Simple Seat Reservation in Java

Question

package Demo;

import java.util.Scanner;

public class seat_reservation{

    public static void main(String[] args) {

        Scanner read = new Scanner(System.in);

        // Initialization

        final int ROWS = 2;
        final int COLS = 3;

        char [][] seats = new char [ROWS][COLS];
        int i, j, seatNum, counter = 0;
        char seatLetter = 'A';
        int choice = 0;
        String seatEnter;
        boolean cont = true; // loops of running the program

        while( choice != 4 ){

            System.out.print( "1. Assign Seats"      );
            System.out.print( "2. Exit"              );
            System.out.print( "Select your choice: " );

            choice = read.nextInt();

            switch( choice ){

                case 1:
                    //Set the value.
                    for (i=0; i < seats.length; i++) {

                        for (j=0; j < seats[i].length; j++)
                            seats[i][j] = seatLetter++;

                        seatLetter = 'A'; // to reset the value to A for the new loop
                    }

                    //To display the list of seats

                    for (i=0; i < seats.length; i++) {
                        System.out.print((i+1)+" ");

                        for (j=0; j < seats[i].length; j++)
                            System.out.print(seats[i][j]+" ");

                        System.out.println();
                    }

                    //condition
                    while (counter < 6 && cont) {
                        do {

                            System.out.print("Please type the chosen seat(starts with row and column,e.g:2A):" + "");

                            seatEnter = (read.nextLine()).toUpperCase(); //covert to Upper case
                            seatNum   = Integer.parseInt(seatEnter.charAt(0)+"");

                            if (seatNum != 0)
                                seatLetter = seatEnter.charAt(1);

                            i++;

                            //if user enters wrong input, error message will appear.

                            if (seatLetter!='A'){
                                if (seatLetter!='B'){
                                    if(seatLetter!='C'){
                                        if(seatLetter!='D')
                                            System.out.println ("Invalid! Please enter the correct seat:");
                                    }
                                }
                            }
                        }

                        //continue to loop until the condition true
                        while (seatNum < 0 || seatNum > 7 || seatLetter < 'A' || seatLetter > 'D');

                        if (seatNum == 0) {
                            cont = false;
                        } else {
                            if (seats[seatNum-1][seatLetter-65] == 'X')
                                System.out.println("Seat have been taken.Please choose another seat:");
                            else {
                                seats[seatNum -1][seatLetter-65] = 'X';

                                counter++;
                            }

                            // To display updated lists of seats
                            for (i=0; i < seats.length; i++) {
                                System.out.print((i+1)+" ");

                                for (j=0; j < seats[i].length; j++)
                                    System.out.print(seats[i][j] + " ");

                                System.out.println();
                            }

                            System.out.println(" ") ;

                            //}
                            //}
                            // displays fully booked message
                            if (counter == 6)
                                System.out.println("All seats are now fully-booked.");
                            break;
                        }
                    }

                case 2://syntax error here
                    if (counter == 6)
                        System.out.println( "All seats are now fully-booked." );
                        System.out.println( "End of Program"                  );

                        System.exit(0);
                        break;

                default:
                    System.out.println("Error input"); 
                    break;//syntax error here as well.

            }
        }
    }
}

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This code is a mess. Please make sure you are using the `code` option (or indent by at least 4 spaces) and make sure that you aren't missing and brackets for your loops, it is really hard to tell which elements are supposed to be in which loops — ConnerWithAnE, Aug 11 '21 at 05:09
This is caused by the issue described at https://stackoverflow.com/q/13102045 — Dawood ibn Kareem, Aug 11 '21 at 05:17

devReddit · Answer 1 · 2021-08-11T15:05:07.207

The problem is caused due to:

choice = read.nextInt();

The scanner.nextInt() only takes the next token from the input. Rest are ignored by it.

So when you're trying to take the next input from this line and process it, the error occurs:

seatEnter = (read.nextLine()).toUpperCase(); //covert to Upper case
seatNum = Integer.parseInt(seatEnter.charAt(0) + "");

As the previous read.nextInt() left the rest except first token, when you hit enter after giving 1 as input, it took only the 1 and the enter or newline token was captured by the read.nextLine(). That is why it got no charAt(0) and thus thrown StringIndexOutOfBoundException.

Try:

choice = Integer.parseInt(read.nextLine());

or,

choice = read.nextInt();
read.nextLine();                       // this will capture the residue

Simple Seat Reservation in Java

1 Answers1