Division by Zero

Why This Happens

PHP raises this warning when you attempt to divide by zero using the / or % operators. In PHP 8+, dividing an integer by zero throws a DivisionByZeroError. This commonly occurs with user-supplied values, empty arrays used in average calculations, or counters that were never incremented.

The Problem

function average(array $numbers): float {
    return array_sum($numbers) / count($numbers);
}
echo average([]); // Division by zero

The Fix

function average(array $numbers): float {
    $count = count($numbers);
    if ($count === 0) {
        return 0.0;
    }
    return array_sum($numbers) / $count;
}

Step-by-Step Fix

1. 1

   Find the division operation

   Locate the / or % operator on the line mentioned in the error message.

2. 2

   Identify why the divisor is zero

   Check if the divisor comes from user input, a count of an empty collection, or a variable that was not properly initialized.

3. 3

   Add a zero check

   Add a conditional check to handle the zero case before the division, returning a default value or throwing a descriptive exception.