} public function __get($object) { return $this->{$object}; } public function cost() { return $this->_strategy->cost($this); } public function type() { return $this->_strategy->type($this); } } class Arts extends Lesson { protected $discount = 0.75; protected $type = "文科"; } class Science extends Lesson { protected $discount = 0.5; protected $type = "理科"; } //应用 $arts = new Arts(6, new Math()); echo $arts->type() . $arts->cost(); echo "<br>"; $science = new Science(6, new Math()); echo $science->type() . $science->cost();