I have no problems giving you the code, I would just change one line and the prof would never be able to figure it out...

But, I thought your intention was to disallow the prof from thinking, 'hey, this is a great app, I'm gonna go sell it to some supermarket', and having him/her sell it without your consent or against your will. In the real world, that's illegal. But no matter security features you encode into the app, if part of the assignment is to hand over the source code (which I assume since he/she would be grading it), then you've basically given the jesture the keys to the kingdom....

But if you don't have to give the source code (or all of it), then I'll be more than glad to help you with it...