I'm a grader for a Computer Science class at my University and I would really like it if I can find some software to assist me in grading these assignments. They are done in C++.

Does anyone know of some good code analyzing software, especially if it pertains to this? What would be really nice is if there was something that could analyze code structure and see if there are any possibilities of cheating. I would always, of course, check with my own eyes to make sure, but at least it would help me to pin point those persons' sources that look similar.