CppDepend is non-intrusive. You don't have to modify your code to use it.
CppDepend is easy to tackle with. It won't take you more than 5 minutes to install it as a VisualStudio addin and analyze a C++ application with dozens of projects.
CppDepend is 100% integrated in Visual Studio 2015, 2013, 2012, 2010, 2008 and 2005. If you prefer you can use the standalone VisualCppDepend UI that collaborates with Visual Studio.