[sde]

another cool thing about classes is that PHP supports inheritence too, which means you can use existing classes to add to your own with the keyword extends.

PHP Code:

<?
class person{
  var $first_name;
  var $last_name;
  
  // constructor
  function person($first_name,$last_name){
    $this->first_name = $first_name;
    $this->last_name = $last_name;
  }
}

class user extends person{
  var $username;
  var $password;
  
  // the person constructor does not execute unless you
  // call it in this extended class. $this->person()
  // we could call it in the user constructor, but i'm
  // just creating its own.
  
  function user($first_name,$last_name,$username,$password){
    $this->first_name = $first_name;
    $this->last_name = $last_name;
    $this->user_name = $username;
    $this->password = $password;
  }
}

// now when i create a new user, it has all the functions
// that the person class has along with new ones we create.
$myobject = new user("john","smith","jsmith","xx123xx");

echo "Welcome ". $myobject->first_name ." ". $myobject->last_name .";
?>

there is no example here that is too complicated to easily imagine doing it without classes, but it is a powerful tool when you need it.