C# Program to convert Digits to Words

Converting digits to words in C# involves breaking down a number into its individual digits and mapping each digit to its corresponding word representation. This technique is commonly used in financial applications, report generation, and number-to-text conversion systems.

Algorithm Overview

The conversion process follows these steps −

• Create an array of word strings for digits 0-9

• Extract each digit from the number using modulo operation

• Store digits in reverse order (rightmost digit first)

• Map each digit to its corresponding word and display in correct order

Basic Implementation

Here's a simple approach to convert digits to words −

using System;

class DigitToWords {
    static void Main(string[] args) {
        int val, next, num_digits;
        int[] a = new int[10];
        
        // words for every digits from 0 to 9
        string[] digits_words = {
            "zero", "one", "two", "three", "four",
            "five", "six", "seven", "eight", "nine"
        };
        
        // number to be converted into words
        val = 4677;
        Console.WriteLine("Number: " + val);
        Console.Write("Number (words): ");
        
        next = 0;
        num_digits = 0;
        
        // extract digits and store in reverse order
        do {
            next = val % 10;
            a[num_digits] = next;
            num_digits++;
            val = val / 10;
        } while (val > 0);
        
        // display words in correct order
        num_digits--;
        for (; num_digits >= 0; num_digits--)
            Console.Write(digits_words[a[num_digits]] + " ");
    }
}

The output of the above code is −

Number: 4677
Number (words): four six seven seven 

Using String-Based Approach

An alternative method using string manipulation for better readability −

using System;

class StringDigitConverter {
    static void Main(string[] args) {
        string[] digitWords = {
            "zero", "one", "two", "three", "four",
            "five", "six", "seven", "eight", "nine"
        };
        
        int number = 2534;
        Console.WriteLine("Number: " + number);
        
        string numberStr = number.ToString();
        Console.Write("Number (words): ");
        
        foreach (char digit in numberStr) {
            int digitValue = digit - '0';
            Console.Write(digitWords[digitValue] + " ");
        }
        Console.WriteLine();
    }
}

The output of the above code is −

Number: 2534
Number (words): two five three four 

Method-Based Implementation

A more organized approach using separate methods −

using System;

class DigitWordConverter {
    static string[] digitWords = {
        "zero", "one", "two", "three", "four",
        "five", "six", "seven", "eight", "nine"
    };
    
    static string ConvertDigitsToWords(int number) {
        if (number == 0) return "zero";
        
        string result = "";
        string numStr = number.ToString();
        
        foreach (char digit in numStr) {
            int digitValue = digit - '0';
            result += digitWords[digitValue] + " ";
        }
        
        return result.Trim();
    }
    
    static void Main(string[] args) {
        int[] testNumbers = { 123, 4056, 789, 0 };
        
        foreach (int num in testNumbers) {
            Console.WriteLine($"Number: {num}");
            Console.WriteLine($"Words: {ConvertDigitsToWords(num)}");
            Console.WriteLine();
        }
    }
}

The output of the above code is −

Number: 123
Words: one two three

Number: 4056
Words: four zero five six

Number: 789
Words: seven eight nine

Number: 0
Words: zero

Key Points

• The modulo operator (%) extracts the rightmost digit

• Integer division (/) removes the rightmost digit

• Digits are processed in reverse order, so they need to be stored and then displayed in correct sequence

• String conversion approach is simpler but may be less efficient for very large numbers

Conclusion

Converting digits to words in C# can be accomplished through mathematical digit extraction or string manipulation. The mathematical approach provides better understanding of number processing, while the string-based method offers cleaner, more readable code for most practical applications.