继承:子类继承父类或者基类,比如魅族手机、小米手机、华为手机是子类,手机是基类。
class Phone {
public $price = 3699;//手机的起始价格
public function price(){
$this->price += 20;
return $this->price;
}
}
//魅族类price方法覆盖基类,并把价格降300
class Meizu {
public function price(){
$this->price = parent::price() - 300;//parent::方法名()调用基类price方法
return $this->price;
}
}
$phone = new Meizu();
$phone->price();//调用price方法
echo $phone->price;//取price值