php获取当前时间之后第N个自然月最后一天的日期

<!-- lang: php -->
php获取当前时间之后第N个自然月最后一天的日期

<?php
function get_Month($num){
//获取当前的时间
$firstdate = date('Y-m-d');
$start=intval(date("m",strtotime($firstdate)));
for($i=0;$i<$num;$i++){
if(($start+$i)>12){
$result_day = date("Y-".(($start+$i)-12)."-01",strtotime("+1 year"));
}else{
$result_day = date("Y-".($start+$i)."-01",strtotime($firstdate));
}
$day = date("t",strtotime($result_day));
$result_day = date("Y-m-d",(strtotime($result_day)+($day-1)*24*3600));
}
return $result_day;
}

/**
* 功能：获得某个时间段内，所有的自然月
* @param string $date
* return array Array
*/
function getMonth(array $data){
$firstdate = $data[0];
$lastdate = $data[1];
$start=intval(date("m",strtotime($firstdate)));
$end=intval(date("m",strtotime($lastdate)));
for($i=$start;$i<=$end;$i++){
$firstday = date("Y-".$i."-01",strtotime($firstdate));
$lastday = date("Y-m-d",strtotime("$firstday +1 month -1 day"));
$result[]=array('firstday' => $i == $start?$firstdate:$firstday,'lastday'=> $i == $end?$lastdate:$lastday);
}
return $result;
}
<!-- lang: php -->
//获取当前日期后的第n个月份
function getOneMonth($sign = 0){
$tmp_date=date("Ym");
//切割出年份
$tmp_year=substr($tmp_date,0,4);
//切割出月份
$tmp_mon =substr($tmp_date,4,2);
$tmp_nextmonth=mktime(0,0,0,$tmp_mon+$sign,1,$tmp_year);
return date('Y-m',$tmp_nextmonth);
}