Question 14-1.
Why should you use the .php extension for include files when other extensions such as .inc could be used instead?
Question 14-2.
What's a more secure function than md5() for encoding passwords before they're stored in the database?
Question 14-3.
Why shouldn't you use automatic global variables in your code?
Question 14-4.
What is considered to be untrustworthy user data?
See the Appendix for the answers to these questions.