Programmatically parse and edit C++ Source Files
This is similar to AST from C code
If your comfortable with Java antlr can easily parser your code into an abstract syntax tree, and then apply transformation to that tree. A default AST transform is to simply print out the original source.
You can use any parser generator tool to generate a c++ parser for you, but first you have to get the CFG (context free grammar) for C++ , check Antlr
Edit:
Also Antlr supports a lot of target languages
You need a working grammar and parser for C++ which is, however, not too easy as this can't be constructed with most parser generators out there. But once you have a parser you can actually take the abstract syntax tree of the program and alter it in nearly any way you want.