06.TextProcessingExercise-Valid Usernames

01.  Valid Usernames
Write a program that reads user names on a single line (joined by ", ") and prints all valid usernames.
A valid username is:
• Has length between 3 and 16 characters
• Contains only letters, numbers, hyphens and underscores
Examples
Input                                                         Output
sh, too_long_username, !lleg@l ch@rs, jeffbutt                jeffbutt

Jeff, john45, ab, cd, peter-ivanov, @smith                    Jeff
                                                              John45
                                                              peter-ivanov

using System;

namespace ExamResults
{
    class Program
    {
        static void Main(string[] args)
        {
              var userNames = Console.ReadLine().Split(", ");

            foreach (var userName in userNames)
            {
                if (userName.Length >= 3 && userName.Length <= 16)
                {
                    var counter = 0;
                    foreach (var symbol in userName)
                    {
                        if (!(Char.IsLetterOrDigit(symbol) || symbol == '-' ||  userName.Contains('_')))
                        {
                            break;
                        }
                        else
                        {
                            counter++;
                        }
                    }
                    if (counter == userName.Length)
                    {
                        Console.WriteLine(userName);
                    }
                }
            }
        }
    }
}