PHP面试题之设计模式，php试题设计模式_PHP教程

<span>/*</span><span>*
 * 单例模式
 * 
 </span><span>*/</span>
<span>class</span><span> Config
{
    </span><span>static</span> <span>private</span> $_instance =<span> NULL;
    </span><span>private</span> $_settings =<span> array();
    </span><span>private</span><span> function __construct(){}
    </span><span>private</span><span> function __clone(){};

    </span><span>static</span><span> function getInstance()
    {
        </span><span>if</span>(self::$_intance ==<span> NULL){
            self::$_intance </span>= <span>new</span><span> Config();
        }
        </span><span>return</span><span> self:$_intance;
    }

    </span><span>public</span> function <span>set</span><span>($index,$value)
    {
        $</span><span>this</span>->_setting[$index] =<span> $value;
    }

    </span><span>public</span> function <span>get</span><span>($index)
    {
        </span><span>return</span> $<span>this</span>-><span>_settings[$index];
    }
}</span>