class BaseClass {
        function __construct() {
            print "In BaseClass constructor\n";
        }
    }

    class SubClass extends BaseClass {
        function __construct() {
            parent::__construct();
            print "In SubClass constructor\n";
        }
    }

    class OtherSubClass extends BaseClass {
        // inherits BaseClass's constructor
    }

    // In BaseClass constructor
    $obj = new BaseClass();
    $obj = new SubClass();
    $obj = new OtherSubClass();