classes?

[falsepride]

whats the purpose of a class in php? what is a class? can explain classes to me in a easy to understand way? what does -> do in a class?

[falsepride]

okay i think im starting to grasp this. a class is something to control certian variables. like in html when you create a style using .name {background-color:#000000;} any thing you give that class will act in the same way.

[idx]

Sortof.

Your class is a container for functions and variables. Makes it easy to share code and compartmentalize functions related to a common task.

-> in a class points to a variable or function..

And as luck would have it, there is a codenewbie article on OO PHP.

Note: The article seems to go with php4. PHP5 introduces a slew of new stuff.

-r

[falsepride]

im asuming variables within a class or only local, right? i understand classes now, i dont think ill ever use them though.

[idx]

They are only available within a class. So you'd have to reference the instance of the object you created.

eg:

PHP Code:

$article = new Article(4);
echo $article->text; 


Classes are very powerful if you use them correctly, so I wouldn't ignore them alltogether. Although depending on what types of programs you're developing, you may not [yet] see the need.

-r

[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.