PHP Interview Questions
How send email using php?
To send email using PHP, you use the mail() function. This mail() function accepts 5 parameters as follows (the last 2 are optional). 

<?php 
    mail($to,$subject,$message,$headers); 
?>

mcrypt_encrypt : string mcrypt_encrypt ( string $cipher , string $key , string $data , string $mode [, string $iv ] ); 
Encrypts plaintext with given parameters

finally you can't send email from localhost.