Tìm hiểu set và get trong PHP OOP (ok)

https://freetuts.net/tim-hieu-set-va-get-trong-php-oop-276.html

C:\xampp\htdocs\php\demo.php

<?php
class ClassName {
  private $__username;
  private $__password;
  function setUsername($value) {
    $this->__username = $value;
  }
  function setPassword($value) {
    $this->__password = $value;
  }
  function getUsername() {
    return $this->__username;
  }
  function getPassword() {
    return $this->__password;
  }
}
$class = new ClassName();
$class->setUsername('Lionel Phạm');
$class->setPassword('12345678');
echo $class->getUsername();
echo $class->getPassword();

C:\xampp\htdocs\php\demo.php

<?php
class ClassName {
  public $username = 'ab';
  function __set($key, $value) {
    if ($key = 'somekey') {
      $this->username = $value;
    }
  }
  function __get($key) {
    if ($key == 'somekey') {
      return $this->username;
    }
  }
}
// $class          = new ClassName();
// $class->somekey = 'Lionel Phạm';
// echo $class->username; // kết quả là Lionel Phạm
$class = new ClassName();
echo $class->somekey; // kết quả là ab