protected internal BaseCard(double turnover, CardHolder cardHolder) { Turnover = turnover; }
public GoldCard(double turnover, CardHolder cardHolder) : base(turnover, cardHolder) { CardHolder = cardHolder == null ? throw new NullReferenceException() : cardHolder; }
protected CardHolder(CardHolder cardHolder) { FirstName = cardHolder.FirstName; LastName = cardHolder.LastName; }