[RESOLVED] show percentage of questions you got right

EPJS

Like let's say I had 100 questions, and you got 1 of them right, that's 10%. Or if I had 4 questions and you got one of them right, that's 25%.

I know how to do simple stuff like if the answer was 'B' say "you're right". But how could I do it so it sees how many answers you got right then said "you got x% correct"?

NogDog

printf("You got %d%% correct.", round($number_right / $total_number_questions * 100));

bpat1434

Well, in case you do what NogDog says, you might want to double check your percentages. 1/100 is not 10%, but 1%. And 4 out of 100 is not 25%, but 4%. Now, if you got 5 out of 25 questions right, that'd be 20%. Or if you got 1 out of 4 questions right, that's 25%.

The easy way to do this, is to do something like one form with 10 questions, then use that to get an aggregate score (X out of 10). You carry X over either via hidden fields in the next form, or via the session. At the very end, assuming you will have 10 forms (10 questions * 10 forms = 100 questions), you just add all the X values up and divide by 100 (like NogDog said).

EPJS

I tried this

$yes = ($_POST['*'] == "yes");
$total = 2;

printf("You got %d%% correct.", round($yes / $total * 100));

For the test I'm using a total of 2 questions. It doesn't matter if I answer both "yes", one "yes" or none "yes" I always get 0% as the answer

Any idea what I'm doing wrong?

Sidenote:
before when I said

Or if I had 4 questions and you got one of them right, that's 25%

I meant if I had a TOTAL of 4 question, 1 right would be 25% (I know math lol)

As for the other one, well I goofed when I thought 1 out of 100 was 10% oops :o

laserlight

$yes should contain the count of the number of questions answered correctly.

EPJS

How would I get that count? Since I can't know how many questions some visitor will get right.

laserlight

How would I get that count?

That depends on how are you collecting the answers. You need to match the answers with the correct answers. For each matching pair, you increase the count.

Since I can't know how many questions some visitor will get right.

If you really cannot find out how many questions the visitor gets correct, then by definition you cannot calculate the percentage. Of course, I think this is just a minor technical problem, rather than you really being unable to find it. 😛

EPJS

Can you figure it out? This is how I'm collecting answers.

<p>Answer the questions below</p>
<form action="quiztest2.php" method="post">
<div>
QUESTION ONE?<br />
<input name="q1" type="radio" value="yes" />Yes
<input name="q1" type="radio" value="no" />No
<br /><br />
QUESTION TWO?<br />
<input name="q2" type="radio" value="yes" />Yes
<input name="q2" type="radio" value="no" />No
<br /><br />
<input name="submit" type="submit" value="Submit" />
</div>

<?php

$yes = ($_POST['*'] == "yes");
$total = 2;

printf("You got %d%% correct.", round($yes / $total * 100));
?>

laserlight

You would do something like:

$count = 0;
if ($_POST['q1'] == 'yes') {
    ++$count;
}

if ($_POST['q2'] == 'yes') {
    ++$count;
}

// now use $count / 2 * 100 to get percentage

Of course, if you had a $_POST['q'] array instead, then you could more easily use a loop instead of explicitly listing questions.

Weedpacket

And since there is no form field named "", $_POST[''] will always be empty and a Notice message advising you of the fact would be triggered if you haven't turned them off.

EPJS

Of course, if you had a $_POST['q'] array instead, then you could more easily use a loop instead of explicitly listing questions.

And how would that look 😉
I'm not that familiar with loops

Considering the point of this was not to list them manually. If I had a thousand questions, for example, you realize how long it would take me to list them all manually? :p

laserlight

You would have HTML code along the lines of:

QUESTION ONE?<br />
<input name="q[1]" type="radio" value="yes" />Yes
<input name="q[1]" type="radio" value="no" />No
<br /><br />
QUESTION TWO?<br />
<input name="q[2]" type="radio" value="yes" />Yes
<input name="q[2]" type="radio" value="no" />No

Then to process:

$count = 0;
if (is_array($_POST['q'])) {
    foreach ($_POST['q'] as $value) {
        if ($value == 'yes') {
            ++$count;
        }
    }
}

EPJS

Thanks, that worked 🙂

bradgrafelman

Don't forget to mark this thread resolved.