Comparing values from multiple text boxes with mysql table

Question

I am trying to implement a form in which a user is asked some questions which are stored in a database. The answers for the respective questions is also stored and the user to supposed to answer those in the text boxes provided (like an online test system). I want to store all the answers entered by the user in an array, while storing the values of the answer column of the database in another array. Comparing the values of the two arrays should give me the number of right answers. I referred to this question and have used the following codes. But the problem is that the result is showing an undefined offset error at the place where I use variable $i to compare the two arrays. Please help me.

Code for form (giveexam.php):

<form id ="answersheet" name="answersheet" action="assessment.php" method="post">
<table border="1px">
<tr>
<!--td>sr_no</td-->
<td width="144">Question</td>
<td width="50">option1</td>
<td width="50">option2</td>
<td width="50">option3</td>
<td width="50">option4</td>
<td width="30">
<strong>ANSWER</strong></td>


</tr>
<?php
require_once("connection.php");

$query = "select * from mgmt";
$result = mysql_query($query, $connection);

if(!$result)
echo "ERROR: No results";
else
{
while($row = mysql_fetch_array($result))
{

?>

<tr>
<!--td><?php echo $row['eid'];?></td-->
<td><?php echo $row['question'];?></td>
<td><?php echo $row['op1'];?></td>
<td><?php echo $row['op2'];?></td>
<td><?php echo $row['op3'];?></td>
<td><?php echo $row['op4'];?></td>
<td><input type="text" name="ans[]"/></td>

</tr>


<?php }
} //end while
?>
</table>
<tr>

<td></td>
<td><input type="submit" value="submit" /></td>
</tr>
</form>

PHP file (assessment.php):

<?php
session_start();
$m=0;
//$c=0;

            require_once("connection.php");

            $query="select answer from mgmt";
            $result=mysql_query($query, $connection);

            $result_array=array();
            while($row=mysql_fetch_assoc($result))
            {$result_array[]=$row;}

            $answer=array();
            $answer[]=$_POST["ans"];
            for($i=1;$i<4;$i++)
            {
                if($answer[$i]==$result_array[$i])
                    $m++;

            }
            echo $m;

                    ?>

**DO NOT USE THE `mysql_` EXTENSION FOR NEW CODE AS IT IS NOW DEPRECATED. USE `PDO` OR `MySQLi` INSTEAD.** — Ethan, Nov 12 '13 at 18:52
Possible duplicate of [PHP: "Notice: Undefined variable", "Notice: Undefined index", and "Notice: Undefined offset"](https://stackoverflow.com/questions/4261133/php-notice-undefined-variable-notice-undefined-index-and-notice-undef) — Matt S, Sep 12 '17 at 13:33

score 0 · Answer 1 · answered Nov 12 '13 at 19:02

0

undefined offset means that either the $answer or the $result_array is shorter than 4. try printing the results first and see where the problem lays.

answered Nov 12 '13 at 19:02

Adi Scoarta

36
2

okay, I tried it, and printing the values for the `$result_array` is giving me the `array to string conversion` error. maybe i'm not entering values from the column into the array right. any suggestions? – Ayush Khemka Nov 12 '13 at 19:12
made the following changes in assessment.php file: 1. It is simply `$answer=$_POST["ans"];` without the `$answer=array();` 2. Additionally, used `$result_array[]=$row['answer'];` instead of `$result_array[]=$row;` cannot post any more answers from this account :( – Ayush Khemka Nov 12 '13 at 19:24
to print the values, use the `echo "
```
";var_dump($var);echo"
```
";` to see the actual variable and it's format(it might be anything from string to object). And yeah, in the current form, $answer[0] contains the $_POST so it's exactly 1 in length:)
– Adi Scoarta Nov 12 '13 at 19:31

Comparing values from multiple text boxes with mysql table

1 Answers1