Before T2

Test2 is fastly approaching, but due to so much tests and assignments during last 2 weeks, I am not sure if remember everything for the test. If the proof of correctness of recursive program is not that hard(probably because we did one for A2), but the same proof for program with loops is not good for me. I still do not completely understand what is the loop invariant and how to prove that the loop terminates (here comes the book to help me, unfortunately). I have much time on Thursday, so I'll try to do my best.