include和require的区别/实例演示：类与对象关键字 魔术方法

include和require的区别

// include
// 相对路径
include 'inc/hello.php';
// 绝对路径
include __DIR__ . '/inc/hello.php';
echo $username;
// require
// 当路径不存在,代码出错后直接退出
require __DIR__ . 'inc/hello1.php';
echo $username;

类与对象关键字 魔术方法

class Stu{
public $username;
private $age = 18;
static $tel;
    public function __construct($username, $age, $tel)
    {
        $this ->username = $username;
        $this ->age = $age;
        $this ->tel = $tel;
    }
    public function __get($age)
    {
        if($age === 'age'){
        return $this ->$age + 5;
        }
    }
    public function __set($age, $value)
    {
        if($age === 'age'){
            if($value >=18 && $value <=30){
            $this ->$age =$value;
            }   else{
                echo '你超龄了';
            }
    }
    }
}
$user = new Stu('小李', 19, 13632801080);
echo $user ->age, '<br>';
$user->age = 48;