}

}

package dada;

public class keche extends car {
public keche(String name) {
super(name);
this.name =name;

}

}

package dada;

public class kache extends car {
public kache(String name) {
super(name);
this.name =name;

}

}

package dada;
public class car {
public String name;//车名
public car(String name) {
this.name =name;

}

}