A little OO Q. How do I "extend" classes

[Anon]

Ive run into a little dilemma of mine here.
I am relativelt new to OO programming, but Ive managed to haul out a class of my own.

Now. All I wanna do is to use one or two of the "methods" in the class i`ve already made, in a new class.

I`ve been using a book for a guided tour into the world of classes, the book explained in detail all I neede to know about OO programming...

The book also started sizzling with a command: "extend class whatever"
This, as I understood it, meant that one could use the "methods" or functions within that motherclass to produce an entirely different output with the new class.

And that is exactly what I want to do.
But. How?
Do I "require" the first class in the new class?

will I have to define the var`s again?

Can some of you brilliant experts help me please?

-trond-

[Anon]

class newClass extends originalClass
{
var $class_var // if the original class had $class_var this variable will overide it... methods work in the same way
}

Hope you understand this

Andreas

[Anon]

But if I want to initate the extended class to produce the desired output... How do I do that??

Do I require both classes where I want the page to be created and just call the "new newclass()"

Or does an extension has to be written in the same file as the "mother" class??

[Anon]

Hi,

have you tried anything yet ??
Anyway, you have your base class

class a_bit_functionality
{
function do_something()
{...}
}

You want to have the function "do_something()" in a different class.

class some_more_functionality extends a_bit_functionality
{
function do_something_else()
{...}
}

in a_bit_functionality you can use the function do_something, in some_more_functionality you can use the function do_something AND the function do_something_else ...

If you want to put both classes into one file you can do so, but I personally don't like it having two classes into one file, so I would have a file class.a_bit_functionality.php4 and a file class.some_more_functionality.php4. But if you want to extend a class PHP needs to know the class. So in your class.some_more_functionality.php4 you would start with an include or require.
include("./class.a_bit_functionality.php4");

class some_more_functionality extends a_bit_functionality
{...}

hope that helps.

cya Rob

[Anon]

Excellent explanation, Rob. I just have one suggestion. Instead of

include("./class.a_bit_functionality.php4");

use

include_once("./class.a_bit_functionality.php4");

That way you can use both the base and extended classes on the same page without having to worry about multiple includes.

• Beth

[Anon]

Thank you all for your replies!
Now I get it!
classes are great! 🙂