class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Aktualny czas: {0}", DateTime.Now);
            new Alarm(10);

            Console.ReadKey();
        }
    }

    class Alarm
    {
        private DateTime _time;
        private Timer _alarm;

        public Alarm(int seconds)
        {
            _time = DateTime.Now.AddSeconds(seconds);

            _alarm = new Timer(1000);
            _alarm.Elapsed += new ElapsedEventHandler(checkAlarmTime);
            _alarm.Enabled = true;

            Console.WriteLine("Alarm został ustawiony na : {0}", this._time);
        }

        public int SetTime
        {
            set
            {
                this._time = DateTime.Now.AddSeconds(value);
            }
        }

        public DateTime GetTime
        {
            get
            {
                return this._time;
            }
        }

        private void checkAlarmTime(object sender, ElapsedEventArgs e) {
            if (e.SignalTime >= this._time)
            {
                Console.WriteLine("\n Alarm {0}", e.SignalTime);
                _alarm.Enabled = false;
            }
        }
    }