A.18. Answer for Chapter 19
Were you able to solve the halting problem? We didn't really expect you to solve this problem since, in 1936, Alan Turing proved you couldn't create a general solution. You can read about the halting problem at Wikipedia: http://en.wikipedia.org/wiki/Halting_problem.
There's not much we can show you as an answer to an exercise about distributions. You know about testing now, so as long as your tests pass, you know you're doing the right thing (or the tests don't work!).
We're kicking you out into the real world now. We don't have anything left to tell you in this book. Go back and read the footnotes now. Good luck!