public void calculateQuota() { Contract.Installment = new List <Installment>(); for (int i = 1; i <= Months; i++) { double number = Contract.TotalValue / Months; double Interest = i * (_onlinePayment.interest(number)); number += Interest; double PaymentFee = _onlinePayment.paymentFee(number); number += PaymentFee; DateTime DueDate = Contract.Date.AddMonths(i); Installment Ins = new Installment(DueDate, number); Contract.Installment.Add(Ins); } }