Exporting from .obj to .fbx source code I dont know if this is the right place to ask.. 

For a programming assignment in school I need to find in the source code where the export is made to an FBX file. Do you have any idea to where I should start to look? I've built everything with Cmake(it does not compile without 500 errors) and got a Blender project open in VS.
You can find the FBX importer and exporter code in the addons folder:

Blender_Installation_Folder\Your_Blender_Version\scripts\addons\io_scene_fbx

On my system it's here:
C:\Program Files\Blender Foundation\Blender\2.74\scripts\addons\io_scene_fbx

More about paths in blender in different operating systems

By the way, you don't need to compile from source to see this code's source, since this is a python script (you can just download and install an ordinary package for your operating system).