PHP面向对象-对象的比较（二）

class Person {
  public $name;
  public $age;

  public function __compare($person) {
    if ($this->age == $person->age) {
      return 0;
    } else if ($this->age < $person->age) {
      return -1;
    } else {
      return 1;
    }
  }
}

$person1 = new Person();
$person1->name = "Alice";
$person1->age = 30;

$person2 = new Person();
$person2->name = "Bob";
$person2->age = 40;

$result = $person1->__compare($person2);

if ($result == 0) {
  echo "Ages are equal";
} else if ($result < 0) {
  echo "Age of person 1 is smaller";
} else {
  echo "Age of person 1 is larger";
}