using System;
using System.Collections.Generic;
using System.Text;

namespace DelegateandObserver
{
    public delegate void HandleDelegate();
   public  class Observer
    {
        private IList<HandleDelegate> list = null;

        public Observer()
        {
            list = new List<HandleDelegate>();
        }

        public void AddObserver(HandleDelegate h)
        {
            list.Add(h);
        }

        public void RemoveObserver(HandleDelegate h)
        {
            if (list.Contains(h))
            {
                list.Remove(h);
            }

            return;
        }

        public void Do()
        {
            foreach (HandleDelegate h in list)
            {
                h();
            }
        }
    }
}