分享下php5类中三种数据类型的区别

<?php
/**
 * parent　只能调用父类中的公有或受保护的方法，不能调用父类中的属性
 * self 　可以调用父类中除私有类型的方法和属性外的所有数据
 */
class User{
 public $name;
 private $passwd;
 protected $email; 
 public function __construct(){
  //print __CLASS__." ";
  $this->name= 'simple';
  $this->passwd='123456';
  $this->email = 'bjbs_270@163.com';
 } 
 public function show(){
  print "good ";
 } 
 public function inUserClassPublic() {
  print __CLASS__.'::'.__FUNCTION__." ";
 } 
 protected function inUserClassProtected(){
  print __CLASS__.'::'.__FUNCTION__." ";
 } 
 private function inUserClassPrivate(){
  print __CLASS__.'::'.__FUNCTION__." ";
 }
}

class simpleUser extends User { 
 public function __construct(){  
  //print __CLASS__." ";
  parent::__construct();
 }
 
 public function show(){
  print $this->name."//public ";  
  print $this->passwd."//private ";
  print $this->email."//protected ";
 }
 
 public function inSimpleUserClassPublic() {
  print __CLASS__.'::'.__FUNCTION__." ";
 }
 
 protected function inSimpleUserClassProtected(){
  print __CLASS__.'::'.__FUNCTION__." ";
 }
 
 private function inSimpleUserClassPrivate() {
  print __CLASS__.'::'.__FUNCTION__." ";
 }
}

class adminUser extends simpleUser {
 protected $admin_user;
 public function __construct(){
  //print __CLASS__." ";
  parent::__construct();
 }
 
 public function inAdminUserClassPublic(){
  print __CLASS__.'::'.__FUNCTION__." ";
 }
 
 protected function inAdminUserClassProtected(){
  print __CLASS__.'::'.__FUNCTION__." ";
 }
 
 private function inAdminUserClassPrivate(){
  print __CLASS__.'::'.__FUNCTION__." ";
 }
}

class administrator extends adminUser {
 public function __construct(){  
  parent::__construct();
 }
}

/**
 * 在类的实例中 只有公有属性和方法才可以通过实例化来调用
 */
$s = new administrator();
print '-------------------';
$s->show();
?>