division by zero - revisited

[ishbo]

I somewhat changed the code to make it more manageable. It now looks like this:

$testcount=0;
if (!$testg1) { $testg1 = 0; $count++; }
if (!$testg2) { $testg2 = 0; $count++; }
if (!$testg3) { $testg3 = 0; $count++; }
if (!$testg4) { $testg4 = 0; $count++; }
if (!$testg5) { $testg5 = 0; $count++; }
if (!$testg6) { $testg6 = 0; $count++; }

$testtotal = (((($testg1+$testg2+$testg3+$testg4+$testg5+$testg6) / ($testcount) 40);
$quiztotal = ((($quizg1+$quizg2+$quizg3+$quizg4+$quizg5+$quizg6) / 6) 20);
$vocabtotal = ((($vocabg1+$vocabg2+$vocabg3+$vocabg4+$vocabg5+$vocabg6) / 6) 20);
$hmwktotal = ((($hmwkg1+$hmwkg2+$hmwkg3+$hmwkg4+$hmwkg5+$hmwkg6) / 6) 10);
$journtotal = ((($journg1+$journg2+$journg3+$journg4+$journg5) / 5) * 10);

$grade = (($testtotal+$quiztotal+$vocabtotal+$hmwktotal+$journtotal) / 100)

When i try to calculate my grade using only test grades as, ironically, a test, it returns a "divison by zero error in line 14," which is the $testtotal line. It only does this when i add in the $testcount instead of 6. Can someone please tell my why this occurs?

p.s. sorry for being almost no good at php, and thank you in advance.

[ishbo]

I forgot to explain exactly what I was trying to do with this code.

Basically, I am creating a form to average a bunch of differently weighted grades together. I'm trying to make the number of grades you can enter flexible. Therefore I need to divide by the number of grades entered to get the correct average.

I'll explain further if need be.

[ishbo]

here is a link to the site :

http://cdc.frontiernetcom.com/PHP/gradecalc.php

[thna_brianb]

I dont ever see where you increment $testcount. Maybe you mean for $count to actually be $testcount.

[ishbo]

I updated the code, but I'm still getting a divide by zero error.
What did I do wrong?

Here's the whole thing:

<?php

$testcount=0;
if ($testg1 !=0) { $testcount ++; }
if ($testg2 !=0) { $testcount ++; }
if ($testg3 !=0) { $testcount ++; }
if ($testg4 !=0) { $testcount ++; }
if ($testg5 !=0) { $testcount ++; }
if ($testg6 !=0) { $testcount ++; }

$quizcount=0;
if ($quizg1 !=0) { $quizcount ++; }
if ($quizg2 !=0) { $quizcount ++; }
if ($quizg3 !=0) { $quizcount ++; }
if ($quizg4 !=0) { $quizcount ++; }
if ($quizg5 !=0) { $quizcount ++; }
if ($quizg6 !=0) { $quizcount ++; }

$vocabcount=0;
if ($vocabg1 !=0) { $vocabcount ++; }
if ($vocabg2 !=0) { $vocabcount ++; }
if ($vocabg3 !=0) { $vocabcount ++; }
if ($vocabg4 !=0) { $vocabcount ++; }
if ($vocabg5 !=0) { $vocabcount ++; }
if ($vocabg6 !=0) { $vocabcount ++; }

$hmwkcount=0;
if ($hmwkg1 !=0) { $hmwkcount ++; }
if ($hmwkg2 !=0) { $hmwkcount ++; }
if ($hmwkg3 !=0) { $hmwkcount ++; }
if ($hmwkg4 !=0) { $hmwkcount ++; }
if ($hmwkg5 !=0) { $hmwkcount ++; }
if ($hmwkg6 !=0) { $hmwkcount ++; }

$journcount=0;
if ($journg1 !=0) { $journcount ++; }
if ($journg2 !=0) { $journcount ++; }
if ($journg3 !=0) { $journcount ++; }
if ($journg4 !=0) { $journcount ++; }
if ($journg5 !=0) { $journcount ++; }
if ($journg6 !=0) { $journcount ++; }

$testtotal = ((($testg1+$testg2+$testg3+$testg4+$testg5+$testg6) / $testcount) 40);
$quiztotal = ((($quizg1+$quizg2+$quizg3+$quizg4+$quizg5+$quizg6) / $quizcount) 20);
$vocabtotal = ((($vocabg1+$vocabg2+$vocabg3+$vocabg4+$vocabg5+$vocabg6) / $vocabcount) 20);
$hmwktotal = ((($hmwkg1+$hmwkg2+$hmwkg3+$hmwkg4+$hmwkg5+$hmwkg6) / $hmwkcount) 10);
$journtotal = ((($journg1+$journg2+$journg3+$journg4+$journg5) / $journcount) * 10);

$grade = (($testtotal+$quiztotal+$vocabtotal+$hmwktotal+$journtotal) / 100)

?>

[thna_brianb]

Are you sure that each var $testcount, $quizcount, ect... have data in at least one of them ... if that is in question, simply put an if statement around your statement that averages the values i.e.

if($testcount != 0) {
$testtotal = ((($testg1+$testg2+$testg3+$testg4+$testg5+$testg6
) / $testcount) * 40);
}
else {
$testtotal = 0;
}

You would have to do this for each statement that averages the sections.

Hope this helps.

[Arc]

hmmm

[thna_brianb]

0/5 is not a divide by zero error, it is zero. anything divided by zero is a divide by zero error i.e. 5/0. The fore mentioned code should solve the problem.

[Arc]

Yah the problem is the var is empty... have it check to see if it !=0 or if it's emtpy like so..

<?php

$testcount=0;
if ($testg1 !=0 Or empty($testg1)) $testcount ++;

if ($testg2 !=0 Or empty($testg2)) $testcount ++;

if ($testg3 !=0 Or empty($testg3)) $testcount ++;
if ($testg4 !=0 Or empty($testg4)) $testcount ++;

if ($testg5 !=0 Or empty($testg5)) $testcount ++;

if ($testg6 !=0 Or empty($testg6)) $testcount ++;

$quizcount=0;
if ($quizg1 !=0 Or empty($quizg1)) $quizcount ++;

if ($quizg2 !=0 Or empty($quizg2)) $quizcount ++;

if ($quizg3 !=0 Or empty($quizg3)) $quizcount ++;

if ($quizg4 !=0 Or empty($quizg4)) $quizcount ++;

if ($quizg5 !=0 Or empty($quizg5)) $quizcount ++;
if ($quizg6 !=0 Or empty($quizg6)) $quizcount ++;

//etc...
$vocabcount=0;
if ($vocabg1 !=0) $vocabcount ++;

if ($vocabg2 !=0) $vocabcount ++;

if ($vocabg3 !=0) $vocabcount ++;

if ($vocabg4 !=0) $vocabcount ++;

if ($vocabg5 !=0) $vocabcount ++;

if ($vocabg6 !=0) $vocabcount ++;

$hmwkcount=0;
if ($hmwkg1 !=0) $hmwkcount ++;

if ($hmwkg2 !=0) $hmwkcount ++;

if ($hmwkg3 !=0) $hmwkcount ++;

if ($hmwkg4 !=0) $hmwkcount ++;

if ($hmwkg5 !=0) $hmwkcount ++;

if ($hmwkg6 !=0) $hmwkcount ++;

$journcount=0;
if ($journg1 !=0) $journcount ++;

if ($journg2 !=0) $journcount ++;

if ($journg3 !=0) $journcount ++;

if ($journg4 !=0) $journcount ++;

if ($journg5 !=0) $journcount ++;

if ($journg6 !=0) $journcount ++;

$testtotal = ((($testg1+$testg2+$testg3+$testg4+$testg5+$testg6) / $testcount) 40);
$quiztotal = ((($quizg1+$quizg2+$quizg3+$quizg4+$quizg5+$quizg6) / $quizcount) 20);
$vocabtotal = ((($vocabg1+$vocabg2+$vocabg3+$vocabg4+$vocabg5+$vocabg6) / $vocabcount) 20);
$hmwktotal = ((($hmwkg1+$hmwkg2+$hmwkg3+$hmwkg4+$hmwkg5+$hmwkg6) / $hmwkcount) 10);
$journtotal = ((($journg1+$journg2+$journg3+$journg4+$journg5) / $journcount) * 10);
$grade = (($testtotal+$quiztotal+$vocabtotal+$hmwktotal+$journtotal) / 100)

?>