Php 未返回字符串

我试图访问父类以将信息从它传递给它的子类，然后将该信息回显到页面，但我似乎无法让

$flavor

从我创建的

Soda

类中回显出来。在屏幕上发出回声的是<代码>产品名称：太空果汁苏打口味：-显然我的

\u结构（我想）在
苏打
类中出了问题，但无法找出原因

class Product {

public $name = 'default_name';
public $price = 0;
public $desc = "default description";

function __construct($name, $price, $desc) {
    $this->name = $name;
    $this->price = $price;
    $this->desc = $desc;
}

public function getInfo() {
    return "Product Name: " . $this->name;
}
}

class Soda extends Product {

public $flavor;

function __construct($name, $price, $desc, $flavor) {
    parent::__construct($name, $price, $desc);
}

public function getInfo() {
    return "Product Name: " . $this->name . " Flavor: " . $this->flavor;
}
}

$shirt = new Product("Space Juice T-Shirt", 20, "Awesome Grey T-Shirt");
$soda = new Soda("Space Juice Soda", 2, "Thirst mutilator", "Grape");

echo $soda->getInfo();

您没有在Soda类中初始化
flavor

class Soda extends Product {

       public $flavor;

       function __construct($name, $price, $desc, $flavor) {
           parent::__construct($name, $price, $desc);
           $this->flavor = $flavor; // add this line here <<<<<<<<<<<<<
       }
       ...

类产品{
公众口味；
函数构造（$name、$price、$desc、$flavor）{
父项：：_构造（$name，$price，$desc）；
$this->flavor=$flavor；//在这里添加这一行在构造函数中分配
$flavor

function __construct($name, $price, $desc, $flavor) {
    parent::__construct($name, $price, $desc);
    $this->flavor = $flavor;
}