Finance Functions: The Present Value of an Investment

The PresentValue() function calculates the total amount that future investments are worth currently. Its syntax is: Extended __fastcall PresentValue(constExtended Rate, int NPeriods, const Extended Payment, const Extended FutureValue, TPaymentTime PaymentTime); Here is an example:

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void __fastcall TForm1::btnCalculateClick(TObject *Sender)
{
	Extended Present, Future, TheRate, Payments;
	int NPeriod;

	Future = StrToFloat(edtFuture->Text);
	Payments = StrToFloat(edtPayments->Text);
	TheRate = StrToFloat(edtRate->Text) / 12;
	NPeriod = StrToInt(edtNPeriods->Text);

	double Rate = TheRate / 100;
	// Apply the function
	Present = PresentValue(Rate, NPeriod,
	-Payments, -Future, ptStartOfPeriod);
	// Display the payment
	edtPresent->Text = FloatToStrF(Present, ffCurrency, 8, 2);
}
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