class Person
{
     function calculateAge($dob)
     {
        echo "calculateAge called of Person Classn";
     }
}
?
class Customer extends Person
{
     function calculateAge($dob)
    {
       echo "calculateAge called of Customer Classn";
    }
}
?
$c1 = new Customer();
$p1 = new Person();
?
$c1->calculateAge("something");
$p1->calculateAge("something More");
?>