Lines won't print inside while loop

Question

I don't know why the lines won't print in the while loop. I can't exit either. Please help. The program runs but nothing inside the while loop will print.

public class RomanNumeralHelper {

    /**
     * (Insert a brief description that describes the purpose of this method)
     *
     * @param args
     */
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String myRoman;
        String upperRoman;

        System.out.print("Enter a roman numeral [Q | q to quit]: ");
        myRoman = in.next();
        upperRoman = myRoman.toUpperCase();

        while (upperRoman != "Q") {
            if (upperRoman == "I") {
                System.out.println(">> 1");
            } else if (upperRoman == "II") {
                System.out.println(">> 2");
            } else if (upperRoman == "III") {
                System.out.println(">> 3");
            } else if (upperRoman == "IV") {
                System.out.println(">> 4");
            } else if (upperRoman == "V") {
                System.out.println(">> 5");
            }

            System.out.print("Enter a roman numeral [Q | q to quit]: ");
            myRoman = in.next();
            upperRoman = myRoman.toUpperCase();
        }

        System.out.println("Good Bye!");

        // (5) Closes the in object to avoid a resource leak.
        in.close();
    }
}

Use `String`'s `equals` method to compare string values, not the `==` operator. — rgettman, Feb 04 '14 at 01:17

score 3 · Accepted Answer · answered Feb 04 '14 at 01:17

3

Compare strings with equals() not with ==

answered Feb 04 '14 at 01:17

Martin Dinov

8,757
3
29
41

1

I should have known; I saw that in my textbook. Thanks for your help! – user3263352 Feb 04 '14 at 01:21

score 0 · Answer 2 · answered Feb 04 '14 at 01:23

You could also clean it up by not changing it to uppercase and using .equalsIgnoreCase() to compare strings.

Also, you could include the first print inside the while loop rather than repeating at the end of the loop. These are just little tips to clean up your code a little bit.

Lines won't print inside while loop

2 Answers2