PHP session variable only increments once

Question

I've been fiddling with PHP recently along with databases and I've come across a problem where I when I want to increment a session variable, question_id within an if statement it will increment once and not increment thereafter.

session_start();
$_SESSION['question_id'] = 11; // Set default var

if(isset($_POST['ans'])) {
    if($funcs->checkAnswer($_SESSION['question_id'], $mysqli)) {
        $_SESSION['question_id'] = $_SESSION['question_id'] + 1;
    }
}

$question = $funcs->getQuestion($_SESSION['question_id'], $mysqli);

The $_POST variable ans is the ID of a form where the user puts their answer, this answer is checked against the correct answer in the database by checkAnswer() which grabs the correct answer and compares it to the users' answer, if correct it returns true, else false. If checkAnswer() is true, in theory the session variable question_id should increment each time and thus update the question, however it does this only once then after this it stays on the first iteration of the increment (question 2), and if the answer inputted by the user is wrong, it resets back to question one for some reason.

Does anyone know why the $_SESSION['question_id'] only increments once even though the if statement is true? If you can see where the reset problem lies also that'd be great but I'll probably create a new post for that.

Thanks in advance.

Because the first thing you seem to do is reset it to 11 on every request... — Jonnix
– Jonnix, Commented Jun 29, 2016 at 15:09

ManfredP · Accepted Answer · 2016-06-29 15:11:25Z

2

You always reset your question_id to 11. You have to write:

if (empty($_SESSION['question_id']) {
    $_SESSION['question_id'] = 11;
}

answered Jun 29, 2016 at 15:11

ManfredP

1,0471 gold badge13 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Shira · Accepted Answer · 2016-06-29 15:11:38Z

0

You are executing $_SESSION['question_id'] = 11; on every request to "set default var" and then increment it once if the two conditions pass. Why are you expecting it to ever be higher than 12?

If you don't want to overwrite the value each time, you'll have to check it with isset:

if (!isset($_SESSION['question_id'])) {
    $_SESSION['question_id'] = 11;
}

Also you can do:

++$_SESSION['question_id'];

Instead of:

$_SESSION['question_id'] = $_SESSION['question_id'] + 1;

answered Jun 29, 2016 at 15:11

Shira

6,5892 gold badges27 silver badges28 bronze badges

2 Comments

mitkosoft Over a year ago

I'm just curious what is the difference to perform ++$var instead of $var++ in that particular case when this variable is not involved anywhere else?

Shira Over a year ago

++$var increments the variable and then returns the new value, $var++ stores the current value, increments the variable and returns the previously stored value. If you don't need the behavior of $var++ it's a tiny bit faster to use ++$var.

meteorite · Accepted Answer · 2016-06-29 15:12:40Z

0

You are re-setting the value of $_SESSION['question_id'] each time the script gets executed. This is why it will only increment once. You should check it first like this:

<?php
session_start();

if( !isset($_SESSION['question_id']) )
{
  $_SESSION['question_id'] = 11; // Set default var
}

if(isset($_POST['ans'])) {
    if($funcs->checkAnswer($_SESSION['question_id'], $mysqli)) {
        $_SESSION['question_id'] = $_SESSION['question_id'] + 1;
    }
}

$question = $funcs->getQuestion($_SESSION['question_id'], $mysqli);

This way you prevent the session var being set repeatedly.

answered Jun 29, 2016 at 15:12

meteorite

7661 gold badge8 silver badges17 bronze badges

Collectives™ on Stack Overflow

PHP session variable only increments once

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related