Question

Labs

CSIT 210 Introduction to Programming

LAB 9B Arrays

Change the program AirlineDriver.java to assign passenger seats in an airplane.

Chesapeake Airlines is a small commuter airline with seats for 20 passengers in 5 rows of 4 seats each. Here is the layout:

1ABCD 2ABCD 3ABCD 4ABCD 5ABCD

The user enters the row (1 – 5) and the seat (A – D). The seat entry may be lowercase.

Use this code to enter the seat:

System.out.print(" Enter row and seat "); seat = scan.nextLine();

r = seat.?? c = seat.??

What will you need to do to change r to a valid row index?

What will you need to do to change the character (A, B, C, D) in the variable c to the column index in the array? Check the program example on page 347. I have included the LetterCount program in the Chapter Seven Activities.

The program checks the array to see if the seat is available. An X in the array indicates the seat is not available.

If the seat is available, assign an X to that position in the array. If it’s unavailable, display a message to the passenger. Use the displaySeats method after each row/seat entry.

After some seats are assigned, the layout may look like this:

1XBCX 2ABCD 3AXCX 4ABCD 5ABCD

1

Labs

CSIT 210 Introduction to Programming

Continue processing requests until the user enters -1 for seat.

2

Answer 1

JAVA PROGRAM:

package test.airline;

import java.util.Scanner;

public class AirlineDriver {
   private static final int ROW_COUNT = 5;
   private static final int SEAT_COUNT_PER_ROW = 4;
   private String[][] passengerSeats = null;
  
   //INITILIZES THE COBSTRUCTOR WITH ARRAY
   public AirlineDriver(){
       passengerSeats = new String[ROW_COUNT][SEAT_COUNT_PER_ROW];
      
       for(int i = 0; i< ROW_COUNT; i++){
           passengerSeats[i] = new String[]{"A","B","C","D"};
       }
   }

   public static void main(String[] args){
       AirlineDriver ad = new AirlineDriver();
       String seat = null;
       String row = null;
       Scanner scan = new Scanner(System.in);
       boolean isContinue = true;
      
       while(isContinue){ //CONTINUE LOOPING
           System.out.println("Enter row and seat"); // ENTER ROW AND SEAT NUMBER FROM USER
           row = scan.next();
           seat = scan.next();
          
           int r = Integer.parseInt(row) -1; // User will enter between 1 to 5
           //however to make it proper array index I have subtracted 1 from it to make it zero based
           String c = null;
           if(!seat.equals("-1")){//if user enters -1 for the seat the while lop will terminate
               if(seat.length()==1 && Character.isLowerCase(seat.charAt(0))){
                   c = seat.toUpperCase();
               }
              
               boolean isAvailable = false;
               for(int i = 0 ; i < SEAT_COUNT_PER_ROW; i++){
                   if(!ad.passengerSeats[r][i].equals("X") && c.equals(ad.passengerSeats[r][i])){ //the seat is available and matches with user requested seat
                       ad.passengerSeats[r][i] = "X";//mark the seat as occupied with X
                       isAvailable = true;
                       break;//break out of the loop
                   }
               }
              
               if(!isAvailable){ //if not available show message
                   System.out.println("The seat is not available right now.");
               }
              
               ad.display(ad.passengerSeats);// display passenger seat situation
           }else{
               isContinue = false;
           }
          
          
       }
      
      
   }
  
  
   private void display(String[][] passengersSeat){
       StringBuilder str = new StringBuilder();
       for(int i = 0; i< passengersSeat.length;i++){
           str.append(i+1).append(String.join("",passengersSeat[i]));
           str.append(" ");
       }
      
       System.out.println(str.toString());
   }
  

}

OUTPUT

Enter row and seat
1 a
1XBCD 2ABCD 3ABCD 4ABCD 5ABCD
Enter row and seat
2 b
1XBCD 2AXCD 3ABCD 4ABCD 5ABCD
Enter row and seat
3 c
1XBCD 2AXCD 3ABXD 4ABCD 5ABCD
Enter row and seat
4 d
1XBCD 2AXCD 3ABXD 4ABCX 5ABCD
Enter row and seat
2 b
The seat is not available right now.
1XBCD 2AXCD 3ABXD 4ABCX 5ABCD
Enter row and seat
3 -1

EXPLANATION:

COMMENTS GIVEN within the code.