Compare Function

I store e-mail addresses in a database that are to be used for notification purposes. When the clients add e-mail addresses I want to check and make sure they have not entered an e-mail addresss in twice. Here is what I've got:

I have two arrays that hold the email addresses from the database and the email addresses from the form. I want to loop through the form's array and check it against the database array. If it finds a match then add it to an error message. If it does not find a match add it to the database. Sounds simple.

Here is the function that does the comparison: Code: