Using $_POST variable on different php pages - php

Question

EDIT: Thanks for all the helpful answers, I got it solved.
I can't really seem to find an answer to this question, and it's probably really simple.
I was just creating a page for fun where you can guess a number from 1-10. Person 1 enters a secret number, that person 2 will guess. However, I have had a lot of problems storing the $_POST from the secret number.
TL;DR I can't store the information of secretNumber into guessnumber_guessed.php file. For example look in guessnumber_guessed. First part of the if statement, if the inputNumber equals the secretNumber, it should say correct. Problem is, the variblae is undefined, how to a 'transfer the info'?
Hope you guys get my point, help is really appreciated
Here's the code:
guessnumber_welcome:
<form method="post" action="guessnumber.php">
<input type="text" name="secretNumber" placeholder="Type the secret number">
<input type="submit" name="submit" value="Send">
</form>
guessnumber.php:
<form method="post" action="guessnumber_guessed.php">
<input type="text" name="inputNumber" placeholder="Guess the secret number">
<input type="submit" name="submit" value="Guess!">
</form>
<?php
$secretNumber = $_POST["secretNumber"]
?>
guessnumber_guessed.php:
<form method="post" action="">
<input type="text" name="inputNumber" placeholder="Guess the secret number">
<input type="submit" name="submit" value="Guess!">
</form>
<?php
$inputNumber = $_POST["inputNumber"];
if ($inputNumber == $secretNumber) {
echo "<p id=\"correctAnsw\"> CORRECT! </p>";
}
else if ($inputNumber == 2) {
echo "<p id=\"wrongAnsw\">You're very close. Go up a little!</p>";
}
else if ($inputNumber==4) {
echo "<p id=\"wrongAnsw\">You're very close. Go down a little!</p>";
}
else if ($inputNumber > 10) {
echo "<p id=\"wrongAnsw\">The number is you guessed is too high. Stay within the borders!</p>";
}
else if ($inputNumber < 1) {
echo "<p id=\"wrongAnsw\">The number is you guessed is too low. Stay within the borders!</p>";
}
else {
echo "<p id=\"wrongAnsw\">This is not the number. Try a new one!</p>";
}
?>

Answer 1

The sessions will not help. They're user oriented. If the first person is using the page to enter a number and the second person comes after that, in the same session, on the same browser, you can use the sessions mechanism.
If you're trying to make a multi-user "game" and the two persons are with separate browsers, it means you must:
Pair the two persons somewhat (maybe a room mechanism)
Use some kind of server storage or cache (you can even use memcached for in-memory storage) to match the two persons and their answers.

Answer 2

I faced a similar problem trying to pass beetween two scripts some url strings for a "two-step" uploader.
In my opinion there is two solutions, depends on the level of security you want to have:
In guessnumber.php put the $_POST['secretNumber'] value in an input type="hidden"
<input type="hidden" value="<?php echo $_POST['secretNumber']; ?>">
In this way the value will be passed to the second script via POST and will be available in the $_POST array.
This method, is not safe for sensible datas, because everybody who can access the html source simply through the browser devtool can read or modify it!!
The second, and more safe, solution is to use the php session
In guessnumber.php start the php session and save the value in this way:
if ( !session_id() ) {
session_start();
}
$_SESSION['secretNumber'] = $_POST['secretNumber'];
then in guessnumber_guessed.php recover the session and get the value from there
if ( !session_id() ) {
session_start();
}
$secretNumber = $_SESSION['secretNumber'];
I strongly recommend the second solution.
Hope it helps :)