php測試代碼執行時間的類

<?php
class timer {
var $StartTime = 0;
var $StopTime = 0;
var $TimeSpent = 0;

function start(){
$this->StartTime = microtime();
}

function stop(){
$this->StopTime = microtime();
}

function spent() {
if ($this->TimeSpent) {
return $this->TimeSpent;
} else {
$StartMicro = substr($this->StartTime,0,10);
$StartSecond = substr($this->StartTime,11,10);
$StopMicro = substr($this->StopTime,0,10);
$StopSecond = substr($this->StopTime,11,10);
$start = floatval($StartMicro) + $StartSecond;
$stop = floatval($StopMicro) + $StopSecond;
$this->TimeSpent = $stop - $start;
return round($this->TimeSpent,8).'秒';
}
} // end function spent();

} //end class timer;

$timer = new timer;
$timer->start();
//測試代碼

$timer->stop();
echo '</br>運行時間為: '.$timer->spent();
unset($timer);
?>