PHP计算程序运行时间的类

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); 
   $start = doubleval($StartMicro) + $StartSecond; 
   $stop = doubleval($StopMicro) + $StopSecond; 
   $this->TimeSpent = $stop - $start; 
   return substr($this->TimeSpent,0,8)."秒"; 
  } 
}
}//end class timer;


$timer = new timer; 
$timer->start(); 
$temp=0; 
for($i=0;$i<10000;$i++) for($j=0;$j<$i;$j++) $temp ++; 
$timer->stop(); 
echo "循环 $temp 次，运行时间为 ".$timer->spent();

//脚本运行时间
 $start_time = array_sum(explode(" ",microtime())); 
 $run_time = array_sum(explode(" ",microtime())) - $start_time; 
 echo('<center>Script Run Time: '.$run_time.'</center>');