re-added BaseSubject

BaseSubject.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Eryan
+{
+    public class BaseSubject : Subject
+    {
+        List<Observer> observers = new List<Observer>();
+        Event e;
+
+        public void registerObserver(Observer o)
+        {
+            foreach (Observer observer in observers)
+            {
+                if (observer.Equals(o))
+                    return;
+            }
+            observers.Add(o);
+        }
+
+        public void removeObserver(Observer o)
+        {
+            observers.Remove(o);
+        }
+
+        public void notifyObservers()
+        {
+            foreach (Observer observer in observers)
+            {
+                observer.update(e);
+            }
+        }
+    }
+}