Position the cursor in the edit window on the line after the TODO comment and add the following code:
double v = pow((1 + Rate), nPeriods);
*FV = -(
(PresentValue * v) +
(Payment * (1 + (Rate * PaymentType))) * ((v - 1) / Rate)
Since you refer to the pow function, you have to add the following preprocessor statement after all other include statements at the beginning of the file:
The final step is to build the DLL. When you build it, you register the COM procedure with the Windows registry.