Calculating difference between days * price per day = value PHP [closed] - php

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Closed 9 years ago.
I'm currently working on a little form that allows people to book a stay at a hostel. Basicly, I get them to pick two dates. (Day of arrival & day of departure) Then I want to calculate the difference between those dates in days, and finally I want to multiply the number of days with the price per day.
I can't seem to figure out how to calculate the days * price per day and pass that string on to the "amount value" in my form.
This is what I got so far:
<input type="text" id="datepicker" value="arrival (day-month-year)" />
<input type="text" id="datepicker2" value="departure (day-month-year)" />
<form action="checkout.php" method="post">
<input name="amount" type="hidden" value="$dateDiff * price per day = value">
<input type="submit" value="Check out" id="checkout">
</form>
And my PHP
<?php
$date1 = ("#datepicker");
$date2 = ("#datepicker2");
$dateDiff = $date1 - $date2;
$fullDays = floor($dateDiff/(60*60*24));
echo "Difference is $fullDays days";
?>
Edit: After the first two comments, let me explain that I'm fairly new to PHP. Thanks.

Answer 1

You have to put the input fields in your form and give it a name likes this:
<form action="checkout.php" method="post">
<input type="text" id="datepicker" name="datepicker" value="arrival (day-month-year)" />
<input type="text" id="datepicker2" name="datepicker2" value="departure (day-month-year)" />
<input name="amount" type="hidden" value="$dateDiff * price per day = value">
<input type="submit" value="Check out" id="checkout">
</form>
Now in your PHP file:
<?php
if(isset($_POST["datepicker"], $_POST["datepicker2"])){
$date1 = new DateTime($_POST["datepicker"]);
$date2 = new DateTime($_POST["datepicker2"]);
$diff = $date1->diff($date2);
$amount_per_day = 10; // for example 10 dollars
$total = floor($diff["days"]) * $amount_per_day; // total
}
?>

Answer 2

The datetime object offers a diff function:
http://php.net/manual/en/datetime.diff.php
$datetime1 = new DateTime('2009-10-11');
$datetime2 = new DateTime('2009-10-13');
$interval = $datetime1->diff($datetime2);
print_r($interval);
DateInterval Object
(
[y] => 0
[m] => 0
[d] => 2
[h] => 0
[i] => 0
[s] => 0
[invert] => 0
[days] => 2
)
So you could calculate your price with
$price = $pricePerDay * $interval->days;

Answer 3

Try this:
function dateDiff($start, $end)
{
$start_ts = strtotime($start);
$end_ts = strtotime($end);
$diff = $end_ts - $start_ts;
return round($diff / 86400);
}