If i have 2 classes how do take a variable from one while inside another class. This is what i had but it doesn't work:

example:

file: example1.php

PHP Code:

class class1
{
var variable;
}
$class1 = &New class1;
$class1->variable = "Hello World"; 


file: example2.php

PHP Code:

include ("example1.php")

class class2
{
    function get_variable()
    {
    $variable = $class1->variable;
    return ($variable);
    }
}
$class2 = &New class2;
$variable = $class2->get_variable();
echo $variable; 


Example 1:

PHP Code:

<?php

class class1
{
  var $variable  = "Hello World";  
}

class class2
{
    var $_obj;
    
    function class2($obj){
        $this->_obj=$obj;
    }
    
    function get_variable()
    {  
          return ($this->_obj->variable;);
    }
}
$class1 = new class1();
$class2 = new class2($class1);
$variable = $class2->get_variable();
echo $variable;  
?>

Example 2:

PHP Code:

<?php

class class1
{
  var $variable  = "Hello World";  
}

class class2
{
    function get_variable()
    {  
       $class1 = new class1();
       $variable = $class1->variable;
       
       return ($variable);
    }
}



$class2 = new class2();
$variable = $class2->get_variable();
echo $variable;  

?>

You were almost with it but you failed to either create a new class 1 obj within class 2 or pass class1 when creating class2.

This is called Aggregation and is when one class has access to another, the second class perhaps having been instantiated outside the first. If the first object “dies”, the second will continue to “live”. This is commonly seen with data access objects, which may be passed to many other objects, which themselves may “die” leaving the data access object to continue.

Ibbo

Thank you for your help

I am now having a few problems with classes and mysql queries.

This is an example of the kind of thing i am doing, but it doesn't work:

PHP Code:

<?php
class class1
{
  var $variable  = "1";  
}

class class2
{
    var $_obj;
    
    function class2($obj){
        $this->_obj=$obj;
    }
    
    functionquery()
    {  
        $select_array = mysql_query("SELECT * FROM `table` WHERE `message_id` <= '$this->_obj->variable'") or die(mysql_error());
        while ($get_array = mysql_fetch_array($select_array))
        {
        echo $get_array['message']."<br>";
        }
    }
}
$class1 = new class1();
$class2 = new class2($class1);
$variable = $class2->query();
?>

To get it to work i have to:

PHP Code:

<?php
class class1
{
  var $variable  = "1";  
}

class class2
{
    var $_obj;
    
    function class2($obj){
        $this->_obj=$obj;
    }
    
    functionquery()
    {  
        $variable = $this->_obj->variable;
        $select_array = mysql_query("SELECT * FROM `table` WHERE `message_id` <= '$variable'") or die(mysql_error());
        while ($get_array = mysql_fetch_array($select_array))
        {
        echo $get_array['message']."<br>";
        }
    }
}
$class1 = new class1();
$class2 = new class2($class1);
$variable = $class2->query();
?>

Why is that?

Try passing it like '{$this->_obj->variable}'

Failing that I dont know why its failing in method 1. However there is nothing wrong with option 2 method either (which is good practice too as working directly on vars from another class may cause mayhem if others are using those vars too).

It gets a bit complex but basically copy remote var into a local one. Work on the local one then write it back should you need to.

I know this example of yours does not need that sort of thing to happen but if you start to practice it now you will be better off when dealing with bigger apps.

Ibbo

Thanks again Works.