Division by zero laravel

Question

I have a percentage calculation, but if no data is available, I get the following error message:

Division by zero

calculation

$ratio = ($postup*100)/($postup + $postdown);

Answer 1

Devision by zero is undefined.

If both $postup and $postdown are null (not set) you will get a division by zero i.e. null + null == 0.

Furthermore the same problem will occur if $postup * -1 == $postdown.

Since a division by zero is undefined you will need to add a fallback for this.

What this fallback would be is application specific but would look something like

$ratio = null;

if($postup + $postdown == 0) {
    $ratio = xxx;
} else {
    $ratio = ($postup*100)/($postup + $postdown);
}

Please also be aware that $postup * 100 will be equal to 0 if $postup == null