function start()
    {
        $this->starttime=$this->getmicrotime();
    }

    function display()
    {
        $this->stoptime=$this->getmicrotime();
        $this->spendtime=$this->stoptime-$this->starttime;
        echo "
Processed in". round($this->spendtime,6)."second(s). 
";
     }
}
//实例化时间类
$time=new lib_times();
$time->start();
//要计算时间的部分
function NumToStr($nStr)
{
	$arr = array("0" =>"A","1" =>"B","2" =>"C","3" =>"D","4" =>"E","5" =>"F","6" =>"G","7" =>"H","8" =>"I","9" =>"J");
    return strtr($nStr,$arr);
}
function NumToStr1($nstr)
{
	return strtr($nstr,'0123456789','abcdefghij');

}
$str="12312331342424";
print_r(NumToStr($str));
//print_r(NumToStr1($str));

//计算结果显示
$time->display();


?>