}
public function knows()
{
echo "I {$this->name} know {$this->skill}" . PHP_EOL;
}
public function override()
{
parent::override();
echo "overridden!" . PHP_EOL;
}
}
$foo = new Person("foo", 20);
$bar = new Developer("bar", 30, "PHP");
$foo->introduce();
$bar->introduce();
$bar->knows();
$foo->override();
$foo->cannotOverride();
$bar->override();
$bar->cannotOverride();
// abstract class
abstract class ANinja
{
public abstract function kill(Person $someone);
protected abstract function isOk();
public function knowledge()
{
echo "this is a common method, already implemented!" . PHP_EOL;
}
}
class Ninja extends ANinja
