如何解决php倒计时出现-0的情况

$starttime   = 1362585600; //3.7凌晨
$nowtime   = 1362618921;//3.7早上
$off = ceil(($starttime - $nowtime)/86400); //倒计时
if ($off < 0) {
  $off = 0;
}
$b = $starttime - $nowtime;
$c = $b/86400;
$d = ceil($c);
var_dump(array(&#39;start-now&#39;=>$b), array(&#39;float_day&#39;=>$c), array(&#39;int_day&#39;=>$d), array(&#39;off&#39;=>$off));
if (-0 < 0) {
  echo &#39;-0 < 0&#39;;
} else {
  echo &#39;-0 > 0&#39;;
}

array
 'start-now' => int -33321
array
 'float_day' => float -0.385659722222
array
 'int_day' => float -0
array
 'off' => float -0
-0 > 0

$starttime   = 1362585600; //3.7凌晨
$nowtime   = 1362618921;//3.7早上
if (($starttime - $nowtime) < 0) {
  $off = 0;
} else {
  $off = ceil(($starttime - $nowtime)/86400);
}