如何为子方法添加更多功能？

Question

    class Parent_class{
    function parent_says(){
        echo "HI. I'm parent!";
    }
}

class Child_class extends Parent_class{
    function parent_says(){
        //I want it to also says "HI. I'm parent!", that's inside parent method.
        echo "I say hello!";
    }
}

$Child_class = new Child_class;
$Child_class->parent_says();

Answer 1

首先使用parent::调用父类的方法。 E.g。

class Child_class extends Parent_class{
    function parent_says(){
        parent::parent_says();
        echo "I say hello!";
    }
}

有关详细信息，请参阅here。