using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        string filter = null;

        string[] files = new string[] { "file1.TXT", "file2.txt", "file3.txt", "file4.txt", "file5.xls", "file6.xlxs", "file7.xlsx" };

        if (System.String.IsNullOrEmpty(filter) || filter == "*" || filter == ".*" || filter == ".*")

        {

            filter = ".*";

        }

        else

        {

            filter = filter.Replace("*", "").Replace(".", "");  

        }

        //Regex rgx = new Regex(@".*\." + filter + "?$", RegexOptions.IgnoreCase);

        Regex rgx = new Regex(@"(.*?)\.(" + filter + ")$", RegexOptions.IgnoreCase);

        foreach(string item in files)

        {

            if (rgx.IsMatch(item))

            {

                Console.WriteLine(item + " is " + filter);

            }   

        }

        string color = "red";

        int id = 5;

        color = (id == 1 || id == 4) ? "green" : "red";

        Console.WriteLine("The color = {0}", color);

        Console.WriteLine("----------------------");

        // Compare Dates

        DateTime StartDate = new DateTime(2022, 8, 1, 0, 0, 0);

        DateTime EndDate = new DateTime(2021, 8, 1, 0, 0, 0);

        int result = DateTime.Compare(EndDate, StartDate);

        Console.WriteLine("{0}", result);

        if(result < 0)

        {

            Console.WriteLine("Dates are invalid.");

        }

        else

        {

            Console.WriteLine("Dates are valid");

        }

        Console.WriteLine("----------------------");

        // Is Null Testing

        string valueStr = "1,2,3,4";

        if(!String.IsNullOrEmpty(valueStr))

        {

            if (valueStr.Contains(','))

            {

                foreach (string val in valueStr.ToString().Split(','))

                {   

                    Console.WriteLine("val = " + val);

                }

            }

        }

        Console.WriteLine("valueStr = " + valueStr);

        Console.WriteLine("----------------------");

        // Format Dates

        string displayValue = "Dec  8 2021  9:58AM";

        Console.WriteLine(displayValue);

        displayValue = DateTime.Parse(displayValue).ToString("MM-dd-yyyy");

        Console.WriteLine(displayValue);

        Console.WriteLine("----------------------");

        Console.WriteLine("");

        var encodeString = "Data%20Innovation";

        Console.WriteLine("Web UrlDecode: " + System.Web.HttpUtility.UrlDecode(encodeString));

        Console.WriteLine("Net UrlDecode: " + System.Net.WebUtility.UrlDecode(encodeString));

        Console.WriteLine("Web HtmlDecode: " + System.Web.HttpUtility.HtmlDecode(encodeString));

        Console.WriteLine("Net HtmlDecode: " + System.Net.WebUtility.HtmlDecode(encodeString));

        Console.WriteLine("----------------------");

        encodeString = "VMLY&R";

        Console.WriteLine("Web UrlDecode: " + System.Web.HttpUtility.UrlDecode(encodeString));

        Console.WriteLine("Net UrlDecode: " + System.Net.WebUtility.UrlDecode(encodeString));

        Console.WriteLine("Web HtmlDecode: " + System.Web.HttpUtility.HtmlDecode(encodeString));

        Console.WriteLine("Net HtmlDecode: " + System.Net.WebUtility.HtmlDecode(encodeString));

        Console.WriteLine("----------------------");

    }

}