A full of bugs, unoptimized Java code for a CLI airline reservation.. Everything was built to be static. You may make it better or use the methods elsewhere.

AirlineRes.java

package airlinereservationsystem_yawboakyeyiadom;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.InputMismatchException;
import java.util.Scanner;

/**
 * 
 * @author yaw
 */

public class AirlineReservation {

	/**
	 * @param args
	 */
	private static Scanner sc = new Scanner(System.in);
	private static boolean changesMadeToFile = false;
	
	//all the seats in the aero plane
	private static String[][] seats = new String[70][8];
	private static String destination = null;
	
	private static String[] seat = null;
	private static double[] ticketPrices = new double[2];
	private static double total;
	private static String firstname = null;
	private static String lastname = null;
	private static int age = 0;
	

	//the directory containing all the files
	private static String parent = "src/airlinereservationsystem_yawboakyeyiadom/files/";
	
	public static void main(String[] args) {
		
		String emptySeats = null;
		boolean seatsAvailable = false;
		String[][] noFly = new String[31][2];
		
		while(true) {
			System.out.println("Welcome to the Airline Reservation System!\n");
			System.out.print("Are you a customer or a gate agent? ");
			
			String clientType = sc.next();
			String oldDestination = destination;
			
			try {
				getTicketPrices();
				destination = getRoute(clientType);
			} catch (InputMismatchException ex) {
				System.out.println("\nThe route you chose does not exist.\n");
				if(tryAgain()) {
					continue;
				} else {
					//sc.close();
					System.exit(0);
				}
				
			} catch (IOException e) {
				System.out.println();
			} catch (Exception ex) {
				if(tryAgain()) {
					continue;
				}
				System.exit(0);
			}
			
			//at this point in execution, read the file just once for the mean time. Another read is only required
			//if the destination (route) is changed e.g. change of route of ACC to KUM to ACC to TAM. if this isn't the
			//initial run of the program, check to see if reservations were made in the former route and take appropriate
			//actions
			if(destination != null && !(destination.equals(oldDestination))) {
				if(changesMadeToFile) {
					saveToFile(oldDestination);
					changesMadeToFile = false;
				}
				
				try {
					populateFlightDatabase(destination, seats); //read from a file and save in the seats array
					emptySeats = emptySeatsAvailable(seats);
					seatsAvailable = emptySeats.length() > 0;
					
				} catch (IOException e) {
					//reading file content into RAM failed...
					//aero plane is empty and waiting for reservations
					System.err.println("Sorry. I think this plane is not ready for boarding yet because I couldn't\n" +
							"get a list of all the reservations already made. Come again in about 30 minutes time. " +
							"Thank you");
					System.exit(0);
					
					
				}
			}
			
			if(isAnswer("customer", clientType) || isAnswer("gate agent", clientType) || isAnswer("agent", clientType)) {
				if(changesMadeToFile) {
					saveToFile(destination);
				}
				System.out.printf("\nYou are now in the %s menu. What will you like to do for today?\n", getRouteName());
			}
			
			if(isAnswer("customer", clientType)) {
				//get customer's choice of service
				String customerChoice = customerMenu();
				
				switch(customerChoice) {
					case "1":
						if(seatsAvailable) {
							printAvailableSeats(seats);
						} else {
							//there are no empty seats :(
							System.out.println("There are no seats available on this flight. Thank you.");
						}
						break;
					case "2":
						if(seatsAvailable) {
							makeReservation(seats);
						} else {
							//there are no empty seats. No reservations can be made :(
							System.out.println("There are no seats available on this flight. Thank you.");
						}
						break;
					case "3":
						printBoardingPass();
						break;
					case "4":
						printReceipt();
						break;
					case "5":
					try {
						changeSeatAssignment();
					} catch (Exception e) {
						System.out.println("\nDear customer, an error encountered prevented your change of seat.\n");
					}
						break;
					default:
						System.out.println("\nThe option you chose is not available on the menu.\n");
				}
				
				System.out.println(); //create a blank line between consecutive transactions
				
			} else if(isAnswer("agent", clientType) || isAnswer("gate agent", clientType)) {
				//client is a gate agent
				String agentChoice = agentMenu();
				
				switch(agentChoice) {
					case "1":
						checkNoFlyList(noFly);
						break;
					case "2":
						performUpgrade();
						break;
					case "3":
						printPassengerRoster();
						break;
					case "4":
						printSalesReport();
						break;
					default:
						System.out.println("\nYour choice is not available on the menu. " +
								"Please choose an option on the menu.\n");
				}
				
			}
			
			if(tryAgain()) {
				continue;
			}
			
			break;
		}
	}

	private static void printSalesReport() {
		double firstClassSales = 0.0, economyClassSales = 0.0;
		for(String[] s : seats) {
			if(!isEmpty(s)) {
				if(s[7].equalsIgnoreCase("first")) {
					firstClassSales += ticketPrices[1];
				} else if(s[7].equalsIgnoreCase("economy")) {
					economyClassSales += ticketPrices[0];
				}
			}
		}
		
		System.out.printf(
				"\nTOTAL TICKET SALES FOR ACC to %s\n" +
				"---------------------------------\n" +
				"%-12s : %.2f GHc\n" +
				"%-12s : %.2f GHc\n\n" +
				"%-12s : %.2f GHc\n" +
				"---------------------------------\n\n",
				
				getRouteName(), "First Class", firstClassSales, "Economy", economyClassSales,
				"Total", firstClassSales + economyClassSales
			);
	}

	private static void printPassengerRoster() {
		System.out.printf(
				"\nPassenger roster for ACC to %s\n" +
				"-------------------------------\n",
				getRouteName()
			);
		
		System.out.printf(
				"\n%-3s\t| %-3s\t| %-20s\t| %-20s\t| %-3s\t| %s\t| %s\t| %s\n\n",
				"row", "seat", "first", "last", "age", "exit row flag", "seat position", "ticket class"
			);
		
		for(String[] passenger : seats) {
			System.out.printf(
					"%-3s\t| %-3s\t| %-15s\t| %-15s\t| %-3s\t| %-6s\t| %-7s\t| %s",
					passenger[0], passenger[1], passenger[2], passenger[3], passenger[4], passenger[5],
					passenger[6], passenger[7]
				);
			System.out.println();
		}
		
		System.out.println();
	}

	private static void performUpgrade() {
		//check all empty seats available in the first class..
		//if there's none available, exit the operation. No upgrade can be performed
		String[] emptyFirstClassSeats = getClassEmptySeats("first");
		if(emptyFirstClassSeats == null) {
			System.out.println("\nThere are no available seats for upgrade.\n");
			return;
		}
		
		Scanner u_input = new Scanner(System.in);
		System.out.print("Please enter passenger last name: ");
		String[] foundPassenger = findPassengerByLastName(u_input.nextLine());
		if(foundPassenger != null) {
			String firstname = foundPassenger[2];
			String lastname = foundPassenger[3];
			
			if(foundPassenger[7].equalsIgnoreCase("first")) {
				System.out.println("\nUpgrade can be performed for customers in economy class only.\n");
				return;
				
			}
			
			System.out.printf("\n%s %s is currently sitting in %s.\n\n", 
					firstname, lastname, foundPassenger[0]+foundPassenger[1].toUpperCase());
			System.out.println("Here are available first class seats:\n");
			displaySeats(emptyFirstClassSeats);
			System.out.println();
			System.out.print("Please select an available seat to upgrade: ");
			String newSeat = u_input.next();
			
			String[] seatLabel = seatLabelParts(newSeat);
			
			if(belongsToFirstClass(newSeat)) {
				if(swapSeat(seatLabel, foundPassenger)) {
					System.out.printf(
							"Upgrade successful.\n\n" +
							"%s %s is currently sitting in %s\n\n",
							firstname, lastname, seatLabel[0]+seatLabel[1].toUpperCase()
						);
					
					changesMadeToFile = true;
					return;
				}
				
				System.out.println("\nThe seat you chose to upgrade to has already been reserved.\n");
				return;
				
			} else {
				System.out.println("\nThe seat you chose is not available in the first class\n");
				return;
			}
			
		} else {
			//no passenger to upgrade
		}
	}

	private static boolean belongsToFirstClass(String newSeat) {
		String[] s = seatLabelParts(newSeat);
		int row = convertToInt(s[0]);
		if(row >= 1 && row <= 5)
			return true;
		return false;
	}

	private static void checkNoFlyList(String[][] noFly) {
		boolean terroristFound = false;
		if(noFly[0][0] == null) {
			try {
				Scanner noFlyReader = new Scanner(new File(parent + "noFly.csv"));
				noFlyReader.nextLine();
				int index = 0;
				while(noFlyReader.hasNextLine()) {
					noFly[index] = noFlyReader.nextLine().split(",");
					index++;
				}
				
			} catch (FileNotFoundException e) {
				System.out.println("\nNo no-fly list included in the system.\n");
				return;
			}
		}
		
		System.out.println();
		for(String[] terrorist : noFly) {
			for(String[] passenger : seats) {
				if(terrorist[0].equalsIgnoreCase(passenger[2]) && terrorist[1].equalsIgnoreCase(passenger[3])) {
					System.out.printf(
							"%s %s (seat: %s) is on the \"no fly\" list.\n",
							passenger[2], passenger[3], passenger[0]+passenger[1].toUpperCase()
					);
					terroristFound = true;
				}
			}
		}
		
		System.out.println();
		if(!terroristFound) {
			System.out.println("None of the passengers aboard this flight is on the no fly list.\n");
		}
		
		return;
	}

	private static boolean tryAgain() {
		System.out.print("Would you like to perform another transaction (yes/no)? ");
		
		if(!isAnswer("yes", sc.next())) { 
			if(changesMadeToFile)
				saveToFile(destination);
			System.out.println("\nThank you for using Airline Reservation System! Good bye!");
			return false; 
		}
		
		System.out.println(); //create a blank line between consecutive transactions
		return true;
	}

	private static void getTicketPrices() throws IOException {
		Scanner tickets = new Scanner(new File(parent+"ticketPrices.csv"));
		tickets.nextLine(); //read away the headers
		String[] prices = tickets.nextLine().split(",");
		for (int i = 0; i < 2; i++) {
			ticketPrices[i] = Double.valueOf(prices[i]);
		}
		
		tickets.close();
	}

	private static Object getRouteName() {
		String routeName = null;
		switch(destination) {
		case "kumasi":
			routeName = "KUM";
			break;
		case "tamale":
			routeName = "TAM";
			break;
		case "takoradi":
			routeName = "TAK";
			break;
		}
		
		return routeName;
	}

	private static void changeSeatAssignment() {
		//change the seat reservation of a customer. Customers can only move to
		//empty seats in their classes
		Scanner u_input = new Scanner(System.in);
		System.out.print("Please enter your last name: ");
		String[] foundPassenger = findPassengerByLastName(u_input.nextLine());
		if(foundPassenger != null) {
			String[] emptySeats = getClassEmptySeats(foundPassenger[7]);
			
			if(emptySeats != null) {
				System.out.printf("\n" +
						"Hello, %s %s - you are seated in %s in %s class.\n\n" +
						"Here is the list of available %s seats:\n\n",
						foundPassenger[2], foundPassenger[3], foundPassenger[0]+foundPassenger[1].toUpperCase(),
						foundPassenger[7], foundPassenger[7]
					);
				
				displaySeats(emptySeats);
				System.out.println();
				
				System.out.print("Please enter the seat number you wish to move to: ");
				String[] seat = seatLabelParts(u_input.nextLine());
				
				if(swapSeat(seat, foundPassenger)) {
					System.out.printf(
							"Seat change successful.\n\n" +
							"You are now seated in %s.", seat[0]+seat[1].toUpperCase()
						);
					System.out.println("\nYou have successfully changed your seat.\n");
					changesMadeToFile = true;
				} else {
					System.out.println("\nYour seat change could not be carried out successfully.\n");
				}
				
			} else {
				//there are no empty seats for the user to move into
				System.out.println("\nAll the seats in your compartment/class have been reserved.\n");
			}
		} else {
			
			System.out.println("\nPassenger not found\n");
//			return;
		}
	}

	private static void displaySeats(String[] emptySeats) {
		for(String s : emptySeats) {
			int labelSize = s.length()-1;
			String seatLetter = s.substring(labelSize);
			int row = convertToInt(s.substring(0, labelSize));
			
			String position = (seatLetter.equals("A") || seatLetter.equals("D")) ? "window" : "aisle";
			System.out.printf("%s (%s)", s, position);
			System.out.printf((row >= 10 && row <= 13) ? " - emergency exit\n" : "\n");
		}
	}

	private static boolean seatReallyEmpty(String[] seat) {
		int stop = convertToInt(seat[0]) * 4 - 1;
		for (int i = stop - 3; i < stop; i++) {
			if(seats[i][1].equals(seat[1]) && isEmpty(seats[i])) {
				return true;
			}
		}
		
		return false;
	}

	private static boolean swapSeat(String[] seat, String[] foundPassenger) {
		if(convertToInt(foundPassenger[4]) < 16 && (convertToInt(seat[0]) >= 10 && convertToInt(seat[0]) <= 13)) {
			return false;
		}
		if(seatReallyEmpty(seat)) {
			if(reserveSeat(seat, foundPassenger[2], foundPassenger[3], convertToInt(foundPassenger[4]))) {
				return reserveSeat(foundPassenger, "empty", "empty", 0);
			}
		}
		
		return false;
	}

	private static int convertToInt(String string) {
		return Integer.valueOf(string);
	}

	private static String[] seatLabelParts(String seatLabel) {
		int length = seatLabel.length()-1;
		return new String[] { seatLabel.substring(0, length), seatLabel.substring(length) };
	}

	private static String[] getClassEmptySeats(String seatClass) {
		StringBuilder emptySeats = new StringBuilder();
		int index = seatClass.equalsIgnoreCase("first") ? 0 : 20;
		int stop  = seatClass.equalsIgnoreCase("first") ? 20 : 70;
		for (int i = index; i < stop; i++) {
			if(isEmpty(seats[i])) {
				emptySeats.append(seats[i][0]+seats[i][1].toUpperCase()+",");
			}
		}
		
		return emptySeats.length() > 0 ? emptySeats.toString().split(",") : null;
	}

	/**
	 * 
	 * @param String[][]
	 * @throws IOException
	 * 
	 * This method reads a CSV extension file from the file system, splits the elements on
	 * the commas and put each line into different arrays of size 4.
	 * 
	 * @return void
	 */
	private static void populateFlightDatabase(String destination, String[][] seats) throws IOException {
		openReadFile(String.format("%s%sList.csv", parent, destination), seats);
	}

	private static String customerMenu() {
		System.out.print(
				"\n1 - Check seat availability\n" +
				"2 - Make a reservation\n" +
				"3 - Print a boarding pass\n" +
				"4 - Print a receipt\n" +
				"5 - Change seat assignment\n\n" +
				"Please enter your choice: "
		);
		
		return sc.next();
	}
	
	private static String agentMenu() {
		System.out.println("\nWelcome, agent! What would you like to do today?\n");
		System.out.printf(
				"1 - Check \"no fly\" list\n" +
				"2 - Perform upgrade\n" +
				"3 - Print passenger roster\n" +
				"4 - Print sales report\n\n" +
				"Please enter your choice: "
		);
		
		return sc.next();
	}
	
	private static void printAvailableSeats(String[][] seats) {
		StringBuilder emptySeats = new StringBuilder();
		
		for (int i = 0; i < seats.length; i++) {
			try {
				if(isEmpty(seats[i])) {
					emptySeats.append(String.format("%s - %s - %s%n", 
							getSeatLabel(seats[i]), getTicketClass(seats[i]), getSeatPosition(seats[i])
						));
				}
			} catch (NullPointerException e) {
				continue;
			}
		}
		
		System.out.println(emptySeats);
	}
	
	private static void makeReservation(String[][] seats) {
		Scanner input = new Scanner(System.in);
		try {
			String emptySeats = emptySeatsAvailable(seats);
			String[] empty = emptySeats.split(",");
			
			int firstClassAisleSeats = 0;
			int firstClassWindowSeats = 0;
			
			int economyClassAisleSeats = 0;
			int economyClassWindowSeats = 0;
			
			//emergency seats
			int emergencyAisleSeats = 0;
			int emergencyWindowSeats = 0;
			int economyClassEmergencySeats = 0;
			
			for (String seat : empty) {
				int seatClass = convertToInt(seat.substring(0, seat.length()-1));
				String seatPosition = seat.substring(seat.length()-1);
				
				if(seatClass > 0 && seatClass <= 5) {
					if(seatPosition.equalsIgnoreCase("a") || seatPosition.equalsIgnoreCase("d")) {
						firstClassWindowSeats++;
						continue;
					}
					firstClassAisleSeats++;
					
				} else if(seatClass > 5 && seatClass <= 18) {
					if(seatClass >= 10 && seatClass <= 13) { 
						if(seatPosition.equalsIgnoreCase("a") || seatPosition.equalsIgnoreCase("d")) {
							emergencyWindowSeats++;
						} else if(seatPosition.equalsIgnoreCase("b") || seatPosition.equalsIgnoreCase("c")) {
							emergencyAisleSeats++;
						}
						economyClassEmergencySeats++; 
					}
					
					if(seatPosition.equalsIgnoreCase("a") || seatPosition.equalsIgnoreCase("d")) {
						economyClassWindowSeats++;
						continue;
					}
					economyClassAisleSeats++;
					
				} else {
					
				}
			}
			
			//get the total of first class seats available as well as economy seats
			int firstClassSeats = firstClassAisleSeats + firstClassWindowSeats;
			int economyClassSeats = economyClassAisleSeats + economyClassWindowSeats;
			
			boolean exitFlag = false;
			
			System.out.print("What is your first name? ");
			firstname = input.nextLine();
			
			System.out.print("What is your last name? ");
			lastname = input.nextLine();
			
			//if there's already a reserved seat with these first and last names, inform and exit
			if(nameAlreadyExists()) {
				System.out.println("\nPassengers with the same first and last names cannot join the same flight.\n" +
						"A passenger has already booked with the same name as yours.\n");
//				if(changesMadeToFile) { saveToFile(destination); }
//				System.exit(0);
				return;
			}
			
			System.out.print("What is your age? ");
			age = sc.nextInt();
			sc.nextLine(); //clear input from the Scanner object
			
			String ticketClass = getTicketClass(economyClassSeats, firstClassSeats);
			String seatPosition = null;
			//String[] seat = null;
			
			//boolean emergencyExit = emergencyExitSeatReserved();
			
			if(isAnswer("economy", ticketClass)) {
				exitFlag = getEmergencyExitFlag(economyClassEmergencySeats, age);
				seatPosition = exitFlag ? getSeatPosition(emergencyAisleSeats, emergencyWindowSeats) :
					 getSeatPosition(economyClassAisleSeats, economyClassWindowSeats);
				
				if(seatPosition == null) { return; }
				seat = getEconomyClassSeat(seats, exitFlag, seatPosition);
				
			} else if(isAnswer("first class", ticketClass)) {
				seatPosition = getSeatPosition(firstClassAisleSeats, firstClassWindowSeats);
				
				if(seatPosition == null) { return; }
				seat = getFirstClassSeat(seats, seatPosition);
				
			} else {
				//when customer's choice is neither economy or first class, throw an InputMismatchException
				//and exit, without error message.
				throw new InputMismatchException();
			}
			
			//reserve a seat for this customer
			if(reserveSeat(seat, firstname, lastname, age)) {
				System.out.printf("Thank you %s %s! You are now booked in %s seat %s.\n",
						capitalize(firstname), capitalize(lastname), seat[6], seat[0]+seat[1].toUpperCase());
				changesMadeToFile = true;
			}
			
		} catch (InputMismatchException e) {
			//wrong input type submitted by user. for e.g. anything apart from an integer as age
			System.out.println("\nYou have supplied wrong information. You may restart the process of reserving\n" +
					"a seat on this flight or you may come back later. Thank you\n");
			sc.nextLine();
		}
		
		
	}
	
	private static boolean nameAlreadyExists() {
		if(nameExists(lastname)) {
			return true;
		}
		return false;
	}

	private static boolean nameExists(String name) {
		for (int i = 0; i < seats.length; i++) {
			if(seats[i][3].equalsIgnoreCase(name)) {
				return true;
			}
		}
		return false;
	}

	private static boolean reserveSeat(String[] s, String fN, String lN, int a) {
		String age = Integer.toString(a);
		int stop = (convertToInt(s[0]) * 4) - 1;
		
		for (int i = stop-3; i < seats.length; i++) {
			if(seats[i][1].equals(s[1])) {
				seats[i][2] = fN.equalsIgnoreCase("empty") ? "empty" : capitalize(fN);
				seats[i][3] = lN.equalsIgnoreCase("empty") ? "empty" : capitalize(lN);
				seats[i][4] = age;
				
				return true;
			}
		}
		
		return false;
	}

	private static boolean getEmergencyExitFlag(int economyClassEmergencySeats, int age) {
		
		String exit = null;
		if(economyClassEmergencySeats > 0 && age >= 16) {
			//there are seats in the economy class and in the emergency exit row too.
			//btw, the emergency exit row seats are in the economy class. the customer is 16 or above
			System.out.print("Would you like an emergency exit row seat? ");
			exit = sc.next();
			
		} else if(age >= 16) {
			//there are seats available in the economy class. but all seats in emergency
			//exit rows have been reserved.
			System.out.println("\nAll seats in the emergency exit rows have been reserved.\n");
		} else {
			//even if there are seats in the emergency exit row, the customer is too young (less than 16)
			//to sit in an emergency exit seat
			System.out.println("\nPerson below age 16 are not allowed to sit in emergency seat.\n");
		}
		
		return isAnswer("yes", exit);
	}

	private static String getSeatPosition(int aisle, int window) {
		if(aisle > 0 && window > 0) {
			System.out.print("What is your seat type preference (aisle or window)? ");
			String response = sc.next();
			if(isAnswer("window", response)) {
				return "window";
				
			} else if(isAnswer("aisle", response)) {
				return "aisle";
			} else {
				System.out.println("\nNo such seat.\n");
				return null;
			}
			
		} else if(aisle > 0) {
			System.out.print("\nAll window seats have been reserved.\nWould you like a seat by the aisle? ");
			if(isAnswer("yes", sc.next())) { return "aisle"; }
			else {
				System.out.print("\nWould you like any other seat in the non-emergency rows of the economy class? ");
				if(isAnswer("yes", sc.next())) { 
					//offer other seats in the economy class
					
				}
				else {
					System.out.println("\nThank you for using Airline Reservation System! Good bye!");
					System.exit(0);
				}
			}
		} else if(window > 0) {
			System.out.print("\nAll aisle seats have been reserved.\nwould you like a seat by the window? ");
			if(isAnswer("yes", sc.next())) { return "window"; }
			else {
				if(!tryAgain()) {
					System.exit(0);
				}
			}
		}
		
		return null;
	}

	private static String getTicketClass(int economyClassSeats, int firstClassSeats) {
		
		String ticketClass = null;
		
		if(economyClassSeats > 0 && firstClassSeats > 0) {
			System.out.print("Would you like a first class or economy class seat? ");
			ticketClass = sc.nextLine();
			
		} else if(economyClassSeats > 0) {
			System.out.print("All seats in the first class have been reserved." +
					"\nWould you like an economy class seat? ");
			if(isAnswer("yes", sc.next())) {
				ticketClass = "economy";
			}
			
		} else if(firstClassSeats > 0) {
			System.out.print("All seats in the economy class class have been reserved." +
					"\nWould you like a first class seat? ");
			if(isAnswer("yes", sc.next())) {
				ticketClass = "first class";
			}
		}
		
		return ticketClass;
	}

	private static void printReceipt() {
		try {
			System.out.print("Please enter the number of passengers on the receipt: ");
			int numberOfPassengers = sc.nextInt();
			sc.nextLine();
			
			StringBuilder receipt = new StringBuilder();
			
			if(numberOfPassengers > 0) {
				for (int i = 0; i < numberOfPassengers; i++) {
					System.out.print("Please enter the last name of a passenger: ");
					String lastname = sc.nextLine();
					
					String passengerReceipt = receiptOf(lastname);
					if(passengerReceipt == null) {
						throw new Exception();
					}
					
					receipt.append(passengerReceipt);
				}
			} else {
				System.out.printf("\nInvalid number of passengers specified [%s].\n" +
						"Receipts cannot be printed. Thank you\n", String.valueOf(numberOfPassengers));
				return;
			}
			
			System.out.println("-------------------------------------");
			System.out.println(receipt);
			System.out.printf("Total: %.0f GHc\n", total);
			System.out.println("-------------------------------------\n");
			
			total = 0.0; //reset total to 0
			
		} catch(InputMismatchException e) {
			System.out.println("\nAn integer was expected.\n\n");
			sc.nextLine();
			
		} catch(Exception ex) {  }
	}
	
	private static String receiptOf(String lastname) {
		String[] passenger = findPassengerByLastName(lastname);
		if(passenger == null) {
			System.out.println("\nNo such passenger(s) on this flight.\n");
			return null;
		}
		
		double ticketPrice = passenger[7].equalsIgnoreCase("economy") ? ticketPrices[0] : ticketPrices[1];
		total += ticketPrice;
		
		return String.format(
					"Name: %s %s\n" +
					"Departure Date: XX/XX/XXXX\n" +
					"Destination: ACC to %s\n" +
					"Class: %s\n" +
					"Ticket Price: %.1f GHc\n\n",
					capitalize(passenger[2]), capitalize(passenger[3]), getRouteName(), capitalize(passenger[7]),
					ticketPrice
				);
	}

	private static void printBoardingPass() {
		System.out.print("Please enter your last name: ");
		String lastName = sc.next();
		
		String[] passenger = findPassengerByLastName(lastName);
		if(passenger != null) {
			System.out.println();
			System.out.printf(
					"Here is your boarding pass:\n\n" +
					"----------------------------------\n" +
					"Name: %s %s\n" +
					"Depature Date: XX/XX/XXXX\n" +
					"Destination: ACC to %s\n" +
					"Class: %s\n" +
					"Seat: %s\n" +
					"----------------------------------\n\n",
					capitalize(passenger[2]), capitalize(passenger[3]), getRouteName(), capitalize(passenger[7]),
					  passenger[0]+passenger[1].toUpperCase()  
				);
		} else {
			System.out.println("Sorry, there is not such passenger booked for this flight.\n");
		}
	}
	
	private static String[] findPassengerByLastName(String lastname) {
		for(String[] passenger : seats) {
			if(passenger[3].equalsIgnoreCase(lastname)) {
				return passenger;
			}
		}
		
		return null;
	}
	
	private static String getRoute(String clientType) throws Exception {
		String client = null;
		
		if(isAnswer("customer", clientType)) { client = "customer"; }
		else if(isAnswer("gate agent", clientType) || isAnswer("agent", clientType)) { 
			client = "agent"; 
		}
		
		else { 
			System.out.println("\nYou should be either a customer or a gate agent to use this system.\n");
			throw new Exception();
		}
		
		System.out.printf("\nWelcome, %s! which flight would you like to use?\n\n" +
				"1 - ACC to TAK\n" +
				"2 - ACC to TAM\n" +
				"3 - ACC to KUM\n\n" +
				"Please enter your choice: ", client);
		
		String destination = null;
		
		switch(sc.nextInt()) {
			case 1:
				destination = "takoradi";
				break;
			case 2:
				destination = "tamale";
				break;
			case 3:
				destination = "kumasi";
				break;
		}
		
		if(destination == null) {
			throw new InputMismatchException();
		}
		
		return destination;
	}
	
	private static void openReadFile(String path, String[][] seats) throws IOException {
		try {
			//set to read from the file...
			Scanner reservationsFileReader = new Scanner(new File(path));
			
			int index = 0; //indexer for first class section
			
			//read away the headers for the csv document
			reservationsFileReader.nextLine();
			
			//fill the seats with reservation information in the file
			while(reservationsFileReader.hasNextLine()) {
				String[] passenger = reservationsFileReader.nextLine().split(",");
				int compartmentNumber = convertToInt(passenger[0]);
				
				if(compartmentNumber > 0 && compartmentNumber <= 18) {
					//shovel them into the first class section
					seats[index] = passenger;
					index++;
					
				} else {
					continue; //ignore passengers for sections that are not available on this flight
				}
			}
			
			reservationsFileReader.close();
			
		} catch (FileNotFoundException e) {
			//in case records cannot be read from a file, exit
			System.out.println("\nSorry but this flight is not ready yet for booking. Thank you.");
			System.err.println("error reading database of reservations already made. check /path/to/file.csv");
			System.exit(1);
		}
	}
	
	private static String getSeatLabel(String[] seat) {
		return seat[0] + seat[1];
	}
	
	private static String getTicketClass(String[] seat) {
		return seat[7];
	}
	
	private static String getSeatPosition(String[] seat) {
		return seat[6];
	}

	private static String emptySeatsAvailable(String[][] seats) {
		
		StringBuilder emptySeats = new StringBuilder();
		
		for (int i = 0; i < seats.length; i++) {
			try {
				if(isEmpty(seats[i])) {
					emptySeats.append(String.format("%s,", seats[i][0]+seats[i][1]));
				}
			} catch (NullPointerException e) {
				continue;
			}
		}
		
		return emptySeats.toString();
	}
	
	private static boolean isAnswer(String requiredAnswer, String suppliedAnswer) {
		try {
			return requiredAnswer.substring(0, suppliedAnswer.length()).equalsIgnoreCase(suppliedAnswer);
			
		} catch(Exception e) { return false; }
	}
	
	private static String[] getFirstClassSeat(String[][] seats, String position) {
		String[] foundSeat = null;
		for (int i = 0; i < 20; i++) {
			if(isEmpty(seats[i])) {
				foundSeat = getSeat(seats, position, "window", "aisle", i);
				if(foundSeat != null) { break; }
			}
		}
		
		return foundSeat;
	}
	
	private static String[] getEconomyClassSeat(String[][] seats, boolean emergency, String position) {
		return getClassSeat(20, seats.length, seats, emergency, position);
	}

	private static String[] getClassSeat(int start, int stop, String[][] seats, boolean emergency, String position) {
		String[] foundSeat = null;
		for (int i = start; i < stop; i++) {
			if(isEmpty(seats[i])) {
				if(emergency) {
					if(Boolean.valueOf(seats[i][5])) {
						foundSeat = getSeat(seats, position, "window", "aisle", i);
						if(foundSeat != null) { break; }
					}
				} else {
					if(!Boolean.valueOf(seats[i][5])) {
						foundSeat = getSeat(seats, position, "window", "aisle", i);
						if(foundSeat != null) { break; }
					}
				}
			}
		}
		
		return foundSeat;
	}
	
	private static String[] getSeat(String[][] seats, String position, String window, String aisle, int i) {
		if(position.equals(window) && (seats[i][1].equals("a") || seats[i][1].equals("d"))) {
			return new String[] { seats[i][0], seats[i][1] };
		} else if(position.equals(aisle) && (seats[i][1].equals("b") || seats[i][1].equals("c"))) {
			return new String[] { seats[i][0], seats[i][1] };
		}
		
		return null;
	}

	private static boolean isEmpty(String[] seat) {
		//returns true if the given row in the 2-dimensional array has "empty" in both columns 3 and 4
		return seat[2].equalsIgnoreCase("empty") && seat[3].equalsIgnoreCase("empty");
		
	}

	private static void saveToFile(String path) {
		try {
			FileWriter destinationFile = new FileWriter(
					String.format("src/airlinereservationsystem_yawboakyeyiadom/files/%sList.csv", path)
				);
			destinationFile.write("row,seat,first,last,age,exit row flag,seat position,ticket class\r\n");
			for(String[] passenger : seats) {
				for (int i = 0; i < 8; i++) {
					if (i == 7) { destinationFile.write(String.format("%s", passenger[i])); continue; }
					destinationFile.write(String.format("%s,", passenger[i]));
				}
				
				destinationFile.write("\r\n");
			}
			
			destinationFile.flush();
			destinationFile.close();
			
		} catch(IOException e) {
			
		}
	}

	private static String capitalize(String string) {
		//capitalize only the first letter of the string
		return Character.toUpperCase(string.charAt(0)) + string.substring(1);
	}
}