HW4 grading.

5 points total.

0 points if no hw4.c file in your ~/handin/ directory.  That includes
if you didn't spell it correctly, etc.

-1 if no hw4 file in your ~/handin/ directory.  That should have been 
there from when you compiled hw4.c

1 points for the extra printf messages.  -1 if not there at all.  minus
something if not done right.