How to convert number to words in java

Question

We currently have a crude mechanism to convert numbers to words (e.g. using a few static arrays) and based on the size of the number translating that into an english text. B

Answer 1

The same accepted answer (Jigar Joshi), but now in Spanish. Feel free to change this if you find a mistake. Easier than french, but based on that though....

Spanish:

import java.text.*;

class SpanishNumberToWords {
  private static final String[] tensNames = {
    "",
    "",
    "veinte",
    "treinta",
    "cuarenta",
    "cincuenta",
    "sesenta",
    "setenta",
    "ochenta",
    "noventa"
  };

  private static final String[] unitNames1 = {
    "",
    "un",
    "dos",
    "tres",
    "cuatro",
    "cinco",
    "seis",
    "siete",
    "ocho",
    "nueve",
    "diez",
    "once",
    "doce",
    "trece",
    "catorce",
    "quince",
    "dieciseis",
    "diecisiete",
    "dieciocho",
    "diecinueve",
    "veinte",
    "veintiun",
    "veintidos",
    "veintitres",
    "veinticuatro",
    "veinticinco",
    "veintiseis",
    "veintisiete",
    "veintiocho",
    "veintinueve",
  };

  private static final String[] unitNames2 = {
    "",
    "",
    "dosc",
    "tresc",
    "cuatroc",
    "quin",
    "seisc",
    "setec",
    "ochoc",
    "novec",
    "diez"
  };

  private SpanishNumberToWords() {}

  private static String convertZeroToHundred(int number) {

    int theTens = number / 10;
    int theUnit = number % 10;
    String result = "";

    // separator
    String theSeparator = "";
    if (theTens > 1) {
        theSeparator = " y ";
    }
    // particular cases
    switch (theUnit) {
    case 0:
        theSeparator = "";
      break;
    default:
    }

    // tens in letters
    switch (theTens) {
    case 0:
        result = unitNames1[theUnit];
      break;
    case 1: case 2:
        result =  unitNames1[theTens*10+theUnit];
        break;
    default :
        result = tensNames[theTens]
                              + theSeparator + unitNames1[theUnit];
    }
    return result;
  }

  private static String convertLessThanOneThousand(int number) {

    int theHundreds = number / 100;
    int leReste = number % 100;
    String sReste = convertZeroToHundred(leReste);

    String result;
    switch (theHundreds) {
    case 0:
        result = sReste;
      break;
    case 1 :
      if (leReste > 0) {
          result = "ciento " + sReste;
      }
      else {
          result = "cien";
      }
      break;
    default :
      if (leReste > 0) {
          result = unitNames2[theHundreds] + "ientos " + sReste;
      }
      else {
          result = unitNames2[theHundreds] + "ientos";
      }
    }
    return result;
  }

  public static String convert(long number) {
    // 0 à 999 999 999 999
    if (number == 0) { return "cero"; }

    String snumber = Long.toString(number);

    // pad des "0"
    String mask = "000000000000";
    DecimalFormat df = new DecimalFormat(mask);
    snumber = df.format(number);

    // XXXnnnnnnnnn
    int theMilliards = Integer.parseInt(snumber.substring(0,3));
    // nnnXXXnnnnnn
    int theMillions  = Integer.parseInt(snumber.substring(3,6));
    // nnnnnnXXXnnn
    int theCentMiles = Integer.parseInt(snumber.substring(6,9));
    // nnnnnnnnnXXX
    int lesMille = Integer.parseInt(snumber.substring(9,12));

    String tradMilliards;
    switch (theMilliards) {
    case 0:
      tradMilliards = "";
      break;
    case 1 :
      tradMilliards = convertLessThanOneThousand(theMilliards)
         + " mil millones ";
      break;
    default :
      tradMilliards = convertLessThanOneThousand(theMilliards)
         + " mil millones ";
    }
    String resultat =  tradMilliards;

    String tradMillions;
    switch (theMillions) {
    case 0:
      tradMillions = "";
      break;
    case 1 :
      tradMillions = convertLessThanOneThousand(theMillions)
         + " millon ";
      break;
    default :
      tradMillions = convertLessThanOneThousand(theMillions)
         + " millones ";
    }
    resultat =  resultat + tradMillions;

    String tradCentMille;
    switch (theCentMiles) {
    case 0:
      tradCentMille = "";
      break;
    case 1 :
      tradCentMille = "mil ";
      break;
    default :
      tradCentMille = convertLessThanOneThousand(theCentMiles)
         + " mil ";
    }
    resultat =  resultat + tradCentMille;

    String tradMille;
    tradMille = convertLessThanOneThousand(lesMille);
    resultat =  resultat + tradMille;

    return resultat;
  }

  public static void main(String[] args) {
    System.out.println("*** " + SpanishNumberToWords.convert(0));
    System.out.println("*** " + SpanishNumberToWords.convert(1));
    System.out.println("*** " + SpanishNumberToWords.convert(2));
    System.out.println("*** " + SpanishNumberToWords.convert(3));
    System.out.println("*** " + SpanishNumberToWords.convert(4));
    System.out.println("*** " + SpanishNumberToWords.convert(5));
    System.out.println("*** " + SpanishNumberToWords.convert(7));
    System.out.println("*** " + SpanishNumberToWords.convert(12));
    System.out.println("*** " + SpanishNumberToWords.convert(16));
    System.out.println("*** " + SpanishNumberToWords.convert(19));
    System.out.println("*** " + SpanishNumberToWords.convert(21));
    System.out.println("*** " + SpanishNumberToWords.convert(24));
    System.out.println("*** " + SpanishNumberToWords.convert(28));
    System.out.println("*** " + SpanishNumberToWords.convert(29));
    System.out.println("*** " + SpanishNumberToWords.convert(30));
    System.out.println("*** " + SpanishNumberToWords.convert(31));
    System.out.println("*** " + SpanishNumberToWords.convert(42));
    System.out.println("*** " + SpanishNumberToWords.convert(71));
    System.out.println("*** " + SpanishNumberToWords.convert(72));
    System.out.println("*** " + SpanishNumberToWords.convert(80));
    System.out.println("*** " + SpanishNumberToWords.convert(81));
    System.out.println("*** " + SpanishNumberToWords.convert(89));
    System.out.println("*** " + SpanishNumberToWords.convert(90));
    System.out.println("*** " + SpanishNumberToWords.convert(91));
    System.out.println("*** " + SpanishNumberToWords.convert(97));
    System.out.println("*** " + SpanishNumberToWords.convert(100));
    System.out.println("*** " + SpanishNumberToWords.convert(101));
    System.out.println("*** " + SpanishNumberToWords.convert(110));
    System.out.println("*** " + SpanishNumberToWords.convert(120));
    System.out.println("*** " + SpanishNumberToWords.convert(200));
    System.out.println("*** " + SpanishNumberToWords.convert(201));
    System.out.println("*** " + SpanishNumberToWords.convert(232));
    System.out.println("*** " + SpanishNumberToWords.convert(999));
    System.out.println("*** " + SpanishNumberToWords.convert(521));
    System.out.println("*** " + SpanishNumberToWords.convert(912));
    System.out.println("*** " + SpanishNumberToWords.convert(999));
    System.out.println("*** " + SpanishNumberToWords.convert(1000));
    System.out.println("*** " + SpanishNumberToWords.convert(1001));
    System.out.println("*** " + SpanishNumberToWords.convert(10000));
    System.out.println("*** " + SpanishNumberToWords.convert(10001));
    System.out.println("*** " + SpanishNumberToWords.convert(100000));
    System.out.println("*** " + SpanishNumberToWords.convert(267578));
    System.out.println("*** " + SpanishNumberToWords.convert(3000000000L));
    System.out.println("*** " + SpanishNumberToWords.convert(2147483647));
    /*
     *** OUTPUT
        *** cero
        *** un
        *** dos
        *** tres
        *** cuatro
        *** cinco
        *** siete
        *** doce
        *** dieciseis
        *** diecinueve
        *** veintiun
        *** veinticuatro
        *** veintiocho
        *** veintinueve
        *** treinta
        *** treinta y un
        *** cuarenta y dos
        *** setenta y un
        *** setenta y dos
        *** ochenta
        *** ochenta y un
        *** ochenta y nueve
        *** noventa
        *** noventa y un
        *** noventa y siete
        *** cien
        *** ciento un
        *** ciento diez
        *** ciento veinte
        *** doscientos
        *** doscientos un
        *** doscientos treinta y dos
        *** novecientos noventa y nueve
        *** quinientos veintiun
        *** novecientos doce
        *** novecientos noventa y nueve
        *** mil 
        *** mil un
        *** diez mil 
        *** diez mil un
        *** cien mil 
        *** doscientos sesenta y siete mil quinientos setenta y ocho
        *** tres mil millones 
        *** dos mil millones ciento cuarenta y siete millones cuatrocientos ochenta y tres mil seiscientos cuarenta y siete
     */
  }