Show Difference In Days Between Two Dates

DifferenceInDays.php

 <?php

class DifferenceInDays {
    private $difference;
    protected $start;
    protected $end;

    function __construct($startDateTime, $endDateTime) {
        if (is_string($startDateTime))
            $this->start = date_create($startDateTime);
        if (is_string($endDateTime))
            $this->end = date_create($endDateTime);
    }

    public function GetDifferenceInDays() {
        $this->difference = date_diff($this->start, $this->end);
        $total            = $this->difference->y * 365.25 + $this->difference->m * 30 + $this->difference->d + $this->difference->h / 24 + $this->difference->i / 60;
        return ($this->difference->invert) ? -1 * $total : $total;
    }

}

$obj = new DifferenceInDays('2011-01-01', '2011-01-23');
print $obj->GetDifferenceInDays() . "\n";
?>