OO programming problem

[jordy]

I have a problem with OO programming in php5. Im fairly new in OO programming in php. I have a class (DJCms) that makes a new class (bar). The bar class cannot access any variables in DJCms. I want to manipulate the DJCms::$foo var from the bar class. Is this possible in a way?

class DJCms {
  var $foo;

  function __construct() {
	$this->foo = "foo";
    $obj = new bar();
	echo $this->foo;
  }

  function setFoo($var) {
	$this->$foo = $var;
  }
}

class bar {

  function __construct() {
	// some string to set the parents $foo to bar
	DJCms::setFoo("bar");
  }

}

[Weedpacket]

The answer is mainly that you need to say that DJCms is the parent of bar. Doing that is the responsibility of bar (a class can have only one parent, but any number of children).

class DJCms
{
	var $foo;

function __construct()
{
	$this->foo = "foo";
	echo $this->foo;
}

function setFoo($var)
{
	$this->foo = $var;
}
}

class bar extends DJCms
{

function __construct()
{
	parent::setFoo("bar");
}

}

$t = new bar;
echo $t->foo;

Since the bar class inherits the properties and methods of the DJCms class, the latter could be simplified to

class bar extends DJCms
{

function __construct()
{
	$this->foo='bar';
}

}

[jordy]

I changed the code a bit to my problem. I want bar to actually change the $foo var in DJCms. So the code that prints foobarfoo should print foobarbar.

Anyone?

    class DJCms 
{ 
    var $foo; 

function __construct() { 
    $this->foo = "foo"; 
    echo $this->foo; 
	$t = new bar; 
	echo $t->foo;
    echo $this->foo;  
} 

function setFoo($var) { 
    $this->foo = $var; 
} 
} 

class bar extends DJCms { 

function __construct() 
{ 
    parent::setFoo("bar"); 
} 

} 

$obj = new DJCms();
// prints foobarfoo

[Shrike]

You getting confused between inheritance and aggregation. In your example, you create an instance of DJCms, and then in the constructor you create an instance of bar (which inherits from the class DJCms, but it's not part of the same instance you created earlier. Weedpacket has already shown you how it should be done

class a 
{ 
  protected $foo; // Make this protected so child classes can access it 
  function __construct() 
  { 
    $this->foo = "foo"; 
  } 

  function getFoo()
  {
    return $this->foo;
  }
} 

class b extends a 
{ 
  function __construct() 
  { 
    parent::__construct(); 
  } 

  function setFoo($var) 
  { 
    $this->foo = $var; 
  } 
} 


$b = new b; 
echo $b->getFoo(); 
$b->setFoo("bar"); 
echo $b->getFoo();

Note: I added a getFoo() method since the $foo property is now protected. As a rule properties shouldn't be accessible outside of a class, but it's up to you if you allow it.