[SOLVED] classes and objects

[Cardale]

I was reading over some documentation about classes and had a question.  When you put a object into a certain state it stays that way?  So the value of that state could be used again in another instance?  Like another script after the state has been set?

[Ken2k7]

Yeah, you can do that with static and possibly final. That is assuming you are using PHP 5.

[Cardale]

So say for instance I had a function like this

 

<?php
function test()
{
    static $a = 0;
    echo $a;
    $a++;
}
?>

 

I could call this function in one page and it would set its value to 1 and then have a link to the next page which calls the function and it would display 2?

[Ken2k7]

No, you said classes and objects, not functions.

[Cardale]

ok so if I put that into a class then it would work?

[Ken2k7]

Try this -  (I haven't tested it)

<?php

class A {
     private static $e = 0;
     public function __construct ($e = null) {
          if (!is_null($e)) A::$e = $e;
     }
     public function getE () { return A::$e; }
}

$e = new A(5);
$f = new A;

echo $f->getE();

[Cardale]

I tested the function out using three separate pages.  One for the class then another to set the value of e to 5 then the third file to get the value of e and it was still 0..I included the class in test2 and test3 pages.

 

Is this not what you meant?

[Philip]

You need to use sessions or a database/flat file to continue using a value across multiple scripts.

 

Static reads as following:

Declaring class members or methods as static makes them accessible without needing an instantiation of the class. A member declared as static can not be accessed with an instantiated class object (though a static method can).

[Cardale]

I guess I need to just give up.  I have been trying to figure out a way to catch a error and have it sent to another page without POST or GET methods.  I save the error in a flat file didn't want to read that and wanted to avoid using a database, but I guess whats the difference in this instance.  It would make things a lot simpler.

 

should I use sessions for something like this?

[Ken2k7]

There is the try...catch.

 

<?php

try {
     echo 5/0;
} catch (Exception $e) {
     header('Location: www.google.com');
}

[Cardale]

I wanted to pass the error to a different page so it wouldn't look so horrible and have a half cut off page.  try and catch works with errors and exceptions?  I thought they were different.??

[Ken2k7]

You are absolutely right!

 

Use set_error_handler

[Cardale]

Right right...