本文共 1692 字，大约阅读时间需要 5 分钟。

php的继承功能还很不完善，并且很容易出错。运行下面的代码，看看结果是否是你所要的。

<?php interface IA { public function Print1(); public function Print2(); //private function Pritn3(); //error //public $m_var1; //error }; abstract class CB { public abstract function Echo1(); //private abstract function Echo2(); //error public function Echo3() { echo "CB::Echo3<br>"; echo "m_var1 = " . $this->m_var1 . "<br>"; echo "m_var2 = " . $this->m_var2 . "<br>"; echo "m_var3 = " . $this->m_var3 . "<br>"; echo "m_var4 = " . $this->m_var4 . "<br>"; echo "m_var = " . CB::m_var . "<br>"; echo "static m_var3 = " . CB::$m_var3 . "<br>"; } public $m_var1; private $m_var2; public static $m_var3 = 11; protected $m_var4; const m_var = 10; //声明为常量 }; class CC implements IA { public function CC() { echo "constructor of CC has been called!<br>"; } public function __destructor() { echo "destructor of CC has been called!<br>"; } function Print1() { echo "CC::Print1()<br>"; } function Print2() { echo "CC::Print2()<br>"; } }; class CD extends CB { public function CD() { echo "constructor of CD has been called!<br>"; //parent::$m_var1 = 1; //error $this->m_var1 = 1; $this->m_var2 = 2; //因为父类中位private所以，无法直接去访问。因此，隐式的定义了一个变量 $this->m_var3 = 3; $this->m_var4 = 4; $this->m_var = 5; } function Echo1() { echo "CD::Echo1()<br>"; } };?><?php //$objA = new IA; //$objB = new CB; $objC = new CC; $objD = new CD; $objC->Print1(); $objC->Print2(); $objD->Echo1(); $objD->Echo3();?> 

结果：

constructor of CC has been called!

转载地址：http://abpcb.baihongyu.com/