Using a while loop in an ArrayList

Question

I'm new to programming and to this website, so here goes. I wanted to write a program that would allow as many input strings as possible to be added to an ArrayList . So I used a while loop in the following code. What I intended was for the loop to break if the input was 0 .

import java.util.*;

public class AddToList2
{
static Scanner q = new Scanner(System.in);

public static void main(String[] args)
{
    ArrayList<String> inputlist = new ArrayList<String>();
    while (true)
    {
        System.out.print("Enter something here: ");
        String x = q.nextLine();
        inputlist.add(x);
        if (x.equals("0"));
            break;
    }
}

The program was compiled without error, but sadly, when I ran the program many times, the loop broke no matter what the input was. Any way to solve this?

Well, that was careless of me! Anyway, I had created that program in order to find out what was wrong with this :

ArrayList<String> endangeredlist = new ArrayList<String>();
    ArrayList<Integer> popn = new ArrayList<Integer>();
    while (true)
    {
        System.out.print("Name an animal: ");
        String animal = q.nextLine();
        endangeredlist.add(animal);
        if (animal.equals("EXTERMINATE"))
            break;          
        q.next();
        System.out.print("How many are left in the wild? ");
        int numberleft = q.nextInt();
        popn.add(new Integer(numberleft));
    }

(This is part of a much larger program.) My intention was for the loop to break when the animal name input was EXTERMINATE . Sadly the program throws a NoSuchElement exception if the input first time round was EXTERMINATE , and if I had inputted something else first the loop would start, but then inputting EXTERMINATE second time round does not break the loop. Why is that?

Answer 1

You have an extraneous semicolon after your if , which effectively makes it

if (x.equals("0")) { }
break;

Answer 2

Your if statement is broken

if (x.equals("0"));

This is basically saying if (x.equals("0")) do nothing...

This is one of the reasons why you should use parenthesis around your if statements

if (x.equals("0")) {
    break;
}

Answer 3

You have a semi-colon at the end of your condition.

This turns the break into a statement of its own, without the condition.