PHP中类的继承关系，PHP继承关系_PHP教程

 1 <?<span>php
 2 class<span> Father{
 3 
 4     public function<span> __construct(){
 5         echo '我是父类的构造方法!'<span>;
 6 <span>    }
 7 
 8     protected function say($str = 'Hello World!'<span>){
 9         echo '说了一句话：' . $str<span>;
10 <span>    }
11 <span>}
12 ?></span></span></span></span></span></span></span></span></span>

1 <?<span>php
2 
3 class chirld extends<span> Father{
4 
5     public<span> __construct(){
6         echo '我是子类的构造方法~'<span>;
7 <span>    }
8 }</span></span></span></span></span>

 1 <?<span>php
 2 
 3 class chirld extends<span> Father{
 4 
 5     public<span> __construct(){
 6         parent::<span>__construct();
 7         echo '我是子类的构造方法~'<span>;
 8 <span>    }
 9 <span>}
10 
11 ?></span></span></span></span></span></span></span>

1     protected function say($str = ''<span>){
2         echo '我是子类的say'<span>;
3     }</span></span>

1     public function say($str = ''<span>){
2         echo '我是子类的方法哦~'<span>;
3     }</span></span>

    public function<span> say(){
        echo '哈哈。我没有参数了耶~'<span>;
    }</span></span>