How to Convert Number to Ordinal in C#?

Ordinal numbers typically end in "st", "nd", "rd", or "th" depending on the last digit of the number.

To convert a number to its ordinal form in C#, we can create a simple function that takes an integer as input and returns the corresponding ordinal string. 

using System;

class Program
{
    static string ConvertToOrdinal(int number)
    {
        if (number <= 0)
            return number.ToString();

        switch (number % 100)
        {
            case 11:
            case 12:
            case 13:
                return number + "th";
        }

        switch (number % 10)
        {
            case 1:
                return number + "st";
            case 2:
                return number + "nd";
            case 3:
                return number + "rd";
            default:
                return number + "th";
        }
    }

    static void Main(string[] args)
    {
        // Example usage
        for (int i = 1; i <= 10; i++)
        {
            Console.WriteLine($"{i} -> {ConvertToOrdinal(i)}");
        }
    }
}

Output:

1 -> 1st

2 -> 2nd

3 -> 3rd

4 -> 4th

5 -> 5th

6 -> 6th

7 -> 7th

8 -> 8th

9 -> 9th

10 -> 10th