我正在关注我在互联网上找到的一个简单的 OOP 教程。我快完成了，但我收到了我在主题中提到的错误。
这是输出：
Stefan's full name: Stefan Mischook
Notice: Use of undefined constant name - assumed 'name' in C:\xampp\htdocs\oop\class_lib.php on line 21
---> JOHNNY FINGERS
这里是index.php:
<?php
require_once('class_lib.php');
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>OOP in PHP</title>
</head>
<body>
<?php
$stefan = new person("Stefan Mischook");
echo "Stefan's full name: " . $stefan->get_name();
echo "<br>";
$james = new employee("Johnny Fingers");
echo "---> " . $james->get_name();
?>
</body>
</html>
这是 class_lib.php，包含类的文件：
<?php
// A variable inside a class is called a "property"
// Functions inside a class are called "methods"
class person
{
var $name; // If a property is declared with the "var" keywords it is considered public.
public $height;
protected $social_insurance;
private $pinn_number;
function __construct($persons_name)
{
$this->name = $persons_name;
}
protected function set_name($new_name)
{
if (name !="Jimmy Two Guns")
{
$this->name = strtoupper($new_name);
}
}
public function get_name()
{
return $this->name;
}
private function get_pinn_number()
{
return $this->$pinn_number;
}
}
class employee extends person
{
protected function set_name($new_name)
{
if ($new_name == "Stefan Lamp")
{
$this->name = $new_name;
}
else if ($new_name == "Johnny Fingers")
{
person::set_name($new_name);
}
}
function __construct($employee_name)
{
$this->set_name($employee_name);
}
}
// $this can be considered a special OO PHP keyword
// A class is NOT an object. The object gets created when you create an instance of the class.
// A handle is...
// To create an object out of a class you need to use the "new" keyword.
// When accessing methods and properties of a class you use the -> operator.
// A constructor is a built-in method that allows you to give your properties values when you create an object
// A private property can be accessed only by the same class.
// A protected property can be accessed by the same class and classes that are derived from that class.
// A public property has no access restrictions.
// Public, private and protected are called "acces modifiers" and it's all about control. It makes sense to control how people use classes.
// "extends" is the keyword that enables inheritance
// Child class methods can overwrite parent class methods simply by declaring a method with the same name again.
/* "::" allows you to specifically name the class where you want PHP to search for a method. If you want to access the method of the parent class instead of the overwritten one of the child class you can do it much simpler by calling it this way: parent::method() (you don't have to type the name of the class).*/
?>
不要介意评论，我将它们用于学习目的。非常感谢您，如果我需要在降级之前编辑我的问题，请告诉我。干杯!