PHP: Elegant way to avoid division by zero

Question

Much like this site, my current project has reputation and in the script that I\'m working on I need to calculate the ratio between two users\' reputations.

Answer 1

I don’t recommend to change any user’s reputation artificially solely to make the math work. Instead you can do this:

function calc_rep_ratio($self, other)
{
    if ($self->rep != 0) {
        return $other->rep / $self->rep;
    } else {
        return NAN;
    }
}

Then use the function

$defender->ratio = calc_rep_ratio($defender, $attacker);
$attacker->ratio = calc_rep_ratio($attacker, $defender);

In the presentation, you can check for the number

if (is_nan($user->ratio)) {
    echo 'No ratio available';
} else {
    echo $user->ratio;
}