贷款摊销代码计算

我有一个贷款摊销代码，我在网上找到并做了一些修改，以满足我的需求（C＃）。 我遇到的问题是计算包含在循环中的月利息。 它不会返回正确的值。

下面是我的代码（有点长）：

private void CalculateLoan() { // Make sure we use types that hold decimal places DateTime payDate = DateTime.ParseExact(_startDate.Value, "yyyyMMdd", null); double interestRate = 0; double monthlyInterest = 0; double loanAmount; short amortizationTerm = 0; double currentBalance; double cummulativeInterest = 0; double monthlyPrincipal = 0; double cummulativePrincipal = 0; loanAmount = double.Parse(_principal.Value); currentBalance = loanAmount; interestRate = double.Parse(_interestRate.Value) * 0.01; amortizationTerm = short.Parse(_period.Value); // Calculate the monthly payment and round it to 2 decimal places var monthlyPayment = ((interestRate / 12) / (1 - (Math.Pow((1 + (interestRate / 12)), -(amortizationTerm))))) * loanAmount; monthlyPayment = Math.Round(monthlyPayment, 2); // Storage List List amortPaymentList = new List(); // Loop for amortization term (number of monthly payments) for (int j = 0; j < amortizationTerm; j++) { // Calculate monthly cycle monthlyInterest = currentBalance * interestRate; **<-----problem here** monthlyPrincipal = monthlyPayment - monthlyInterest; currentBalance = currentBalance - monthlyPrincipal; if (j == amortizationTerm - 1 && currentBalance != monthlyPayment) { // Adjust the last payment to make sure the final balance is 0 monthlyPayment += currentBalance; currentBalance = 0; } // Reset Date payDate = payDate.AddMonths(1); // Add to cummulative totals cummulativeInterest += monthlyInterest; cummulativePrincipal += monthlyPrincipal; amortPaymentList.Add (new AmortPayment { RowNumber = j + 1, Date = payDate, ScheduledPayment = Math.Round(monthlyPayment, 2), Interest = Math.Round(monthlyInterest, 2), TotalRepayment = Math.Round(monthlyPayment + monthlyInterest, 2), Balance = Math.Round(currentBalance, 2), TotalInterest = Math.Round(cummulativeInterest, 2), TotalBalance = Math.Round(currentBalance + cummulativeInterest, 2) }); // Add values to SAP matrix _rowNo.Value = (j + 1).ToString(); _date.ValueEx = payDate.ToString("yyyyMMdd"); _payment.Value = monthlyPayment.ToString(); _interest.Value = monthlyInterest.ToString(); _totalRepayment.Value = (monthlyPayment + monthlyInterest).ToString(); _balancePrincipal.Value = currentBalance.ToString(); _balanceInterest.Value = cummulativeInterest.ToString(); _total.Value = (currentBalance + cummulativeInterest).ToString(); _form.Freeze(true); oMatrix.AddRow(); _form.Update(); _form.Freeze(false); } } 

有人可以告诉我，我的错误发生在monthlyInterest = currentBalance * interestRate; ？ 任何帮助赞赏。

Answer 1

你应该使用一个较高的利率而不是每年，只需将利率设为12

 monthlyInterest = currentBalance * interestRate / 12;