Hi I have a question regarding $this.
class foo {
function __construct(){
$this->foo = 'bar';
}
}
class bar extends foo {
function __construct() {
$this->bar = $this->foo;
}
}
would
$ob = new foo();
$ob = new bar();
echo $ob->bar;
result in bar??
I only ask due to I thought it would but apart of my script does not seem to result in what i thought.
To quote the PHP manual:
Note: Parent constructors are not called implicitly if the child class defines a constructor. In order to run a parent constructor, a call to parent::__construct() within the child constructor is required.
This means that in your example when the constructor of bar runs, it doesn't run the constructor of foo, so $this->foo is still undefined.
PHP is a little odd in that a parent constructor is not automatically called if you define a child constructor - you must call it yourself. Thus, to get the behaviour you intend, do this
class bar extends foo {
function __construct() {
parent::__construct();
$this->bar = $this->foo;
}
}
You don't create an instance of both foo and bar. Create a single instance of bar.
$ob = new bar();
echo $ob->bar;
and as other answers have pointed out, call parent::__construct() within your bar constructor
