Main 方法错误地显示类字符串？

Question

我正在编写一个程序，它提供酒店住宿的最终账单，其中包含房间号、客人数量、住宿时间和每人每晚的价格等参数。

我的 BBroom 类中的数学是正确的，但它似乎没有获取和处理类参数中的信息？

驱动类：

public class BedAndBreakfastDriver {

public static void main(String[] args) {

    //float price, int rmNum, int numOccupants, int duration
    //or
    //int rmNum, int numOccupants, int duration, float price

    BBRoom Smith;

    Smith = new BBRoom(29.95, 16, 1, 5);

    System.out.println(Smith);

}

}

BB Room 类：

public class BBRoom {

final int MAXCAP = 4;
final int MINCAP = 1;
final int MINSTAY = 1;

int room;
int persons;
int nights;
double cost;
double surcharge;
double cleanUp;
double cottageCost;

NumberFormat fmt1 = NumberFormat.getCurrencyInstance();

BBRoom(double price, int rmNum, int numOccupants, int duration){}


BBRoom( int rmNum, int numOccupants, int duration, double price){}

       private int getRoomNumber(int rmNum){
           room = rmNum;       
           return room;
       }

       private int getPersons(int numOccupants){
           if (numOccupants < MINCAP){
               persons = MINCAP;
           }if(numOccupants > MAXCAP){
                persons = MAXCAP;
             }else{
               persons = numOccupants;
           }
           return persons;
           }

       private int getNights(int duration){   

           if(duration < MINSTAY){
               nights = MINSTAY;

           }else{

               nights = duration;

           }

           return nights;
       }

       private double setCost(double price){
           return price;

       }
       private double getCost(double price){



         if (persons < 2){
             cost = price*2*nights;
            }else{
             cost = (persons*price*nights);
         }

           return cost;
             }

        private double BBCottage(double cost){

               surcharge =  (12.95*nights);

               cleanUp = 47.99;

               cottageCost = cost+surcharge+cleanUp;

               return cottageCost;

           }

        public String toString(){

               String bill = ("Room Number"+room+"   "+"Guests:"+persons+"   "+"Nights:"+nights+"   "+"Basic Package:"+ fmt1.format(cost)+"   "+"Cottage Upgrade:"+fmt1.format(cottageCost) );
               return bill;
           }

        }

出于某种原因，我不断得到输出以将每个变量显示为

“房间数：0 客人：0 晚：0 基本套餐：0.00 小屋升级：0.00”

任何帮助将不胜感激。谢谢！

附：我也更喜欢将我的 BBCottage 方法变成一个子类，但我不太确定如何实现这一点。如果我也能在这方面得到一些指导，那就太好了！

Answer 1

你的构造函数有一个空的主体

BBRoom(double price, int rmNum, int numOccupants, int duration){} // <<<<<<< nothing going on in {}

所有相关字段都被初始化为其默认值0。实现构造函数来做你想做的事。

Answer 2

您从未真正在 BB Room 中设置值。此外，getVariable(int something) 方法应拆分为单独的 get() 和 set(int something) 方法，否则您将同时获取和设置变量。

在您的 toString 方法中，您调用将从 get() 返回的值，但这些值从未设置。要修复它，您需要在构造函数中设置它们。

Answer 3

您的构造函数需要设置初始值。

BB 房间：

public class BBRoom {

final int MAXCAP = 4;
final int MINCAP = 1;
final int MINSTAY = 1;

int room;
int persons;
int nights;
double cost;
double surcharge;
double cleanUp;
double cottageCost;

NumberFormat fmt1 = NumberFormat.getCurrencyInstance();

BBRoom(double price, int rmNum, int numOccupants, int duration){
   someInstanceVariable = price;
   room = rmNum;
   persons = numOccupants;
   ..and so on..
}


BBRoom( int rmNum, int numOccupants, int duration, double price){
    ..do the same here..
}

       private int getRoomNumber(int rmNum){
           room = rmNum;       
           return room;
       }

       private int getPersons(int numOccupants){
           if (numOccupants < MINCAP){
               persons = MINCAP;
           }if(numOccupants > MAXCAP){
                persons = MAXCAP;
             }else{
               persons = numOccupants;
           }
           return persons;
           }

       private int getNights(int duration){   

           if(duration < MINSTAY){
               nights = MINSTAY;

           }else{

               nights = duration;

           }

           return nights;
       }

       private double setCost(double price){
           return price;

       }
       private double getCost(double price){



         if (persons < 2){
             cost = price*2*nights;
            }else{
             cost = (persons*price*nights);
         }

           return cost;
             }

        private double BBCottage(double cost){

               surcharge =  (12.95*nights);

               cleanUp = 47.99;

               cottageCost = cost+surcharge+cleanUp;

               return cottageCost;

           }

        public String toString(){

               String bill = ("Room Number"+room+"   "+"Guests:"+persons+"   "+"Nights:"+nights+"   "+"Basic Package:"+ fmt1.format(cost)+"   "+"Cottage Upgrade:"+fmt1.format(cottageCost) );
               return bill;
           }

        }

关于将Cottage分成另一个类：

BBCottage：

public class BBCottage {
  public BBCottage(double cost){

           surcharge =  (12.95*nights);

           cleanUp = 47.99;

  }

  public double getCottage() {
     cottageCost = cost+surcharge+cleanUp;

     return cottageCost;
  }
  }

编辑：我还意识到，在您的主要内容中，您正在执行System.out.println(Smith);。您已经打印了方法，而不是 Smith。因此，首先，我将 BBroom 更改为拥有 getter 和 setter：

void setRmNum(int rm) {
    room = rm;
}

int getRmNum() {
    return room;
}

然后，在你的主要，做System.out.println(Smith.getRmNum());