I'm working on a large codebase in an Eclipse project. Our codebase has both Python and C++ code. Since I only worked in Python until now, I created the project as a Python project. 
Now I'm about to work heavily with some of our C++ modules, and I would like the benefits of CTD. My Eclipse has CTD (the Eclipse C++ plugin) installed. How do I convert my existing PyDev project to work with C++?
Basically you could add C++ nature to the project. Eclipse project could have several natures simultaneously, so you will have both python and C++ goodies.

Right-click on the project.
Select: New -> Other
Under C/C++, select "Convert to a C/C++ project"
Converting a Python project to C++