public string UnAllocateClassRoom()
 {
     if (aClassRoomGateway.IsRoomUnallocated())
     {
         return("Room Already unallocated");
     }
     else
     {
         int rowAffected = aClassRoomGateway.UnAllocateClassRoom();
         if (rowAffected > 0)
         {
             return("Room unallocated");
         }
         else
         {
             return("Room unallocation falied");
         }
     }
 }