[RESOLVED] OO newbie issue !

[quecoder]

Hey there , when instantiating an inherited from A , Class B which uses a __construct() ,,, that I want it to show the echo in the parent class with a different sentence by overriding the value of $atr1 .. why it gives me an error :

Parse error: syntax error, unexpected '}' in F:\localhost\htdocs\php\prev0~.php on line 30

class A
   {
     protected $atr1 = "a value ";
     protected function kh ()
       {
         echo " The \$atr value is = this->$atr ";
       }

}

class B extends A
      {
       function __construct()
       {
      $this -> $atr1 = "diffenernt value ";
      kh()
      }
      }

$x = new B();

Another question : Do you suggest for a beginner in PHP to start studying OO ?

[quecoder]

var $atr1 = "different";
parent::kh();

Doesn't work as well ,,,
And why using parent:: ,, I didnt override the function .. I imagin inherited classes as using include ( ofcourse with more advanced options) ... correct me if i'm wrong..

[quecoder]

I think its now working :

class A
   {
     protected $atr1 = "a value ";
     protected function kh ()
       {
         echo " The \$atr value is = $this->atr1 ";
       }

}

class B extends A
      {

  var $atr1 = "different";
  function __construct() {
  parent::kh();
                          }
  }

$x = new B(); 

Though I don't understand why !

[NogDog]

Yes, learing OOP at the beginning will be a good way to learn good software design practices and avoid learning bad coding habits. However, be aware that simply learning how to use classes, objects, and their associated PHP functions does not mean you are doing object-oriented programming: it is entirely possible to write a procedural script using classes, and it is possible (though more difficult) to do object-oriented programming without classes.

The reason your last example worked is that the child class B overwrites the $atr1 parameter with a different default value. Thus when you call the parent's kh() method, you are now using the new value. Also, since you are inheriting methods as well as data, you do not need to call the method via "parent::":

<?php
class A
{
   protected $atr1 = "a value ";
   protected function kh ()
   {
      echo " The \$atr value is = $this->atr1 ";
   }
}

class B extends A
{
   protected $atr1 = "different";
   function __construct()
   {
      $this->kh();
   }
}

$x = new B();

[johanafm]

NogDog wrote:

Also, since you are inheriting methods as well as data, you do not need to call the method via "parent::":

unless you override the parent method definition of kh() and specifically want to access the base definition of it.

class A
{
   protected $atr1 = "a value ";
   protected function kh ()
   {
      echo " The \$atr value is = $this->atr1 ";
   }
}

class B extends A
{
   protected $atr1 = "different";
   protected function kh() {
		echo "This function is $this->atr1 <br>";
   }
   function __construct()
   {
      $this->kh();
      parent::kh();
   }
}

$x = new B();

[quecoder]

NogDog , another awesome post from you !!! 10/10
Johanafm , a GREAT piece of info 🙂 .