如何只打印数组中的一些对象？

Question

我正在为我的 CSCI 课做作业，但遇到了一个障碍。

在我们的作业中，我们创建了一个乘客类，然后是我们的航班代码。

我们的 Flight 是从一个文本文件中读取前 20 个人，然后将它们分配到我们数组对象中的一个位置。输入这 20 人后，其余乘客（21-55）将由用户通过对话框插入。

我已经完成了所有这些，但是在此之后，我们需要根据他们拥有的航班舱位打印出我们数组中的每个人，即打印所有头等舱的人，然后是商务舱，然后是经济舱。当我尝试打印我的所有对象时，只打印我的文本文件中的人，而不是用户输入的每个人。

这是我的代码

    import javax.swing.JOptionPane;
import java.io.*;

import java.util.Scanner;

public class Flight_EdgarFlores
    { 
      public static void main(String[] args) throws IOException
      {
        String fullName=null;
        String seatClass=null;
        String seatNumber=null;
        String ff_Number=null;
        String points=null;
        String line, word;
        int seat_Choice, again;

        Passengers[] Pass; 
    final int NUM_OF_PASSENGERS= 55;  //size of array
    Pass = new Passengers[NUM_OF_PASSENGERS];

    Scanner  lineScan;
    Scanner fileScan = new Scanner(new File("PassengerList.txt"));

    int line_counter = 0;
    int word_counter = 0;

    while(fileScan.hasNext())
    {
      line = fileScan.nextLine(); 

      lineScan = new Scanner(line);   // Scans each line of the file
      lineScan.useDelimiter(", ");

      word_counter = 0;
      while(lineScan.hasNext())  // Reads each word in the line 
      {

        word = lineScan.next();
        switch (word_counter)
        {
          case 0:
            fullName = word;
            break;  
          case 1:
            seatClass = word;
            break;
          case 2:
            seatNumber = word;
            break;
          case 3:
            ff_Number = word;
            break;
          case 4:
            points = word; 
            break;
          }
        word_counter++;
      }  
      if(word_counter==3)
        Pass[line_counter] = new Passengers(fullName, seatClass, seatNumber);

      if(word_counter==5)
       Pass[line_counter] = new Passengers(fullName, seatClass, seatNumber, ff_Number, points);

        line_counter++;
    }
    int counter=20;
    do
    {
      String full_Name = JOptionPane.showInputDialog("Enter Full Name: ");

      String[] seatClassChoice = new String[3];
      seatClassChoice[2] = "Economy Class";
      seatClassChoice[1] = "Business Class";
      seatClassChoice[0] = "First Class";

      int classChoice = JOptionPane.showOptionDialog(null, "Choose Seat Class", "Seat Class Choice", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, seatClassChoice, seatClassChoice[0]); 
      if(classChoice==0)
      {
        String[] seatChoice = {"1A", "2A", "3A", "4A", "5A", "6A"};
        seat_Choice = JOptionPane.showOptionDialog(null, "Choose Seat ", "Seat Choice", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, seatChoice, seatChoice[0]); 
      }
      else if(classChoice==1)
      {
        String[] seatChoice = {"7A", "7B", "8A", "8B", "9A", "9B", "10A", "10B", "11A", "11B"};
        seat_Choice = JOptionPane.showOptionDialog(null, "Choose Seat ", "Seat Choice", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, seatChoice, seatChoice[0]);
      }
      else if(classChoice==2)
      {
        String[] seatChoice = {"12A", "12B", "12C", "13A", "13B", "13C", "14A", "14B", "14C", "15A", "15B", "15C", "16A", "16B", "16C", "17A", "17B", "17C", "18A", "18B", "18C", "19A", "19B", "19C", "20A", "20B", "20C", "21A", "21B", "21C", "22A", "22B", "22C", "23A", "23B", "23C", "24A", "24B", "24C" };
        seat_Choice = JOptionPane.showOptionDialog(null, "Choose Seat ", "Seat Choice", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, seatChoice, seatChoice[0]);
      }
      Pass[counter] = new Passengers(full_Name, seatClass, seatNumber);
      again = JOptionPane.showConfirmDialog(null, "Add another Passenger?");
      counter++;
    }while((counter<NUM_OF_PASSENGERS)&& (again==JOptionPane.YES_OPTION));

    Pass[0].addFrequentFlyer("#2AZ433", "4455"); //adds flyer number and flyer points to object at index 0

    for(int i=0; i<NUM_OF_PASSENGERS; i++)
    {
      if(Pass[i].getseatClass().equals("First Class"))
      System.out.println(Pass[i] + " , " + i);

    }
    for(int i=0; i<=NUM_OF_PASSENGERS; i++)
    {
      if(Pass[i].getseatClass().equals("Business Class"))
      System.out.println(Pass[i] + " , " + i);
    }
    for(int i=0; i<=NUM_OF_PASSENGERS; i++)
    {
      if(Pass[i].getseatClass().equals("Economy Class"))
      System.out.println(Pass[i] + " , " + i);
    }

    }
}

这是我的乘客舱

public class Passengers
{
  private String fullName, seatClass, seatNumber, frequentFlyerNumber, flyerPoints;

  public Passengers (String full_name, String seat_class, String seat_number, String frequent_flyernumber, String flyer_points)
  {
    fullName=full_name;
    seatClass=seat_class;
    seatNumber=seat_number;
    frequentFlyerNumber=frequent_flyernumber;
    flyerPoints=flyer_points;
  }
  public Passengers (String full_name, String seat_class, String seat_number)
  {
    fullName=full_name;
    seatClass=seat_class;
    seatNumber=seat_number;
  }

  public void addFrequentFlyer (String frequent_flyer_number, String flyer_Points)
  {
    frequentFlyerNumber=frequent_flyer_number;
    flyerPoints=flyer_Points;
  }

 /* public String getLastName()
  {
    String lastName="";
    int nameLength= fullName.length();
    for(int i =nameLength; i> 0; i--)
    {
      if(full_name.charAt(i)!=' ')
        lastName+=fullName.charAt(i);
      else
        break;
    }
   }*/

  public String getseatClass()
  {
    return seatClass;
  }
  public String toString()
  {
    return fullName + ", "+ seatClass + ", " + seatNumber;
  }
}

Answer 1

我的猜测是您抛出了一个数组越界异常，因为您正在 for 循环中为 Business 和 Economy 乘客执行以下检查

for(int i=0; i<=NUM_OF_PASSENGERS; i++)...

但是对于您的头等舱乘客，您可以这样做

for(int i=0; i<NUM_OF_PASSENGERS; i++)...

由于您正在执行 i