Is there a tool that can parse C++ files within a project and generate UML from it?
Here are a few options:
Step-by-Step Guide to Reverse Engineering Code into UML Diagrams with Microsoft Visio 2000 - http://msdn.microsoft.com/en-us/library/aa140255(office.10).aspx
BoUML - http://bouml.free.fr/features.html
StarUML - http://staruml.sourceforge.net/en/
Reverse engineering of the UML class diagram from C++ code in presence of weakly typed containers (2001) - http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.27.9064
Umbrello UML Modeller - http://uml.sourceforge.net/
A list of other tools to look at - http://plg.uwaterloo.ca/~migod/uml.html
StarUML does just that and it is free. Unfortunately it hasn't been updated for a while. There were a couple of offshoot projects (as the project admins wouldn't allow it to be taken over) but they too have died a death.
UML Studio does this quite well in my experience, and will run in "freeware mode" for small projects.