Altering Multiple Values of Arrays

Question

I'm building a booking system where I ask the user for a boarding and destination point. There are six stations, and I want to subtract the number of passengers from the boarding and destination point and all of the in-between stations.

TrainService.java class:

// Prompt user for the boarding point.
System.out.println("\n0. Lorem");
System.out.println("1. Ipsum");
System.out.println("2. Dolor");
System.out.println("3. Sit");
System.out.println("4. Amet\n");

System.out.print("Select a boarding point: ");
String boardingPoint = sc.nextLine();
int boardingPointNum = Integer.parseInt(boardingPoint);

// Prompt user for the destination point.
System.out.println("\n1. Ipsum");
System.out.println("2. Dolor");
System.out.println("3. Sit");
System.out.println("4. Amet");
System.out.println("5. Consectetur\n");

System.out.print("Select a destination point: ");
String destinationPoint = sc.nextLine();
int destinationPointNum = Integer.parseInt(destinationPoint);

// Reduce the number of available seats to the respective stations.
for (int i = 0; i < 5; i++) {
    if (boardingPoint.equals("0") && destinationPoint.equals(Integer.toString(i + 1))) {
        numOfFirstClassSeats[0 - i] -= numOfFirstClassAdults;
        stationList.setNumOfFirstClassSeats(numOfFirstClassSeats);
        break;
    }
}
...

BookingSystem.java class:

// Instance variables.
private String[] stations = {"Lorem", "Ipsum", "Dolor", "Sit", "Amet", "Consectetur"};
private int[] numOfFirstClassSeats = {48, 48, 48, 48, 48};

public int[] getNumOfFirstClassSeats() {
    return this.numOfFirstClassSeats;
}

public void setNumOfFirstClassSeats(int[] numOfFirstClassSeats) {
    this.numOfFirstClassSeats = numOfFirstClassSeats;
}

public void printStations() {
    System.out.println("\n~ AVAILABLE SEATS ~");
    System.out.println("-------------------\n");

    String pattern = "%-20s %-20s %-21s %-23s %-20s\n";

    System.out.printf(pattern, "DEPARTING", "ARRIVING", "FIRST CLASS", "STANDARD CLASS", "EXCURSION CLASS");
    System.out.println("-------------------------------------------------------------------------------------------------------");
    for (int i = 0; i < 5; i++) {
        System.out.format(pattern, stations[i], stations[i + 1], getNumOfFirstClassSeats()[i], getNumOfStandardSeats()[i], getNumOfExcursionSeats()[i]);
    }
}

Problem 1: When I run the code to book a First Class seat, the code only alters the available seats for "Lorem" and "Ipsum" if the boarding point is "Lorem" and the destination point is "Ipsum".

If I choose the boarding point as "Lorem" and the destination point is "Sit", the output is: Index -2 out of bounds for length 5.

Problem 2: If I have 5 passengers and "Lorem" is the boarding point and "Amet" is the destination point, I want the available seats to be reduced to 43 passengers from "Lorem" to "Amet".

How do I accomplish this? Thank you for your help!

Nicholas · Accepted Answer · 2020-03-21 14:24:05Z

2

An alternative way of doing this may be to consider using Maps to map different boarding points and destinations. I wouldn't say it would be too verbose because there are a limited number of combinations, but it could solve Problem 2.

If a passenger selects a boarding point and destination point, you can compare the values they entered to a Map, then reduce the passengers for that certain combination.

Could you also display the error log for Problem 1? That would give me a better idea of what the issue is.

answered Mar 21, 2020 at 14:24

Nicholas

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Comments

Steffi · Accepted Answer · 2020-03-21 15:04:34Z

1

For problem 1 please post the whole code.

Problem 2:

It's only a thought-provoking impulse.

I would make it like this:

        System.out.println(Arrays.toString(numOfFirstClassSeats));        
        for(int i=0; i<numOfFirstClassSeats.length; i++){
            if((destinationPoint >= i)&(boardingPointNum <= i)){
                numOfFirstClassSeats[i] = numOfFirstClassSeats[i]-1;
            }
        }        
        System.out.println(Arrays.toString(numOfFirstClassSeats));

But you have to add some security if's. If you only go one station boardingPointNum = destinationPoint

edited Mar 21, 2020 at 15:04

answered Mar 21, 2020 at 14:56

Steffi

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Comments

Wolfizzy · Accepted Answer · 2020-03-22 05:42:37Z

1

Check this line in TrainService.java:

numOfFirstClassSeats[0 - i]

As i increments, the value goes to negative, so it should be:

numOfFirstClassSeats[i - 0]

edited Mar 22, 2020 at 5:42

Wolfizzy

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answered Mar 21, 2020 at 14:22

Amit Kumar Lal

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2 Comments

Amit Kumar Lal Over a year ago

If the answer helped u do u mind up voting and accepting the answer.. Thanks in advance

WJS Over a year ago

How about just numOfFirstClassSeats[i]?

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