Convert Double to a Word (not string)

In C#, there is no built-in method to directly convert a Double value to its textual representation in words. However, you can achieve this by breaking down the number into its individual parts (thousands, hundreds, tens, and units) and then converting each part to its corresponding word representation.

Here's an example of how you can accomplish this using C#:

public static string ConvertDoubleToText(double number)
{
    string[] units = { "", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine" };
    string[] teens = { "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
    string[] tens = { "", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };

    if (number == 0)
    {
        return "Zero";
    }

    string words = "";

    if (number < 0)
    {
        words += "Minus ";
        number = Math.Abs(number);
    }

    int intPart = (int)number;
    int decimalPart = (int)((number - intPart) * 100);

    if (intPart > 0)
    {
        words += ConvertToWords(intPart) + " ";
    }

    if (decimalPart > 0)
    {
        words += "and " + ConvertToWords(decimalPart);
    }

    return words.Trim();
}

private static string ConvertToWords(int number)
{
    if (number < 10)
    {
        return units[number];
    }
    else if (number < 20)
    {
        return teens[number - 10];
    }
    else if (number < 100)
    {
        return tens[number / 10] + " " + units[number % 10];
    }
    else if (number < 1000)
    {
        return units[number / 100] + " Hundred " + ConvertToWords(number % 100);
    }
    else if (number < 1000000)
    {
        return ConvertToWords(number / 1000) + " Thousand " + ConvertToWords(number % 1000);
    }
    else if (number < 1000000000)
    {
        return ConvertToWords(number / 1000000) + " Million " + ConvertToWords(number % 1000000);
    }
    else
    {
        return ConvertToWords(number / 1000000000) + " Billion " + ConvertToWords(number % 1000000000);
    }
}

You can use the ConvertDoubleToText method to convert a Double value to its textual representation. For example:

double number = 1200;
string text = ConvertDoubleToText(number);
Console.WriteLine(text); // Output: "One Thousand Two Hundred"

Please note that this implementation is limited to converting numbers up to billions. You can modify it to support larger numbers if needed.

I hope this helps! Let me know if you have any further questions.

Use the below Function 

public static class NumberToWordsConverter
{
    private static readonly string[] Ones =
    {
        "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"
    };

    private static readonly string[] Teens =
    {
        "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"
    };

    private static readonly string[] Tens =
    {
        "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"
    };

    private static readonly string[] Thousands = { "", "Thousand", "Million", "Billion", "Trillion" };

    public static string ConvertToWords(double number)
    {
        if (number == 0)
            return Ones[0];

        string words = "";

        int i = 0;
        while (number > 0)
        {
            if (number % 1000 != 0)
            {
                words = $"{ConvertChunk((int)(number % 1000))} {Thousands[i]} {words}";
            }
            number /= 1000;
            i++;
        }

        return words.Trim();
    }

    private static string ConvertChunk(int number)
    {
        string chunk = "";

        if (number >= 100)
        {
            chunk += $"{Ones[number / 100]} Hundred ";
            number %= 100;
        }

        if (number >= 10 && number <= 19)
        {
            chunk += Teens[number - 10];
        }
        else if (number >= 20)
        {
            chunk += $"{Tens[number / 10 - 2]} ";
            number %= 10;
        }

        if (number >= 1 && number <= 9)
        {
            chunk += Ones[number];
        }

        return chunk;
    }
}

Public void Convert()

{
double  Number = 1234567.89; // Replace this with your double value
string result = NumberToWordsConverter.ConvertToWords(Number );

}

using System;
using System.Text;

public class Program
{
    static void Main()
    {
        double number = 1200.00;
        string words = ConvertDoubleToWords(number);
        Console.WriteLine(words); // Output: "One Thousand Two Hundred"
    }

    public static string ConvertDoubleToWords(double number)
    {
        // Split the double into integer and fractional parts
        long integerPart = (long)number;
        double fractionalPart = number - integerPart;

        // Convert the integer part to words
        string integerWords = ConvertToWords(integerPart);

        // Convert the fractional part to words
        string fractionalWords = ConvertFractionToWords(fractionalPart);

        // Combine the integer and fractional parts
        StringBuilder result = new StringBuilder();
        result.Append(integerWords);

        if (!string.IsNullOrEmpty(fractionalWords))
        {
            result.Append(" and ");
            result.Append(fractionalWords);
        }

        return result.ToString();
    }

    public static string ConvertToWords(long number)
    {
        // Define the word equivalents for digits
        string[] units = { "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine" };
        string[] teens = { "", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
        string[] tens = { "", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };
        string[] thousands = { "", "Thousand", "Million", "Billion", "Trillion" };

        int groupIndex = 0;
        string words = "";

        while (number > 0)
        {
            long group = number % 1000;
            if (group > 0)
            {
                string groupWords = "";

                if (group >= 100)
                {
                    groupWords += units[group / 100] + " Hundred";
                    group %= 100;
                    if (group > 0)
                        groupWords += " and ";
                }

                if (group >= 20)
                {
                    groupWords += tens[group / 10];
                    group %= 10;
                    if (group > 0)
                        groupWords += " ";
                }

                if (group > 10 && group < 20)
                {
                    groupWords += teens[group - 10];
                    group = 0;
                }

                if (group > 0)
                {
                    groupWords += units[group];
                }

                words = groupWords + " " + thousands[groupIndex] + " " + words;
            }

            number /= 1000;
            groupIndex++;
        }

        return words.Trim();
    }

    public static string ConvertFractionToWords(double fractionalPart)
    {
        // Limit the precision of the fractional part to two decimal places
        fractionalPart = Math.Round(fractionalPart, 2);

        if (fractionalPart == 0)
        {
            return ""; // No fractional part
        }

        // Extract the fractional part as two digits
        int fractionalDigits = (int)(fractionalPart * 100);

        // Convert the two digits to words
        string fractionalWords = ConvertToWords(fractionalDigits);

        // Add "Cents" or "Cent" at the end
        return fractionalWords + (fractionalDigits == 1 ? " Cent" : " Cents");
    }
}

This is not the perfact solutions, but it will work for you:

namespace MyConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            double number = 1.200;
            string numberAsString = number.ToString("F3"); // Convert the double to a string with 3 decimal places
            string numberWithoutDot = numberAsString.Replace(".", ""); // Remove the dot
            int number1 = int.Parse(numberWithoutDot);
            string result = NumbersToWords.ConvertNumber(number1);
            Console.WriteLine(result);
        }
    }

    class NumbersToWords
    {
        private static readonly string[] units = { "Zero", "One", "Two", "Three",
        "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven",
        "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen",
        "Seventeen", "Eighteen", "Nineteen" };
        private static readonly string[] tens = { "", "", "Twenty", "Thirty", "Forty",
        "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };

        public static string ConvertNumber(double dblNumber)
        {
            try
            {
                long intNumber = (long)dblNumber;
                long decNumber = (long)Math.Round((dblNumber - intNumber) * 100);
                if (decNumber == 0)
                {
                    return Convert(intNumber);
                }
                else
                {
                    return Convert(intNumber) + " Point " + Convert(decNumber);
                }
            }
            catch (Exception e)
            {
                // TODO: handle exception
                Debug.WriteLine(e.Message);
            }
            return "";
        }

        internal static string Convert(long i)
        {
            if (i < 20)
            {
                return units[i];
            }
            if (i < 100)
            {
                return tens[i / 10] + ((i % 10 > 0) ? " " + Convert(i % 10) : "");
            }
            if (i < 1000)
            {
                return units[i / 100] + " Hundred"
                        + ((i % 100 > 0) ? " And " + Convert(i % 100) : "");
            }
            if (i < 100000)
            {
                return Convert(i / 1000) + " Thousand "
                + ((i % 1000 > 0) ? " " + Convert(i % 1000) : "");
            }
            if (i < 10000000)
            {
                return Convert(i / 100000) + " Lakh "
                        + ((i % 100000 > 0) ? " " + Convert(i % 100000) : "");
            }
            if (i < 1000000000)
            {
                return Convert(i / 10000000) + " Crore "
                        + ((i % 10000000 > 0) ? " " + Convert(i % 10000000) : "");
            }
            return Convert(i / 1000000000) + " Arab "
                    + ((i % 1000000000 > 0) ? " " + Convert(i % 1000000000) : "");
        }
    }
}

Hi,

An article on the same topic was authored by a member of the C# Corner community - https://www.c-sharpcorner.com/blogs/convert-number-to-words-in-c-sharp

Similar thread in Stack Overflow - https://stackoverflow.com/questions/2729752/converting-numbers-in-to-words-c-sharp