//RecursionDemo.java

import java.util.*;

public class RecursionDemo
{
    public static void main(String[] args)
    {
         System.out.println("Enter an integer:");
         Scanner keyboard = new Scanner(System.in);;
         int number = keyboard.nextInt( );
         System.out.println("The digits in that number are:");
         inWords(number);
         System.out.println( );
         System.out.println("If you add ten to that number, ");
         System.out.println("the digits in the new number are:");
         number = number + 10;
         inWords(number);
         System.out.println( );
    }


    /**
     Precondition: number >= 0
     Action: The digits in number are written out in words.
    */
    public static void inWords(int number)
    {
        if (number < 10)
            System.out.print(digitWord(number) + " ");
        else //number has two or more digits
        {
            inWords(number/10);
            System.out.print(digitWord(number%10) + " ");
        }
    }

    /**
     Precondition: 0 <= digit <= 9
     Returns the word for the argument digit.
    */
    private static String digitWord(int digit)
    {
        String result = null;
        switch (digit)
        {
            case 0:
                result = "zero";
                break;
            case 1:
                result = "one";
                break;
            case 2:
                result = "two";
                break;
            case 3:
                result = "three";
                break;
            case 4:
                result = "four";
                break;
            case 5:
                result = "five";
                break;
            case 6:
                result = "six";
                break;
            case 7:
                result = "seven";
                break;
            case 8:
                result = "eight";
                break;
            case 9:
                result = "nine";
                break;
            default:
                System.out.println("Fatal Error.");
                System.exit(0);
                break;
        }
        return result;
    }
}