深入理解PHP面向对象编程中的一对多关系

class Student {
  private $name;
  private $age;
  
  public function __construct($name, $age) {
    $this->name = $name;
    $this->age = $age;
  }
  
  public function getName() {
    return $this->name;
  }
  
  public function getAge() {
    return $this->age;
  }
}

class Class {
  private $name;
  private $students;
  
  public function __construct($name) {
    $this->name = $name;
    $this->students = array();
  }
  
  public function addStudent($student) {
    $this->students[] = $student;
  }
  
  public function getStudents() {
    return $this->students;
  }
}

class School {
  private $name;
  private $classes;
  
  public function __construct($name) {
    $this->name = $name;
    $this->classes = array();
  }
  
  public function addClass($class) {
    $this->classes[] = $class;
  }
  
  public function getClasses() {
    return $this->classes;
  }
}

// 创建学校对象
$school = new School("ABC School");

// 创建班级对象
$class1 = new Class("Class 1");
$class2 = new Class("Class 2");

// 创建学生对象
$student1 = new Student("Tom", 10);
$student2 = new Student("Jerry", 11);
$student3 = new Student("Alice", 12);
$student4 = new Student("Bob", 13);

// 添加学生到班级
$class1->addStudent($student1);
$class1->addStudent($student2);
$class2->addStudent($student3);
$class2->addStudent($student4);

// 添加班级到学校
$school->addClass($class1);
$school->addClass($class2);

// 输出学校的班级和学生
foreach ($school->getClasses() as $class) {
  echo "班级：" . $class->getName() . "
";
  foreach ($class->getStudents() as $student) {
    echo "学生：" . $student->getName() . "，年龄：" . $student->getAge() . "
";
  }
}