public MortgageAccount(Customer customer, double balance, double interestRate) : base(customer, balance, interestRate) { }
public DepositAccount(Customer customer, double balance, double interestRate) : base(customer, balance, interestRate) { }
public Account(Customer customer, double balance, double interestRate) { this.customer = customer; this.balance = balance; this.interestRate = interestRate; }