​x
 
<!DOCTYPE html>
<html>
<body>
​
<?php
class MyClass {
  protected $number = 0;
}
​
class AnotherClass extends MyClass {
  public function add1() {
    $this->number++;
  }
​
  public function getNumber() {
    return $this->number;
  }
}
​
$obj = new AnotherClass();
$obj->add1();
echo "数字是 " . $obj->getNumber();
?>
​
</body>
</html>