1- Write a PHP program that tests whether an e-mail address is input correctly. Verify that the input begins with a series of characters, followed by the @ character, another series of characters, a period (.) and a final series of characters. Test your program, using both valid and invalid e-mail addresses.
2- Describe how cookies can be used to store information on a computer and how the information can be retrieved by a PHP program. Assume that cookies are not disabled on the client.