Calculate Number of days Between two dates except saturday & sunday or week off in PHP script

<?php
$strt_date = date_create('2015-m-1');
$end_date = date_create(date('Y-m-d'));
date_sub($strt_date, date_interval_create_from_date_string('1 day'));
$interval = date_diff($strt_date, $end_date);
$num=$interval->format('%a');
$x=1;
for($i=0;$i<$num;$i++){
  date_add($strt_date, date_interval_create_from_date_string('1 day'));
  $next_day=date_format($strt_date, 'd-m-Y');
  echo "<br>";
  $new_date = new DateTime($next_day);
  $weeknum=$new_date->format('w');
  if(($weeknum!=0)&&($weeknum!=6)){
	 echo "$x. not a holiday :$weeknum  $next_day ";
	 $x++;
  }
}
?>