public void Unregister(Model_StockMarketDisplay observer)
{
// remove the observer from list of observers
this.listOfObservers.Remove(observer);
}
// the register method allows for an observer to register to the realTimeData so that they can implement the observer pattern and update accordingly
public void Register(Model_StockMarketDisplay observer)
{
// add the observer to the list of observers
this.listOfObservers.Add(observer);
observer.Update(this); // call update to ensure everything is up to date
}