Question

Write a program that accepts a number and outputs its equivalent in words.
Ex. Enter a number: 1380 Output: One Thousand Three Hundred Eighty
Note: The maximum input number is 3000

Solution 1: if / else if / else conditional statement
Solution 2: switch / case conditional statement

Answer 1

using System;

namespace NumberToWords

{
    public class NumberToWordsConverter
    {
        private string[] numbers = { "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
        private string[] tens = { "", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };
        public NumberToWordsConverter()
        {
        }
        public string ConvertToStringWithIf(int number)
        {
            char[] digits = number.ToString().ToCharArray();
            string words = null;
            if (number >= 0 && number <= 19)
            {
                words = words + numbers[number];
            }
            else if (number >= 20 && number <= 99)
            {
                int firstDigit = (int)char.GetNumericValue(digits[0]);
                int secondPart = number % 10;
                words = words + tens[firstDigit - 1]; // Adjusted index for tens array
                if (secondPart > 0)
                {
                    words = words + " " + ConvertToStringWithIf(secondPart);
                }
            }
            else if (number >= 100 && number <= 999)
            {
                int firstDigit = (int)char.GetNumericValue(digits[0]);
                int secondPart = number % 100;
                words = words + numbers[firstDigit] + " hundred";
                if (secondPart > 0)
                {
                    words = words + " and " + ConvertToStringWithIf(secondPart);
                }
            }
            else if (number >= 1000 && number <= 3000)
            {
                int firstPart = (int)char.GetNumericValue(digits[0]);
                if (number >= 10000)
                {
                    string twoDigits = digits[0].ToString() + digits[1].ToString();
                    firstPart = Convert.ToInt16(twoDigits);
                }
                int secondPart = number % 1000;
                words = words + numbers[firstPart] + " thousand";
                if (secondPart > 0 && secondPart <= 99)
                {
                    words = words + " and " + ConvertToStringWithIf(secondPart);
                }
                else if (secondPart >= 100)
                {
                    words = words + " " + ConvertToStringWithIf(secondPart);
                }
            }
            return words;
        }
        public string ConvertToStringWithSwitch(int number)
        {
            char[] digits = number.ToString().ToCharArray();
            string words = null;
            int digitCount = (int)Math.Log10(number) + 1;
            switch (digitCount)
            {
                case 1:
                    words = words + numbers[number];
                    break;
                case 2:
                    int firstDigit = (int)char.GetNumericValue(digits[0]);
                    int secondPart = number % 10;
                    words = words + tens[firstDigit - 1]; // Adjusted index for tens array
                    if (secondPart > 0)
                    {
                        words = words + " " + ConvertToStringWithSwitch(secondPart);
                    }
                    break;
                case 3:
                    firstDigit = (int)char.GetNumericValue(digits[0]);
                    secondPart = number % 100;
                    words = words + numbers[firstDigit] + " hundred";
                    if (secondPart > 0)
                    {
                        words = words + " and " + ConvertToStringWithSwitch(secondPart);
                    }
                    break;
                case 4:
                    int firstPart = (int)char.GetNumericValue(digits[0]);
                    if (number >= 10000)
                    {
                        string twoDigits = digits[0].ToString() + digits[1].ToString();
                        firstPart = Convert.ToInt16(twoDigits);
                    }
                    secondPart = number % 1000;
                    words = words + numbers[firstPart] + " thousand";
                    if (secondPart > 0 && secondPart <= 99)
                    {
                        words = words + " and " + ConvertToStringWithSwitch(secondPart);
                    }
                    else if (secondPart >= 100)
                    {
                        words = words + " " + ConvertToStringWithSwitch(secondPart);
                    }
                    break;
            }
            return words;
        }
    }
}