$this->doStuff();
// can call the protected function
return $this->status;
}
function __construct($c = 'blue')
{
$this->color = $c;
}
}
// create an instance of Car class
$myCar = new Car();
echo '<p>' . $myCar->color . '</p>';
echo '<p>' . $myCar->getStatus() . '</p>';
echo '<p>' . $myCar->doMoreStuff() . '</p>';
// works
echo '<p>' . $myCar->flag . '</p>';
// doesn't work
echo '<p>' . $myCar::$flag . '</p>';
// works
echo '<p>' . Car::$flag . '</p>';
// must reference the class::property
class SUV extends Car
{
public $has4WD = 'yes';
}
$newCar = new SUV('black');
echo '<p>' . $newCar->color . '</p>';
echo '<p>' . $newCar->getStatus() . '</p>';
echo '<p>' . $newCar->has4WD . '</p>';
echo '<p>' . $newCar->doMoreStuff() . '</p>';
// wouldn't work
static $doesHave4WD = true;
public function getStatus2()
{
return $this->status;
}
// static members are accessed directly from the class using ::
// they are not accessible from class instances
static function has4WD()
{
// can't use $this in a static method because it's not associated
// with an instance
//return $this->has4WD;
// we also can't access non-static members directly from the class
//return SUV::has4WD;
// note that the static variable has the $ in the name
return SUV::$doesHave4WD;
}
}
$yourCar = new Car(array('make' => 'Cadillac', 'model' => 'El Dorado', 'color' => 'pearl'));
$myCar = new SUV();
echo '<p>Your car color is ' . $yourCar->color . '</p>';
echo '<p>Your car ' . (isset($yourCar->has4WD) && $yourCar->has4WD ? 'has' : 'does not have') . ' four-wheel drive.</p>';
echo '<p>My car ' . (isset($myCar->has4WD) && $myCar->has4WD ? 'has' : 'does not have') . ' four-wheel drive.</p>';
echo '<p>Your car status is ' . $yourCar->getStatus() . '</p>';
echo '<p>My car status is ' . $myCar->getStatus() . '</p>';
// generates a warning because $status is private
echo '<p>My car status is ' . $myCar->getStatus2() . '</p>';
$myCar->has4WD();
// can't access static properties
echo SUV::has4WD();
// access the static member directly from the class
$this->color = $color;
}
}
class SUV extends Car
{
public $has4WD = false;
// child classes can override parent properties
public function getStatus()
{
// child classes can still access parent methods using parent::
return parent::getStatus();
}
}
$myCar = new Car('Mercedes', '760GL', 'black');
echo '<p>The color of my car is ' . $myCar->color . '.</p>';
$yourCar = new SUV('Hummer', 'H2', 'red');
echo '<p>The color of your car is ' . $yourCar->color . '.</p>';
echo '<p>My car status is ' . $myCar->getStatus() . '</p>';
$myCar->startEngine();
echo '<p>My car status is ' . $myCar->getStatus() . '</p>';
//$yourCar->startEngine();
echo '<p>Your car status is ' . $yourCar->getStatus() . '</p>';
echo '<p>Your car ' . (empty($yourCar->has4WD) ? 'does not' : 'does') . ' have 4WD.</p>';
echo '<p>My car ' . (empty($myCar->has4WD) ? 'does not' : 'does') . ' have 4WD.</p>';
echo '<p>Say something: ' . Car::saySomething() . '</p>';
// works but not recommended
echo $myCar::saySomething();
echo $myCar->saySomething();
?>
return $this->passKey;
}
public function getPassKey()
{
return 'foo';
}
}
// create an instance of the Car class
$myCar = new Car('Mercedes', '760EL', 'black');
output(Car::$instanceCount);
// public properties are externally accessible
//$myCar->color = 'red';
echo '<p>' . $myCar->color . '</p>';
//$myCar->status = 'on'; // generates an access fatal error_get_last
echo $myCar->startEngine();
// works
$yourCar = new SUV('Ford', 'Escalade', 'green');
echo '<p>' . $yourCar->model . '</p>';
echo '<p>' . $yourCar->has4WD . '</p>';
$f = 'startEngine';
output($yourCar->{$f}());
echo '<p>' . $yourCar->startEngine() . '</p>';
echo '<p>' . $myCar->getPassKey() . '</p>';
echo '<p>' . $yourCar->getPassKey() . '</p>';
echo '<p>' . $yourCar->getStatus() . '</p>';
echo '<p>' . $yourCar->getKey() . '</p>';
output(Car::$instanceCount);
unset($myCar);
// destroy object, calling destructor in the process
$c = 'Car';
output($c::$instanceCount);
