Help with correcting php quiz

[Maz_2014]

Could anyone help me please. I am trying to create a quiz in (quiz.php) which is works fine, but when I am trying to correct the quiz in another page (result.php) I had an error. I think the problem with posted answers and I couldn't solve it.

 

This is my code in (quiz.php):

<form method="post" action="result.php">
<?php 
session_start();

$questionNumber = 1;

$query = mysql_query("SELECT * FROM Question WHERE TID = 'TEST' order by RAND()");
while ($result = mysql_fetch_array($query)) { ?>

	 <?php echo $questionNumber . ") " . $result['Question'] . "<br>"; ?>
	 <input type="radio" name="answer<?php echo $result["QID"] ?>" value="A"> <?php echo $result['A']; ?> <br>
	 <input type="radio" name="answer<?php echo $result["QID"] ?>" value="B"> <?php echo $result['B']; ?> <br>
	 <input type="radio" name="answer<?php echo $result["QID"] ?>" value="C"> <?php echo $result['C']; ?> <br>
	 <input type="radio" name="answer<?php echo $result["QID"] ?>" value="D"> <?php echo $result['D']; ?> <br>

<?php
$questionNumber +=1;
}
?>
	  <input type="submit" name="checkQuiz" value="Check Quiz" onclick="location.href='result.php'" />
      
</form>

And This is my code in (result.php):

<?php

if(isset($_POST['checkQuiz'])) {

$correctAnswers = 0;
$wrongAnswers = 0;



$idList = join (',', array_map('intval', array_keys($_POST['answer'])));

 $sql = "SELECT QID, Answers FROM correct WHERE QID IN ($idList)";

while (list($QID, $correct) = mysql_fetch_row($res)) {

if ($correct == $_POST['answer'][$QID]) {
		 $correctAnswers +=1;
}
else {
		 $wrongAnswers +=1;
}
}
}

?>

// in the body

<?php 

$numberOfQs = $correctAnswers + $wrongAnswers;
$score = round(($correctAnswers / $numberOfQs) * 100);
?>

Correct Answers: <?php echo $correctAnswers; ?> <br>
Wrong Answers: <?php echo $wrongAnswers; ?> <br>
Score: <?php echo $score; 

?>

[ginerjm]

And the error was?

[fastsol]

Well I can see a couple things right off the bat.  Where are you defining $QID for this part?

list($QID, $correct)

And $res would be undefined since you haven't even ran the query, you only defined the query string with $sql.

[Maz_2014]

Sorry. This is the error:

 

" Warning: array_keys() expects parameter 1 to be array, null given in"

[Maz_2014]

Dear fastsol, I think this is what you mean:

<?php
if(isset($_POST['checkQuiz'])) {

$correctAnswers = 0;
$wrongAnswers = 0;



$idList = join (',', array_map('intval', array_keys($_POST['answer'])));

 $sql = "SELECT QID, Answers FROM correct WHERE QID IN ($idList)";

while($res = mysql_fetch_array( $sql ))
{

	$correct = $res['Answers'];
	$QID = $res['QID'];

if ($correct == $_POST['answer'][$QID]) {
		 $correctAnswers +=1;
}
else {
		 $wrongAnswers +=1;
}
}
}

?>

But still the same problem!!

[ginerjm]

That means read the manual and understand what that function requires.

[ginerjm]

 BTW - why do you have an onclick to direct you to the result.php script as well as a form directing the submission to the same script?  The onclick is not needed, and depending on whether it happens before the actual form submission, it may cause you problems in result.php.

[Maz_2014]

ginerjm I read the manual and the problem is whit this line:  

 

$idList = join (',', array_map('intval', array_keys($_POST['answer'])));

 

and I removed the onclick direct, but still the problem!

[ginerjm]

When you have assured yourself that you are using the proper syntax  then the problem must lie with your data.

 

If you had validated your input before trying to use it you would have caught this error.  There is NO element  $_POST['anwer'].  You do have an element in the POST array named "answer?" where ? is the value of your QID column.

[Maz_2014]

ginerjm Thank you. But could you please tell me how can I use the  $_POST['answer?'] when it is in

 

<input type="radio" name="answer<?php echo $result["QID"] ?>"

 

because I tried several ways but with out success!!

[ginerjm]

Your code is not what you think it is.  Your name attribute is the string "answer" followed immediately by the value of your QID column from your query.  So if QID for that row is "123" then your name is "answer123".  So to extract it form the post array you would have to use "$_POST['answer123'].

 

But all of this is meaningless since the whole point of radio buttons is to provide a set of choices from which the user may only choose ONE option.  This will not produce an array in $_POST, but merely a single value so your very complicated code to manage the returned value from the user is unnecessary.

[Maz_2014]

Thank you ginerjm I got your point.

 

But any suggestions for a simple code to get what I planning to do?

Edited July 4, 2014 by Maz_2014

[ginerjm]

You need to assemble your quiz form so that the answers relate to a question number.  Your attempt so far is completely wrong since you don't do that and since you are trying to gather the correct answers using the values of the selected answers from the answer table, rather than the question #.

 

If you are going to write code, learn how to (try to) separate your html from your php as much as possible.  Example:  You begin your first piece of code with an html form tag, and then jump into php mode.    Silly.  Instead - do your logic, process your input, get your data, THEN build your output

Edited July 4, 2014 by ginerjm

[fastsol]

Dear fastsol, I think this is what you mean:

<?php
if(isset($_POST['checkQuiz'])) {

$correctAnswers = 0;
$wrongAnswers = 0;



$idList = join (',', array_map('intval', array_keys($_POST['answer'])));

 $sql = "SELECT QID, Answers FROM correct WHERE QID IN ($idList)";

while($res = mysql_fetch_array( $sql ))
{

	$correct = $res['Answers'];
	$QID = $res['QID'];

if ($correct == $_POST['answer'][$QID]) {
		 $correctAnswers +=1;
}
else {
		 $wrongAnswers +=1;
}
}
}

?>

But still the same problem!!

You're still not running the query!!  You need to call mysql_query() before the while loop.