math - 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. But we are running into issues for numbers which are huge.

10183 = Ten thousand one hundred eighty three
90 = Ninety
5888 = Five thousand eight hundred eighty eight

Is there an easy to use function in any of the math libraries which I can use for this purpose?

Answer 1

Here is the code, I don't think there is any method in SE.

It basically converts number to string and parses String and associates it with the weight

for example

1000

1 is treated as thousand position and 1 gets mapped to "one" and thousand because of position

This is the code from the website:

English

import java.text.DecimalFormat;

public class EnglishNumberToWords {

  private static final String[] tensNames = {
    "",
    " ten",
    " twenty",
    " thirty",
    " forty",
    " fifty",
    " sixty",
    " seventy",
    " eighty",
    " ninety"
  };

  private static final String[] numNames = {
    "",
    " one",
    " two",
    " three",
    " four",
    " five",
    " six",
    " seven",
    " eight",
    " nine",
    " ten",
    " eleven",
    " twelve",
    " thirteen",
    " fourteen",
    " fifteen",
    " sixteen",
    " seventeen",
    " eighteen",
    " nineteen"
  };

  private EnglishNumberToWords() {}

  private static String convertLessThanOneThousand(int number) {
    String soFar;

    if (number % 100 < 20){
      soFar = numNames[number % 100];
      number /= 100;
    }
    else {
      soFar = numNames[number % 10];
      number /= 10;

      soFar = tensNames[number % 10] + soFar;
      number /= 10;
    }
    if (number == 0) return soFar;
    return numNames[number] + " hundred" + soFar;
  }


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

    String snumber = Long.toString(number);

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

    // XXXnnnnnnnnn
    int billions = Integer.parseInt(snumber.substring(0,3));
    // nnnXXXnnnnnn
    int millions  = Integer.parseInt(snumber.substring(3,6));
    // nnnnnnXXXnnn
    int hundredThousands = Integer.parseInt(snumber.substring(6,9));
    // nnnnnnnnnXXX
    int thousands = Integer.parseInt(snumber.substring(9,12));

    String tradBillions;
    switch (billions) {
    case 0:
      tradBillions = "";
      break;
    case 1 :
      tradBillions = convertLessThanOneThousand(billions)
      + " billion ";
      break;
    default :
      tradBillions = convertLessThanOneThousand(billions)
      + " billion ";
    }
    String result =  tradBillions;

    String tradMillions;
    switch (millions) {
    case 0:
      tradMillions = "";
      break;
    case 1 :
      tradMillions = convertLessThanOneThousand(millions)
         + " million ";
      break;
    default :
      tradMillions = convertLessThanOneThousand(millions)
         + " million ";
    }
    result =  result + tradMillions;

    String tradHundredThousands;
    switch (hundredThousands) {
    case 0:
      tradHundredThousands = "";
      break;
    case 1 :
      tradHundredThousands = "one thousand ";
      break;
    default :
      tradHundredThousands = convertLessThanOneThousand(hundredThousands)
         + " thousand ";
    }
    result =  result + tradHundredThousands;

    String tradThousand;
    tradThousand = convertLessThanOneThousand(thousands);
    result =  result + tradThousand;

    // remove extra spaces!
    return result.replaceAll("^\s+", "").replaceAll("\b\s{2,}\b", " ");
  }

  /**
   * testing
   * @param args
   */
  public static void main(String[] args) {
    System.out.println("*** " + EnglishNumberToWords.convert(0));
    System.out.println("*** " + EnglishNumberToWords.convert(1));
    System.out.println("*** " + EnglishNumberToWords.convert(16));
    System.out.println("*** " + EnglishNumberToWords.convert(100));
    System.out.println("*** " + EnglishNumberToWords.convert(118));
    System.out.println("*** " + EnglishNumberToWords.convert(200));
    System.out.println("*** " + EnglishNumberToWords.convert(219));
    System.out.println("*** " + EnglishNumberToWords.convert(800));
    System.out.println("*** " + EnglishNumberToWords.convert(801));
    System.out.println("*** " + EnglishNumberToWords.convert(1316));
    System.out.println("*** " + EnglishNumberToWords.convert(1000000));
    System.out.println("*** " + EnglishNumberToWords.convert(2000000));
    System.out.println("*** " + EnglishNumberToWords.convert(3000200));
    System.out.println("*** " + EnglishNumberToWords.convert(700000));
    System.out.println("*** " + EnglishNumberToWords.convert(9000000));
    System.out.println("*** " + EnglishNumberToWords.convert(9001000));
    System.out.println("*** " + EnglishNumberToWords.convert(123456789));
    System.out.println("*** " + EnglishNumberToWords.convert(2147483647));
    System.out.println("*** " + EnglishNumberToWords.convert(3000000010L));

    /*
     *** zero
     *** one
     *** sixteen
     *** one hundred
     *** one hundred eighteen
     *** two hundred
     *** two hundred nineteen
     *** eight hundred
     *** eight hundred one
     *** one thousand three hundred sixteen
     *** one million
     *** two millions
     *** three millions two hundred
     *** seven hundred thousand
     *** nine millions
     *** nine millions one thousand
     *** one hundred twenty three millions four hundred
     **      fifty six thousand seven hundred eighty nine
     *** two billion one hundred forty seven millions
     **      four hundred eighty three thousand six hundred forty seven
     *** three billion ten
     **/
  }
}

Fran?ais Quite different than the english version but french is a lot more difficult!

package com.rgagnon.howto;

import java.text.*;

class FrenchNumberToWords {
  private static final String[] dizaineNames = {
    "",
    "",
    "vingt",
    "trente",
    "quarante",
    "cinquante",
    "soixante",
    "soixante",
    "quatre-vingt",
    "quatre-vingt"
  };

  private static final String[] uniteNames1 = {
    "",
    "un",
    "deux",
    "trois",
    "quatre",
    "cinq",
    "six",
    "sept",
    "huit",
    "neuf",
    "dix",
    "onze",
    "douze",
    "treize",
    "quatorze",
    "quinze",
    "seize",
    "dix-sept",
    "dix-huit",
    "dix-neuf"
  };

  private static final String[] uniteNames2 = {
    "",
    "",
    "deux",
    "trois",
    "quatre",
    "cinq",
    "six",
    "sept",
    "huit",
    "neuf",
    "dix"
  };

  private FrenchNumberToWords() {}

  private static String convertZeroToHundred(int number) {

    int laDizaine = number / 10;
    int lUnite = number % 10;
    String resultat = "";

    switch (laDizaine) {
    case 1 :
    case 7 :
    case 9 :
      lUnite = lUnite + 10;
      break;
    default:
    }

    // séparateur "-" "et"  ""
    String laLiaison = "";
    if (laDizaine > 1) {
      laLiaison = "-";
    }
    // cas particuliers
    switch (lUnite) {
    case 0:
      laLiaison = "";
      break;
    case 1 :
      if (laDizaine == 8) {
        laLiaison = "-";
      }
      else {
        laLiaison = " et ";
      }
      break;
    case 11 :
      if (laDizaine==7) {
        laLiaison = " et ";
      }
      break;
    default:
    }

    // dizaines en lettres
    switch (laDizaine) {
    case 0:
      resultat = uniteNames1[lUnite];
      break;
    case 8 :
      if (lUnite == 0) {
        resultat = dizaineNames[laDizaine];
      }
      else {
        resultat = dizaineNames[laDizaine]
                                + laLiaison + uniteNames1[lUnite];
      }
      break;
    default :
      resultat = dizaineNames[laDizaine]
                              + laLiaison + uniteNames1[lUnite];
    }
    return resultat;
  }

  private static String convertLessThanOneThousand(int number) {

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

    String resultat;
    switch (lesCentaines) {
    case 0:
      resultat = sReste;
      break;
    case 1 :
      if (leReste > 0) {
        resultat = "cent " + sReste;
      }
      else {
        resultat = "cent";
      }
      break;
    default :
      if (leReste > 0) {
        resultat = uniteNames2[lesCentaines] + " cent " + sReste;
      }
      else {
        resultat = uniteNames2[lesCentaines] + " cents";
      }
    }
    return resultat;
  }

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

    String snumber = Long.toString(number);

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

    // XXXnnnnnnnnn
    int lesMilliards = Integer.parseInt(snumber.substring(0,3));
    // nnnXXXnnnnnn
    int lesMillions  = Integer.parseInt(snumber.substring(3,6));
    // nnnnnnXXXnnn
    int lesCentMille = Integer.parseInt(snumber.substring(6,9));
    // nnnnnnnnnXXX
    int lesMille = Integer.parseInt(snumber.substring(9,12));

    String tradMilliards;
    switch (lesMilliards) {
    case 0:
      tradMilliards = "";
      break;
    case 1 :
      tradMilliards = convertLessThanOneThousand(lesMilliards)
         + " milliard ";
      break;
    default :
      tradMilliards = convertLessThanOneThousand(lesMilliards)
         + " milliards ";
    }
    String resultat =  tradMilliards;

    String tradMillions;
    switch (lesMillions) {
    case 0:
      tradMillions = "";
      break;
    case 1 :
      tradMillions = convertLessThanOneThousand(lesMillions)
         + " million ";
      break;
    default :
      tradMillions = convertLessThanOneThousand(lesMillions)
         + " millions ";
    }
    resultat =  resultat + tradMillions;

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

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

    return resultat;
  }

  public static void main(String[] args) {
    System.out.println("*** " + FrenchNumberToWords.convert(0));
    System.out.println("*** " + FrenchNumberToWords.convert(9));
    System.out.println("*** " + FrenchNumberToWords.convert(19));
    System.out.println("*** " + FrenchNumberToWords.convert(21));
    System.out.println("*** " + FrenchNumberToWords.convert(28));
    System.out.println("*** " + FrenchNumberToWords.convert(71));
    System.out.println("*** " + FrenchNumberToWords.convert(72));
    System.out.println("*** " + FrenchNumberToWords.convert(80));
    System.out.println("*** " + FrenchNumberToWords.convert(81));
    System.out.println("*** " + FrenchNumberToWords.convert(89));
    System.out.println("*** " + FrenchNumberToWords.convert(90));
    System.out.println("*** " + FrenchNumberToWords.convert(91));
    System.out.println("*** " + FrenchNumberToWords.convert(97));
    System.out.println("*** " + FrenchNumberToWords.convert(100));
    System.out.println("*** " + FrenchNumberToWords.convert(101));
    System.out.println("*** " + FrenchNumberToWords.convert(110));
    System.out.println("*** " + FrenchNumberToWords.convert(120));
    System.out.println("*** " + FrenchNumberToWords.convert(200));
    System.out.println("*** " + FrenchNumberToWords.convert(201));
    System.out.pri