PHP Warning: Division by zero

Question

I\'m learning php and built an experimental form-based calculator (also using html & POST method) that returns values to a table. The calculator is functional when I ent

Answer 1

try this

if(isset($itemCost) != '' && isset($itemQty) != '')
{
    $diffPricePercent = (($actual * 100) / $itemCost) / $itemQty;
}
else
{
    echo "either of itemCost or itemQty are null";
}

Answer 2

You need to wrap your form processing code in a conditional so it doesn't run when you first open the page. Something like so:

if($_POST['num1'] > 0 && $_POST['num2'] > 0 && $_POST['num3'] > 0 && $_POST['num4'] > 0){

  $itemQty = $_POST['num1'];
  $itemCost = $_POST['num2'];
  $itemSale = $_POST['num3'];
  $shipMat = $_POST['num4'];

  $diffPrice = $itemSale - $itemCost;
  $actual = ($diffPrice - $shipMat) * $itemQty;
  $diffPricePercent = (($actual * 100) / $itemCost) / $itemQty ;
}

Answer 3

If a variable is not set then it is NULL and if you try to divide something by null you will get a divides by zero error

Answer 4

You can try with this. You have this error because we can not divide by 'zero' (0) value. So we want to validate before when we do calculations.

if ($itemCost != 0 && $itemCost != NULL && $itemQty != 0 && $itemQty != NULL) 
{
    $diffPricePercent = (($actual * 100) / $itemCost) / $itemQty;
}

And also we can validate POST data. Refer following

$itemQty = isset($_POST['num1']) ? $_POST['num1'] : 0;

$itemCost = isset($_POST['num2']) ? $_POST['num2'] : 0;

$itemSale = isset($_POST['num3']) ? $_POST['num3'] : 0;

$shipMat = isset($_POST['num4']) ? $_POST['num4'] : 0;

Answer 5

$diffPricePercent = (($actual * 100) / $itemCost) / $itemQty;

$itemCost and $itemQty are returning null or zero, check them what they come with to code from user input

also to check if it's not empty data add:

if (!empty($_POST['num1'])) {
    $itemQty = $_POST['num1'];
}

and you can check this link for POST validation before using it in variable

https://www.virendrachandak.com/techtalk/php-isset-vs-empty-vs-is_null/

Answer 6

when my divisor has 0 value

if ($divisor == 0) {
    $divisor = 1;
}