NumberInText.java

import javax.swing.*;

public class NumberInText {

    /**
    *   Program:    NumberInText.java
    *   Purpose:    Display a number between 1 and 900 (inclusive) in English words
    *   Creator:    Chris Clarke
    *   Modified:   19.05.2015
    */

    public static void main(String[] args) {
        final int MIN = 1;
        final int MAX = 900;
        int number=0;
        String num1;

        do {
            num1 = JOptionPane.showInputDialog ("Enter number between "+MIN+" and "+MAX);
            number = Integer.parseInt(num1);
        } while (number<MIN || number>MAX);

        System.out.println (getNumberWord (number));
    } // end main()

    public static String getNumberWord(int num) {

        switch (num) {
            case 0: return "Zero";
            case 1: return "One";
            case 2: return "Two";
            case 3: return "Three";
            case 4: return "Four";
            case 5: return "Five";
            case 6: return "Six";
            case 7: return "Seven";
            case 8: return "Eight";
            case 9: return "Nine";
            case 10: return "Ten";
            case 11: return "Eleven";
            case 12: return "Twelve";
            case 13: return "Thirteen";
            case 14: return "Fourteen";
            case 15: return "Fifteen";
            case 16: return "Sixteen";
            case 17: return "Seventeen";
            case 18: return "Eighteen";
            case 19: return "Nineteen";
            default: return twentyPlus(num);
        } // end switch

    } // end getNumberWord()

    public static String twentyPlus(int num) {

        String word = "";
        int hundreds, tens, units=0;

        hundreds = num / 100;

        switch (hundreds) {
            case 0: break;
            case 1: word="One Hundred "; break;
            case 2: word="Two Hundred "; break;
            case 3: word="Three Hundred "; break;
            case 4: word="Four Hundred "; break;
            case 5: word="Five Hundred "; break;
            case 6: word="Six Hundred "; break;
            case 7: word="Seven Hundred "; break;
            case 8: word="Eight Hundred "; break;
            case 9: word="Nine Hundred "; break;
        } // switch

        num -= (hundreds*100);
        tens = num / 10;

        switch (tens) {
            case 2: word+="Twenty "; break;
            case 3: word+="Thirty "; break;
            case 4: word+="Forty "; break;
            case 5: word+="Fifty "; break;
            case 6: word+="Sixty "; break;
            case 7: word+="Seventy "; break;
            case 8: word+="Eighty "; break;
            case 9: word+="Ninety "; break;
            default: break;
        } // end switch

        if (tens>=2) num -= (tens*10);
        units = num;

        if (units>0) {
            word+=getNumberWord (units);
        } // end if

        return word;
    } // end twentyPlus()

} // end class NumberInText