Exercise 6-4 Use the techniques you learned in this chapter to create a Guest Book script that stores visitor names and e-mail addresses in a text fi le. Include functionality that allows users to view the guest book and prevents the same user name from being entered twice. Also, include code that sorts the guest book by name and deletes duplicate entries.

This is from page 376 of PHP Programming with MySQL. The instructor had us read 335 – 364 so it has to do with multidimensional arrays. Exercise 6-4 Use the techniques you learned in this chapter to create a Guest Book script that stores visitor names and e-mail addresses in a text fi le. Include functionality that allows users to view the guest book and prevents the same user name from being entered twice. Also, include code that sorts the guest book by name and deletes duplicate entries. We were given exercise 6-1 as a guide to help us accomplish the task. Also attached.