关于php 构造函数支持不同个数参数的方法介绍

<?php
class demo{
    private $_args;
    public function __construct(){
        $args_num = func_num_args(); // 获取参数个数
        // 判断参数个数与类型
        if($args_num==2){
            $this->_args = array(
                                &#39;id&#39; => func_get_arg(0),
                                &#39;dname&#39; => func_get_arg(1)
                            );
        }elseif($args_num==1 && is_array(func_get_arg(0))){
            $this->_args = array(
                                &#39;device&#39;=>func_get_arg(0)
                            );
        }else{
            exit(&#39;func param not match&#39;);
        }    
    }
    public function show(){
        echo &#39;<pre class="brush:php;toolbar:false">&#39;;
        print_r($this->_args);
        echo &#39;

Array
(
    [id] => 1
    [dname] => fdipzone
)
Array
(
    [device] => Array
        (
            [0] => iOS
            [1] => Android
        )
)