Our first add-in function, NORMSDIST2(), was very simple to implement. Our next example is a little more complex. The inverse function, NORMSINV2(), can fail if the input is not between 0 and 1 (exclusive). In Excel, this failure is represented by the error type #NUM!.
Our next task is to use the XLL+ Function Wizard to generate a function that returns either a number or an error, depending on whether it is successful.
Make sure that Developer Studio is open and that Tutorial1 is the active project. Open or activate the file Tutorial1.cpp.
Use the New XLL+ Function item on the Tools menu to start the Function Wizard.
In the Add New Function dialog, fill in the name,
NORMSINV2, and click OK.
In the XLL+ Function Wizard, fill in the category and description of the function as follows:
Return type: CXlOper Category: Statistical Description: Returns the inverse of the standard normal cumulative distribution. The distribution has a mean of zero and a standard deviation of one.