doocs/leetcode · error · Exception

Can not divide by 0

Error message

Can not divide by 0

What it means

English README variant of the same PHP LeetCode 29 solution: divide($a, $b) throws Exception('Can not divide by 0') when $b == 0. It exists because the algorithm assumes a non-zero divisor per problem constraints and guards the boundary explicitly before performing subtraction-based division.

Source

Thrown at solution/0000-0099/0029.Divide Two Integers/README_EN.md:267

        }
        return sign ? ans : -ans;
    }
}
```

#### PHP

```php
class Solution {
    /**
     * @param integer $a
     * @param integer $b
     * @return integer
     */

    function divide($a, $b) {
        if ($b == 0) {
            throw new Exception('Can not divide by 0');
        } elseif ($a == 0) {
            return 0;
        }
        if ($a == -2147483648 && $b == -1) {
            return 2147483647;
        }
        $sign = $a < 0 != $b < 0;

        $a = abs($a);
        $b = abs($b);
        $ans = 0;
        while ($a >= $b) {
            $x = $b;
            $cnt = 1;
            while ($a >= $x << 1) {
                $x <<= 1;
                $cnt <<= 1;
            }

View on GitHub (pinned to f84f361dc4)

Solutions

1. Guard the call site: if ($b == 0) return a sentinel or error instead of calling
2. Filter zero divisors out of test-case generators
3. Wrap in try/catch (Exception) if the value legitimately comes from untrusted input
4. Remember return 0 shortcut when $a == 0 — only $b == 0 throws

Example fix

// before
echo divide(7, 0); // throws 'Can not divide by 0'

// after
function safeDivide(int $a, int $b): ?int {
    return $b === 0 ? null : divide($a, $b);
}

$b = (int)$input; if ($b === 0) { fwrite(STDERR, "divisor must be non-zero\n"); exit(1); } divide($a, $b);

function isNonZeroDivisor(mixed $v): bool { return is_int($v) && $v !== 0; }

try { divide(7, $b); } catch (Exception $e) { /* 'Can not divide by 0' */ }

When it happens

Trigger: Running the documented snippet with $b = 0, $b = '0', or $b = 0.0 (loose == matches all); test scripts that sweep divisors including zero.

Common situations: Copy-pasting the README code into a local runner and passing edge-case inputs; PHP 8 strictness changes making unguarded division fatal; assuming the overflow branch (PHP_INT_MIN / -1) is the only special case to handle.

Related errors

• Can not divide by 0
• Can not divide by 0
• Division by zero is not allowed
• Division by zero is not allowed
• Division by zero is not allowed

AI-assisted analysis of doocs/leetcode@f84f361dc4 (2026-08-27). Data as JSON: /api/errors/686d0f0e16132c74. Report an issue: GitHub.