Fraction Calculator

/**
 * Jessica Wong
 *
 */

import java.util.*;
public class Main
{
    public static void main(String[] args)
    {

        Scanner scan = new Scanner(System.in);
        String input = "";
        System.out.println("Enter a string to be converted into a fraction. Ex. 2_3/5 is the same as saying 2 3/5 | Type 'quit' in order to stop the program.");
        while (!input.equalsIgnoreCase("quit"))
        {
            input = scan.next();
            if (!input.equalsIgnoreCase("quit"))
            {
                System.out.println(input + " as a fraction is: " + convertToFraction(input));
            }
        }
    }
    public static int getNumerator(String fraction)
    {
        String numerator;
        if (fraction.indexOf('_') != -1)
        {
            numerator = fraction.substring(fraction.indexOf('_') + 1,fraction.indexOf('/'));
            String wholenum = fraction.substring(0,fraction.indexOf('_'));
            return Integer.parseInt(numerator,10)+Integer.parseInt(wholenum,10)*getDenominator(fraction);
        }
        else if (fraction.indexOf('/') != -1)
        {
            numerator = fraction.substring(0,fraction.indexOf('/'));
            return Integer.parseInt(numerator,10);
        }
        else
        {
            return Integer.parseInt(fraction,10);
        }
    }
    public static int getDenominator(String fraction)
    {
        if (fraction.indexOf('/') != -1)
        {
            String denominator = fraction.substring(fraction.indexOf('/') + 1, fraction.length());
            return Integer.parseInt(denominator,10);
        }
        else
        {
            return 1;
        }
    }
    public static String convertToFraction(String input)
    {
        if (input.indexOf('/') != -1)
        {
            return (getNumerator(input) + "/" + getDenominator(input));
        }
        else
        {
            return input;
        }
    }
}