<?php 
/** 
 * 定义 MyClass 
 */ 
class MyClass 
{ 
        // 构造函数必须是public 
        public function __construct() { } 
 
        // 声明一个public 的方法 
        public function MyPublic() { } 
 
        // 声明 protected 方法 
        protected function MyProtected() { } 
 
        // 声明private 方法 
        private function MyPrivate() { } 
 
        // 默认是public的 
        function Foo() 
        { 
          //类里面可以直接访问 
                $this->MyPublic(); 
                $this->MyProtected(); 
                $this->MyPrivate(); 
        } 
} 
 
$myclass = new MyClass; 
$myclass->MyPublic(); // 可以 
$myclass->MyProtected(); // 致命错误 
$myclass->MyPrivate(); //致命错误 
$myclass->Foo();    
 
 
/** 
 * 定义 MyClass2 
 */ 
class MyClass2 extends MyClass 
{ 
        //public 
        function Foo2() 
        { 
                $this->MyPublic(); 
                $this->MyProtected(); 
                $this->MyPrivate(); // 致命错误 
        } 
} 
 
$myclass2 = new MyClass2; 
$myclass2->MyPublic(); // 可以 
$myclass2->Foo2();    
 
/** 
 * 定义Bar 
 */ 
    
class Bar    
{ 
        public function test() { 
                $this->testPrivate(); 
                $this->testPublic(); 
        } 
 
        public function testPublic() { 
                echo "Bar::testPublic\n"; 
        } 
         
        private function testPrivate() { 
                echo "Bar::testPrivate\n"; 
        } 
} 
 
class Foo extends Bar    
{ 
        public function testPublic() { 
                echo "Foo::testPublic\n"; 
        } 
         
        private function testPrivate() { 
                echo "Foo::testPrivate\n"; 
        } 
} 
 
$myFoo = new Foo(); 
 
//通过继承来的公有方法Bar::test() 
$myFoo->test(); // Bar::testPrivate    
                                      // Foo::testPublic 
?>