How can I fix this java?

Question

I am working on this program with these instructions:

Bus Passengers: Write a program that is to be used to count how many passengers are travelling on buses that pass a particular bus stop in a given hour. It should use a while loop to repeatedly ask the user to give the number of passengers on the bus that just passed. It should stop when the special code X is entered as the number of passengers. It should then give the number of buses and the total number of passengers counted in that hour. For example, one run might be as follows.

How many passengers were on the bus? 2
How many passengers were on the bus? 5
How many passengers were on the bus? 10
How many passengers were on the bus? 3
How many passengers were on the bus? 12
How many passengers were on the bus? 1
How many passengers were on the bus? 0
How many passengers were on the bus? X

There were a total of 33 passengers on 7 buses.

I am trying to fix an error:

Answer 1

Few points to note:-

1. You don't need System.exit()
2. In java variables are only accessible inside their scope ie the region they are created in.

I tried to rewrite code as following:-

import java.util.Scanner;

public class Bus {
    int busCount =0;
    int passengerCount =0;
    Scanner scanner= new Scanner(System.in);

    public static void main(String args[]){
        Bus bus = new Bus();
        bus.getResults();
    }

    private void addBusAndPassenger(String input){
        try{
            int a = Integer.parseInt(input);
            busCount = busCount + 1;
            passengerCount = passengerCount + a;
        }catch(NumberFormatException e){
            System.out.println("Please provide integer or X as input");
        }
    }

    private void getResults(){
        String a =null;
        while (!("X".equals(a))){
            System.out.print("How many passengers were on the bus? ");
            a = scanner.nextLine();
            if("X".equals(a))
                break;

            addBusAndPassenger(a);
        }
        System.out.println("There were a total of " + passengerCount + " passengers on " + busCount + " buses.");
    }
}

Answer 2

A few things here. Other people pointed this out, but you need to pass parameters to your method. The method signature is there for a reason - your method calls must match the method signature you define.

Also, busInformation is supposed to return an int , but it returns nothing.

Also, this line:

Integer.parseInt(a);

does nothing - you throw away the result immediately. It won't modify the string in place or anything like that. (Well, I suppose that it'll throw an exception if they enter something other than an integer, but that doesn't seem to be what you're trying to do with this line).

At an absolute minimum, you should change the return type of your method to int and the change this line to return Integer.parseInt(a); .

(You also shouldn't be creating a new scanner every time like this - you should just re-use the same one).