Object Oriented PHP (Multi Level Inheritence)

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<h1 style="text-align: center;color: maroon;font-weight: bold; font-family: 'Mongolian Baiti'"> Object Oriented PHP (Multi Level Inheritence)</h1>
<br>
<?php


class Father
{

    public $a;
    public $b;

    public function getV($x, $y)
    {
        $this->a = $x;
        $this->b = $y;

    }
}

class Son extends Father
{
public $c=50;

 public $sum;
 public function add()
 {
     return $this->sum =$this->a +$this->b+ $this->c;

 }

}
class Gson extends Son
{
    public function display()
    {
        echo "Value Of A is : $this->a <br>";
        echo "Value Of B is : $this->b <br>";
        echo "Value Of C is : $this->c <br>";
        echo "Value Of Total Sum is :". $this->add()  ;


    }


}


 $obj =new Gson;
$obj->getV(30,20);
$obj->add();
$obj->display();


?>

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