PHP面向对象：不使用构造函数初始化父类私有属性的策略

<?php
class Fruit {
  private $name;
  private $color;
  // 缺少构造函数

  public function intro() {
    echo "The fruit is {$this->name} and the color is {$this->color}.";
  }
}

class Strawberry extends Fruit {
  public function message() {
    // 假设这里需要显示父类的介绍
    echo $this->intro();
  }
}

// 尝试直接实例化并传入参数，这会导致错误，因为Fruit和Strawberry都没有定义接收这些参数的构造函数
// $strawberry = new Strawberry("Strawberry", "red"); 
// $strawberry->message();
?>

<?php
class Fruit {
  private $name;
  private $color;

  /**
   * 公共方法，用于设置水果的名称和颜色
   * @param string $name 水果名称
   * @param string $color 水果颜色
   */
  public function describe(string $name, string $color): void {
    $this->name = $name;
    $this->color = $color;
  }

  /**
   * 公共方法，用于介绍水果
   */
  public function intro(): void {
    echo "The fruit is {$this->name} and the color is {$this->color}.";
  }
}

// Strawberry 继承自 Fruit
class Strawberry extends Fruit {
  /**
   * 子类方法，用于显示水果信息
   */
  public function message(): void {
    // 调用父类的intro方法来显示信息
    $this->intro();
  }
}

// 实例化 Strawberry 对象
$strawberry = new Strawberry();

// 使用父类的公共方法设置属性
$strawberry->describe("Strawberry", "red");

// 调用子类的方法来显示信息
$strawberry->message(); // 输出: The fruit is Strawberry and the color is red.
?>

<?php
class Fruit {
  private $name;
  private $color;

  public function describe(string $name, string $color): void {
    $this->name = $name;
    $this->color = $color;
  }

  public function intro(): void {
    echo "The fruit is {$this->name} and the color is {$this->color}.";
  }
}

class Strawberry extends Fruit {
  // 在此示例中，如果message方法仅调用intro，则可以省略
  // public function message(): void {
  //   $this->intro();
  // }
}

$strawberry = new Strawberry();
$strawberry->describe("Strawberry", "red");

// 直接调用父类的公共方法
$strawberry->intro(); // 输出: The fruit is Strawberry and the color is red.
?>