This program is the final project of a course I take.  Some of the code is 
written by the instructor ric2k1, while other written by robertabcd.

The whole project uses "copyleft" license, so you can take any code if you 
want, and of course there is NO WARRANTY.  Also, it is NOT guaranteed that
the program runs correctly without any flaws.

I will NOT take any responsibilities to your grades if you use my code.

Please email me if you've found a bug, I will fix it if I have time.