static void Main(string[] args)
{
CDProjectStock stockValue = new CDProjectStock(284.8);
Caretaker caretaker = new Caretaker(stockValue);
caretaker.Undo();
caretaker.Save();
stockValue.SetSharePrice(276.98);
caretaker.Save();
stockValue.SetSharePrice(250.02);
caretaker.Save();
stockValue.SetSharePrice(299.47);
caretaker.Undo();
caretaker.Undo();
}
public Caretaker(CDProjectStock stockValue)
{
this.StockValue = stockValue;
}