直接看代码：

1 
     = pow(2,40)){
   #1的10次方就是1024，types到kb就是一次方，kb到mb就是二次方..类推 6         $dw = "TB"; 7     }elseif($s >= pow(2,30)){ 8         $dw = "GB"; 9     }elseif($s >= pow(2,20)){10         $dw = "MB";11     }elseif($s >= pow(2,10)){12         $dw = "KB";13     }elseif($s >= pow(1,10)){14         $dw = "types";15     }16     return $s.$dw;17 }18 echo tosize('10');19  ?>