BinhHelper.cs

using System;

namespace BinhHelper
{
    public class LogHelper
    {
        public void myLog(string str)
        {
            string timestamp = DateTime.Now.ToString("dd/MM/yyyy hh:mm:ss");
            Console.WriteLine("[" + timestamp + "]" + " " + str);
        }
    }

    public class DateTimeHelper
    {
        public string myDateTimeString(string str)
        {
            return DateTime.Now.ToString(str);         
        }
    }
}