How can I convert an integer into its verbal representation?

Question

Is there a library or a class/function that I can use to convert an integer to it\'s verbal representation?

Example input:

4,567,788`

Answer 1

Currently the best, most robust, library for this is definitely Humanizer. It's open sourced and available as a nuget:

Console.WriteLine(4567788.ToWords()); // => four million five hundred and sixty-seven thousand seven hundred and eighty-eight

It also has a wide range of tools solving the small problems every application has with strings, enums, DateTimes, TimeSpans and so forth, and supports many different languages.

Console.WriteLine(4567788.ToOrdinalWords().Underscore().Hyphenate().ApplyCase(LetterCasing.AllCaps)); // => FOUR-MILLION-FIVE-HUNDRED-AND-SIXTY-SEVEN-THOUSAND-SEVEN-HUNDRED-AND-EIGHTY-EIGHTH

Answer 2

Fully recursive version:

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

private static string[] tens = { "zero", "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety" };

private static string[] thous = { "hundred", "thousand", "million", "billion", "trillion", "quadrillion" };

private static string fmt_negative = "negative {0}";
private static string fmt_dollars_and_cents = "{0} dollars and {1} cents";
private static string fmt_tens_ones = "{0}-{1}"; // e.g. for twenty-one, thirty-two etc. You might want to use an en-dash or em-dash instead of a hyphen.
private static string fmt_large_small = "{0} {1}"; // stitches together the large and small part of a number, like "{three thousand} {five hundred forty two}"
private static string fmt_amount_scale = "{0} {1}"; // adds the scale to the number, e.g. "{three} {million}";

public static string ToWords(decimal number) {
    if (number < 0)
        return string.format(fmt_negative, ToWords(Math.Abs(number)));

    int intPortion = (int)number;
    int decPortion = (int)((number - intPortion) * (decimal) 100);

    return string.Format(fmt_dollars_and_cents, ToWords(intPortion), ToWords(decPortion));
}

private static string ToWords(int number, string appendScale = "") {
    string numString = "";
    // if the number is less than one hundred, then we're mostly just pulling out constants from the ones and tens dictionaries
    if (number < 100) {
        if (number < 20)
            numString = ones[number];
        else {
            numString = tens[number / 10];
            if ((number % 10) > 0)
                numString = string.Format(fmt_tens_ones, numString, ones[number % 10]);
        }
    } else {
        int pow = 0; // we'll divide the number by pow to figure out the next chunk
        string powStr = ""; // powStr will be the scale that we append to the string e.g. "hundred", "thousand", etc.

        if (number < 1000) { // number is between 100 and 1000
            pow = 100; // so we'll be dividing by one hundred
            powStr = thous[0]; // and appending the string "hundred"
        } else { // find the scale of the number
            // log will be 1, 2, 3 for 1_000, 1_000_000, 1_000_000_000, etc.
            int log = (int)Math.Log(number, 1000);
            // pow will be 1_000, 1_000_000, 1_000_000_000 etc.
            pow = (int)Math.Pow(1000, log);
            // powStr will be thousand, million, billion etc.
            powStr = thous[log];
        }

        // we take the quotient and the remainder after dividing by pow, and call ToWords on each to handle cases like "{five thousand} {thirty two}" (curly brackets added for emphasis)
        numString = string.Format(fmt_large_small, ToWords(number / pow, powStr), ToWords(number % pow)).Trim();
    }

    // and after all of this, if we were passed in a scale from above, we append it to the current number "{five} {thousand}"
    return string.Format(fmt_amount_scale, numString, appendScale).Trim();
}

Current works up to the (short scale) quadrillions. Additional support (for larger numbers, or for the long scale) can be added simply by changing the thous variable.

Answer 3

In case anyone wants a JavaScript version

Number.prototype.numberToWords = function () {
    var unitsMap = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"];
    var tensMap = ["zero", "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"];

    var num = this.valueOf();
    if (Math.round(num == 0)) {
        return "zero";
    }
    if (num < 0) {
        var positivenum = Math.abs(num);
        return "minus " + Number(positivenum).numberToWords();
    }
    var words = "";
    if (Math.floor(num / 1000000) > 0) {
        words += Math.floor(num / 1000000).numberToWords() + " million ";
        num = Math.floor(num % 1000000);
    }
    if (Math.floor(num / 1000) > 0) {
        words += Math.floor(num / 1000).numberToWords() + " thousand ";
        num = Math.floor(num % 1000);
    }
    if (Math.floor(num / 100) > 0) {
        words += Math.floor(num / 100).numberToWords() + " hundred ";
        num = Math.floor(num % 100);
    }
    if (Math.floor(num > 0)) {
        if (words != "") {
            words += "and ";
        }
        if (num < 20) {
        words += unitsMap[num];
        }
        else {
            words += tensMap[Math.floor(num / 10)];
            if ((num % 10) > 0) {
                words += "-" + unitsMap[Math.round(num % 10)];
            }
        }
    }
    return words.trim();
}

Answer 4

Solution that takes up less code.

The most important part is only couple lines:

static Func<long, string> remainder = t => t > 0 ? " " + ToEN(t) : "";

public static string ToEN(this long val, double d = 20, long th = 20)
{
    switch ((long)d)
    {
        case 20:   return val >= d ? ToEN(val, 1e2)             : en[val];
        case 100:  return val >= d ? ToEN(val, 1e3, 100)        : en[val / 10 * 10] + remainder(val % 10);
        default:   return val >= d ? ToEN(val, d * 1e3,(long)d) : ToEN(val / th) + " " + en[th] + remainder(val % th);
    }
}

Full code is available here https://dotnetfiddle.net/wjr4hF

Answer 5

Imports System.Text

Public Class NumberWriter

    Public Shared Function Parse(ByVal Number As String) As String
        If Not AreNumbers(Number) Then Return ""
        Dim TempQueue As New Queue(Of String)
        For Each ItemA As Char In Number.Replace(",", "").Reverse
            TempQueue.Enqueue(ItemA)
        Next
        Dim Blocks As New List(Of String)
        Dim BlockEmpty As New List(Of Boolean)
        Do
            Dim TempBlock As New StringBuilder(3)
            TempBlock.Append(TempQueue.Dequeue)
            If TempQueue.Count > 0 Then
                TempBlock.Append(TempQueue.Dequeue)
                If TempQueue.Count > 0 Then
                    TempBlock.Append(TempQueue.Dequeue)
                End If
            End If
            Blocks.Add(StrReverse(TempBlock.ToString))
            BlockEmpty.Add(TempBlock.ToString = "000")
            If TempQueue.Count < 1 Then Exit Do
        Loop
        Dim ResultStack As New Stack(Of String)
        For int1 As Integer = 0 To Blocks.Count - 1
            ResultStack.Push(ReadBlock(Blocks(int1)) & If(Not int1 = 0, If(Not BlockEmpty(int1), " " & CapitalizeWord(GetPlaceValueSet(int1)) & If(BlockEmpty(int1 - 1), "", ", "), ""), ""))
        Next
        Dim Result1 As String = ""
        Do Until ResultStack.Count < 1
            Result1 &= ResultStack.Pop
        Loop
        Return RemoveGrammarErrors(Result1)
    End Function

    Private Shared Function RemoveGrammarErrors(ByVal Str As String) As String
        Dim tstr As String = Str
        tstr.Replace("  ", " ")
        tstr.Replace(" , ", ", ")
        Return tstr
    End Function

    Private Shared Function AreNumbers(ByVal Str1 As String) As Boolean
        Dim Numbers() As String = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", ","}
        For Each ItemA As Char In Str1
            Dim IsN As Boolean = False
            For Each ItemB As String In Numbers
                If ItemA = ItemB Then IsN = True
            Next
            If Not IsN Then
                Return False
            End If
        Next
        Return True
    End Function

    Private Shared Function ReadBlock(ByVal Block As String)
        Select Case Block.Length
            Case 1
                Return ReadSingleDigit(Block)
            Case 2
                Return ReadTwoDigits(Block)
            Case 3
                Return ReadThreeDigits(Block)
            Case Else
                Throw New Exception
        End Select
    End Function

    Private Shared Function ReadThreeDigits(ByVal Digits As String)
        If Digits.Length > 3 Then Throw New ArgumentException("There are too many digits.")
        Dim Result As String = ""
        If Not Digits(0) = "0" Then
            Result &= ReadSingleDigit(Digits(0)) & " Hundred "
        End If
        Result &= ReadTwoDigits(Digits.Substring(1))
        Return Result
    End Function

    Private Shared Function ReadTwoDigits(ByVal Digits As String)
        If Digits.Length > 2 Then Throw New ArgumentException("There are too many digits.")
        Select Case Digits(0)
            Case "0"
                Return ReadSingleDigit(Digits(1))
            Case "1"
                Return ReadTeenNumber(Digits)
            Case Else
                Return ReadFirstInNumberPair(Digits(0)) & If(Digits(1) = "0", "", "-" & ReadSingleDigit(Digits(1)))
        End Select
    End Function

    Private Shared Function ReadSingleDigit(ByVal Digit As String) As String
        If Not Digit.Length = 1 Then Throw New ArgumentException("There must be only one digit and it must be more than zero.")
        Select Case Digit
            Case "0"
                Return ""
            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 Else
                Throw New Exception()
        End Select
    End Function

    Private Shared Function ReadTeenNumber(ByVal Num As String) As String
        Select Case Num
            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"
            Case Else
                Throw New Exception()
        End Select
    End Function

    Private Shared Function ReadFirstInNumberPair(ByVal Num As String) As String
        If Not (Num > 1 OrElse Num < 10) Then Throw New ArgumentException("Number must be more than 1 and less than 10")
        Select Case Num
            Case "2"
                Return "Twenty"
            Case "3"
                Return "Thirty"
            Case "4"
                Return "Fourty"
            Case "5"
                Return "Fifty"
            Case "6"
                Return "Sixty"
            Case "7"
                Return "Seventy"
            Case "8"
                Return "Eighty"
            Case "9"
                Return "Ninety"
            Case Else
                Throw New Exception()
        End Select
    End Function

    Private Shared Function CapitalizeWord(ByVal Word As String) As String
        Return Word.Substring(0, 1).ToUpper & Word.Substring(1)
    End Function

    Private Shared Function GetPlaceValueSet(ByVal Num As Byte) As String
        Select Case Num
            Case 0
                Return "" 'Hundreds
            Case 1
                Return "Thousand"
            Case 2
                Return "Million"
            Case 3
                Return "Billion"
            Case 4
                Return "Trillion"
            Case 5
                Return "Quadrillion"
            Case 6
                Return "Quintillion"
            Case 7
                Return "Sextillion"
            Case 8
                Return "Septillion"
            Case 9
                Return "Octillion"
            Case 10
                Return "Nonillion"
            Case 11
                Return "octillion"
            Case 12
                Return "nonillion"
            Case 13
                Return "decillion"
            Case 14
                Return "undecillion"
            Case 15
                Return "dodecillion,"
            Case 16
                Return "tredecillion"
            Case 17
                Return "quattuordecillion"
            Case 18
                Return "quindecillion"
            Case 19
                Return "sexdecillion"
            Case 20
                Return "septendecillion"
            Case 21
                Return "octodecillion"
            Case 22
                Return "novemdecillion"
            Case 23
                Return "vigintillion"
            Case 24
                Return "unvigintillion"
            Case 25
                Return "dovigintillion"
            Case 26
                Return "trevigintillion"
            Case 27
                Return "quattuorvigintillion"
            Case 28
                Return "quinvigintillion"
            Case 29
                Return "sexvigintillion"
            Case 30
                Return "septenvigintillion"
            Case 31
                Return "octovigintillion"
            Case 32
                Return "novemvigintillion"
            Case 33
                Return "trigintillion"
            Case 34
                Return "untrigintillion"
            Case 35
                Return "dotrigintillion"
            Case 36
                Return "tretrigintillion"
            Case 37
                Return "quattuortrigintillion"
            Case 38
                Return "quintrigintillion"
            Case 39
                Return "sextrigintillion"
            Case 40
                Return "septentrigintillion"
            Case 41
                Return "octotrigintillion"
            Case Else
                Throw New Exception
        End Select
    End Function
End Class

Sorry it's in VB.NET, but it works completely. It is one way. Number to Verbal. Handles numbers up to 123 characters long I believe.

Answer 6

The following C# console app code will give accepts a monetary value in numbers up to 2 decimals and prints it in English. You can use it as a reference to achieve your results.

   namespace ConsoleApplication2
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text.RegularExpressions;
    class Program
    {
       static void Main(string[] args)
        {
            bool repeat = true;
            while (repeat)
            {
                string inputMonetaryValueInNumberic = string.Empty;
                string centPart = string.Empty;
                string dollarPart = string.Empty;
                Console.Write("\nEnter the monetary value : ");
                inputMonetaryValueInNumberic = Console.ReadLine();
                inputMonetaryValueInNumberic = inputMonetaryValueInNumberic.TrimStart('0');

                if (ValidateInput(inputMonetaryValueInNumberic))
                {

                    if (inputMonetaryValueInNumberic.Contains('.'))
                    {
                        centPart = ProcessCents(inputMonetaryValueInNumberic.Substring(inputMonetaryValueInNumberic.IndexOf(".") + 1));
                        dollarPart = ProcessDollar(inputMonetaryValueInNumberic.Substring(0, inputMonetaryValueInNumberic.IndexOf(".")));
                    }
                    else
                    {
                        dollarPart = ProcessDollar(inputMonetaryValueInNumberic);
                    }
                    centPart = string.IsNullOrWhiteSpace(centPart) ? string.Empty : " and " + centPart;
                    Console.WriteLine(string.Format("\n\n{0}{1}", dollarPart, centPart));
                }
                else
                {
                    Console.WriteLine("Invalid Input..");
                }

                Console.WriteLine("\n\nPress any key to continue or Escape of close : ");
                var loop = Console.ReadKey();
                repeat = !loop.Key.ToString().Contains("Escape");
                Console.Clear();
            }

        }

        private static string ProcessCents(string cents)
        {
            string english = string.Empty;
            string dig3 = Process3Digit(cents);
            if (!string.IsNullOrWhiteSpace(dig3))
            {
                dig3 = string.Format("{0} {1}", dig3, GetSections(0));
            }
            english = dig3 + english;
            return english;
        }
        private static string ProcessDollar(string dollar)
        {
            string english = string.Empty;
            foreach (var item in Get3DigitList(dollar))
            {
                string dig3 = Process3Digit(item.Value);
                if (!string.IsNullOrWhiteSpace(dig3))
                {
                    dig3 = string.Format("{0} {1}", dig3, GetSections(item.Key));
                }
                english = dig3 + english;
            }
            return english;
        }
        private static string Process3Digit(string digit3)
        {
            string result = string.Empty;
            if (Convert.ToInt32(digit3) != 0)
            {
                int place = 0;
                Stack<string> monetaryValue = new Stack<string>();
                for (int i = digit3.Length - 1; i >= 0; i--)
                {
                    place += 1;
                    string stringValue = string.Empty;
                    switch (place)
                    {
                        case 1:
                            stringValue = GetOnes(digit3[i].ToString());
                            break;
                        case 2:
                            int tens = Convert.ToInt32(digit3[i]);
                            if (tens == 1)
                            {
                                if (monetaryValue.Count > 0)
                                {
                                    monetaryValue.Pop();
                                }
                                stringValue = GetTens((digit3[i].ToString() + digit3[i + 1].ToString()));
                            }
                            else
                            {
                                stringValue = GetTens(digit3[i].ToString());
                            }
                            break;
                        case 3:
                            stringValue = GetOnes(digit3[i].ToString());
                            if (!string.IsNullOrWhiteSpace(stringValue))
                            {
                                string postFixWith = " Hundred";
                                if (monetaryValue.Count > 0)
                                {
                                    postFixWith = postFixWith + " And";
                                }
                                stringValue += postFixWith;
                            }
                            break;
                    }
                    if (!string.IsNullOrWhiteSpace(stringValue))
                        monetaryValue.Push(stringValue);
                }
                while (monetaryValue.Count > 0)
                {
                    result += " " + monetaryValue.Pop().ToString().Trim();
                }
            }
            return result;
        }
        private static Dictionary<int, string> Get3DigitList(string monetaryValueInNumberic)
        {
            Dictionary<int, string> hundredsStack = new Dictionary<int, string>();
            int counter = 0;
            while (monetaryValueInNumberic.Length >= 3)
            {
                string digit3 = monetaryValueInNumberic.Substring(monetaryValueInNumberic.Length - 3, 3);
                monetaryValueInNumberic = monetaryValueInNumberic.Substring(0, monetaryValueInNumberic.Length - 3);
                hundredsStack.Add(++counter, digit3);
            }
            if (monetaryValueInNumberic.Length != 0)
                hundredsStack.Add(++counter, monetaryValueInNumberic);
            return hundredsStack;
        }
        private static string GetTens(string tensPlaceValue)
        {
            string englishEquvalent = string.Empty;
            int value = Convert.ToInt32(tensPlaceValue);
            Dictionary<int, string> tens = new Dictionary<int, string>();
            tens.Add(2, "Twenty");
            tens.Add(3, "Thirty");
            tens.Add(4, "Forty");
            tens.Add(5, "Fifty");
            tens.Add(6, "Sixty");
            tens.Add(7, "Seventy");
            tens.Add(8, "Eighty");
            tens.Add(9, "Ninty");
            tens.Add(10, "Ten");
            tens.Add(11, "Eleven");
            tens.Add(12, "Twelve");
            tens.Add(13, "Thrteen");
            tens.Add(14, "Fourteen");
            tens.Add(15, "Fifteen");
            tens.Add(16, "Sixteen");
            tens.Add(17, "Seventeen");
            tens.Add(18, "Eighteen");
            tens.Add(19, "Ninteen");
            if (tens.ContainsKey(value))
            {
                englishEquvalent = tens[value];
            }

            return englishEquvalent;

        }
        private static string GetOnes(string onesPlaceValue)
        {
            int value = Convert.ToInt32(onesPlaceValue);
            string englishEquvalent = string.Empty;
            Dictionary<int, string> ones = new Dictionary<int, string>();
            ones.Add(1, " One");
            ones.Add(2, " Two");
            ones.Add(3, " Three");
            ones.Add(4, " Four");
            ones.Add(5, " Five");
            ones.Add(6, " Six");
            ones.Add(7, " Seven");
            ones.Add(8, " Eight");
            ones.Add(9, " Nine");

            if (ones.ContainsKey(value))
            {
                englishEquvalent = ones[value];
            }

            return englishEquvalent;
        }
        private static string GetSections(int section)
        {
            string sectionName = string.Empty;
            switch (section)
            {
                case 0:
                    sectionName = "Cents";
                    break;
                case 1:
                    sectionName = "Dollars";
                    break;
                case 2:
                    sectionName = "Thousand";
                    break;
                case 3:
                    sectionName = "Million";
                    break;
                case 4:
                    sectionName = "Billion";
                    break;
                case 5:
                    sectionName = "Trillion";
                    break;
                case 6:
                    sectionName = "Zillion";
                    break;
            }
            return sectionName;
        }
        private static bool ValidateInput(string input)
        {
            return Regex.IsMatch(input, "[0-9]{1,18}(\\.[0-9]{1,2})?"))
        }
    }
}