I have a minor problem where my code store the value and can run as usual, but when I want to display it again, the value won't display and the error is:
Notice: Undefined variable: result_c in C:\\xampp\\htdocs\\eAttendance\\*******.***php on line 91
Which is:
<td><?php echo $GLOBALS['result_c'] ?></td>
My question is:
$result_c
? I made this code because I wanted to calculate all the values in array stored inside $result_c
to become average percentage of attendance.
<table >
<tr>
<td>Matrix Card</td>
<td>Percent</td>
</tr>
<?php
$sbj = $_GET['sbj'];
$cls = $_GET['cls'];
$sql = mysql_query ("SELECT * FROM stu_course where class = '$cls' and subject_code = '$sbj'");
$a = 0;
while ($row = mysql_fetch_assoc($sql)){
?>
<tr>
<?php
$result1[] = $row['login_id'];
$sql1 = mysql_query("Select * from attendance where id_student = '$result1[$a]' and subject_code = '$sbj'") or die('Query failed. ' . mysql_error());
$b = 0;
while($row1 = mysql_fetch_assoc($sql1))
{
$popo = 1;
$result_array[] = $row1['credit_hour'];
$add = $result_array[$b];
$result_c = $result_c + $add;
}?>
<td><?php echo $result1[$a];?></td>
<td><?php echo $GLOBALS['result_c'] ?></td>
<?php
$a++;
}
?>
</tr>
</table>
Instead of <?php echo $GLOBALS['result_c'] ?>
why can't you just output <?php echo $result_c ?>
? Or am I not understanding correctly.
Also I would use prepared statements. Here is an example: http://forums.phpfreaks.com/topic/285929-pdo-in-a-php-class/#entry1467894
It seems you are injecting data straight from the client into your db call leaving you wide open to attack!
Try declaring $result_c
outside the while loop, so you don't have to use $GLOBALS
to cope with the variable scope issue you're having. Furthermore, the use of $GLOBALS isn't recommended.
Extra advise: I'd recommend working on your naming conventions so we can understand your code easier.
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