Hello,
I am not sure if you are familiar with LabVIEW, but I am going to assume you are in order to simplify this answer. If you aren't familiar with LabVIEW, just let me know and I can go into more detail.
Within Vision Builder for Automated Inspection (VBAI) you can add a 'Calculator' step that will allow you to do minor computations and data manipulation involving measurements you have made. Unfortunately, if you are trying to create something more complex, pulling in an outside step is not currently supported in VBAI. Within the current version of VBAI you are limited to the preconfigured tools, however this will be changing soon. In the future (possibly soon), you will be able to use LabVIEW to develop steps that can be implemented in VBAI. This is going to be extremely cool!
As for C++, .NET, etc., I am not sure if VBAI will support steps made in these languages. Don't quote me on this, but it may be possible to pull in C++ code by creating a dll and using a call library function node in Labview. Whether or not this is going to be possible is yet to be determined.
Hope this helps,
Robert