Hexadecimal ('X') Format Specifier in C#

The hexadecimal ("X") format specifier in C# is used to represent a number as a hexadecimal string. The "X" or "x" format specifier is used to convert a number to a string (digit) in uppercase or lowercase hexadecimal, respectively.

C# program:

using System;

class Program
{
    static void Main()
    {
        int num1 = 255;
        int num2 = 2019;

        // Uppercase hexadecimal
        string hexUpper = num1.ToString("X");
        string hexUpperWithPadding = num2.ToString("X6");

        // Lowercase hexadecimal
        string hexLower = num1.ToString("x");
        string hexLowerWithPadding = num2.ToString("x6");

        Console.WriteLine($"Number1 in uppercase hexadecimal: {hexUpper}");
        Console.WriteLine($"Number2 in uppercase hexadecimal with padding: {hexUpperWithPadding}");

        Console.WriteLine($"Number1 in lowercase hexadecimal: {hexLower}");
        Console.WriteLine($"Number2 in lowercase hexadecimal with padding: {hexLowerWithPadding}");

        Console.ReadKey();
    }
}

Output:

Number1 in uppercase hexadecimal: FF
Number2 in uppercase hexadecimal with padding: 0007E3
Number1 in lowercase hexadecimal: ff
Number2 in lowercase hexadecimal with padding: 0007e3