what would u do if your friend gets credited for your work?

It's like a scenario where you made a doodle on paper then threw it away. Now someone found it, published it and is now getting money for it. You admit the program was easy to write. It hardly took much time for you; is 30 minutes -really- that important to -you-?

If it is, however you shouldn't screw him over completely just ask for a mention in the bibliography or something.