Math Functions: The Future Value of an Investment

 Introduction
 The FutureValue() function is used to calculate the future value of an investment. The syntax of this function is:
```Extended __fastcall FutureValue(Extended Rate,
int NPeriods,
Extended Payment,
Extended PresentValue,
TPaymentTime PaymentTime);```

Here is an example of calling this function:

```//---------------------------------------------------------------------------

#include <vcl.h>
#include <math.hpp>
#pragma hdrstop

#include "Exercise.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TfrmExercise *frmExercise;
//---------------------------------------------------------------------------
__fastcall TfrmExercise::TfrmExercise(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TfrmExercise::btnCalculateClick(TObject *Sender)
{
Extended Present, Future, Payment, Rate;
int Period;

Present = StrToFloat(edtPresentValue->Text);
Payment = StrToFloat(edtMonthlyPayment->Text);
Period = StrToInt(edtPeriods->Text);
Rate = StrToFloat(edtInterestRate->Text);
Future = labs(FutureValue(Rate / 100, Period, Payment,
Present, ptEndOfPeriod));

edtFutureValue->Text = FloatToStrF(Future, ffCurrency, 8, 2);
}
//---------------------------------------------------------------------------
void __fastcall TfrmExercise::btnCloseClick(TObject *Sender)
{
Close();
}
//---------------------------------------------------------------------------```