Finance Functions: The Number of Periods of an Investment

The NumberOfPeriods() function calculates the number of periodic payments of an investment. Its syntax is: Extended __fastcall PeriodPayment(constExtended Rate, int Period, int NPeriods, const Extended PresentValue, const Extended FutureValue, TPaymentTime PaymentTime); Here is an example:

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void __fastcall TForm1::btnCalculateClick(TObject *Sender)
{
	Extended Present, Future, TheRate, Payments, NPeriod;
	
	Present = StrToFloat(edtLoan->Text);
	Future = StrToFloat(edtFuture->Text);
	Payments = StrToFloat(edtPayments->Text);
	TheRate = StrToFloat(edtRate->Text) / 12;
	
	double Rate = TheRate / 100;
	// Apply the function
	NPeriod = NumberOfPeriods(Rate, -Payments, -Present,
	Future, ptStartOfPeriod);
	// Since the number of periods is really an integer, find its ceiling
	Extended Actual = Ceil(NPeriod);
	// Display the number of periods
	edtNPeriods->Text = FloatToStr(Actual);
}
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void __fastcall TForm1::btnExitClick(TObject *Sender)
{
	PostQuitMessage(0);
}
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