php - PHP子类不会覆盖新值

我对oop很陌生，我想弄清楚。我有以下哺乳动物类代码，我计划进一步发展。我有一个响应正确值的子类bear，但是我不能在grizzly子类中重写$name、$move、$ear或$sound值。

abstract class Mammal
{
    protected $name;
    protected $limbs;
    protected $offspring = 'live';
    protected $move;
    protected $eat;
    protected $sound;

    protected function __construct($name, $limbs, $offspring, $move, $eat, $sound) {
        $this->name = $name;
        $this->limbs = $limbs;
        $this->offspring = $offspring;
        $this->move = $move;
        $this->eat = $eat;
        $this->sound = $sound;
    }

    public function getOutput() {
        echo "The {$this->name} has four {$this->limbs}. The offspring is birthed {$this->offspring} and move by {$this->move}. They eat {$this->eat} and talk by {$this->sound}.";
    }
}

class Bear extends Mammal
{
    public function __construct() {
        Mammal::__construct('bear', 'claws', $this->offspring, '', '', '');
    }
}

class Grizzly extends Bear
{
    public function __construct() {
        Bear::__construct('grizzly bear', 'claws', $this->offspring, 'lumbering', 'salmon', 'roaring');
    }
}

$grizzly = new Grizzly;
$grizzly->getOutput();

我想得到的结果是：“灰熊有四个爪子。后代是活的，靠伐木业活动。他们吃三文鱼，咆哮着说：“我很感激你的帮助！

最佳答案

原因是bear类似乎不接受变量。
class Bear extends Mammal{ public function __construct() { //See, this constructor takes nothing Mammal::__construct('bear', 'claws', $this->offspring, '', '', ''); }}
我是这么做的
class Bear extends Mammal{ public function __construct($bear = 'bear') {//right hear Mammal::__construct($bear, 'claws', $this->offspring, '', '', ''); }}
Your code in codepad.org with my little change
注：我就是这样做的

关于php - PHP子类不会覆盖新值，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/19329247/