using System;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        // print "a, bb, ccc"

        Console.WriteLine(Collate("a", "bb", "", "ccc"));

    }

​

    private static string Collate(params string[] args)

    {

        var retString = string.Empty;

​

        foreach (string arg in args)

        {

            if (!string.IsNullOrWhiteSpace(arg))

            {

                if (retString == string.Empty)

                    retString = arg;

                else

                    retString = retString + ", " + arg;

            }

        }

        return retString;

    }

}

​

​