public bool AddCard(string cardnumber) { if (IsValidCardnumber(cardnumber)) { Cardnumbers.Add(cardnumber); return(true); } return(false); }
public Customer(string name, bool temporary, decimal balance, string cardnumber) : this(name, temporary, balance) { if (!IsValidCardnumber(cardnumber)) { throw new ArgumentException("cardnumber"); } Cardnumbers.Add(cardnumber); }