Conversions/OctalToDecimal: decimalToOctal uses float division (/= 8) so it emits spurious leading zeros / over-iterates #195

Description

Conversions/OctalToDecimal.php::decimalToOctal uses floating-point division for the quotient update, so the loop produces wrong output (spurious leading zeros and a near-infinite number of iterations) for essentially every input.

function decimalToOctal($decimalNumber)
{
    ...
    $octalNumber = '';
    while ($decimalNumber > 0) {
        $octalNumber = ($decimalNumber % 8) . $octalNumber;
        $decimalNumber /= 8;          // BUG: float division, not integer division
    }
    return $octalNumber;
}

In PHP, / returns a float whenever the operands are not evenly divisible, while % casts its operands to int. So once $decimalNumber drops below 8 the quotient becomes a fraction that stays > 0 for a very long time, and each extra iteration prepends (int)fraction % 8 == 0, i.e. a spurious '0'.

Trace for decimalToOctal(8) (correct answer: "10"):

• 8 % 8 = 0 → "0"; 8 / 8 = 1 (int, evenly divisible)
• 1 % 8 = 1 → "10"; 1 / 8 = 0.125 (float)
• 0.125 > 0 is still true → (int)0.125 % 8 = 0 → "010"; 0.125 / 8 = 0.015625
• … keeps prepending '0' until the float underflows to 0

So the result is "0…010" with a long run of leading zeros (and hundreds of wasted iterations), not "10". Every value that isn't reduced to exactly 0 by integer steps is affected.

Expected behavior

decimalToOctal(8) → "10", decimalToOctal(64) → "100", decimalToOctal(1) → "1".

Actual behavior

The quotient becomes fractional, the while ($decimalNumber > 0) loop over-runs, and the output gains spurious leading zeros (e.g. decimalToOctal(8) does not return "10").

Suggested fix

Use integer division for the quotient:

$decimalNumber = intdiv((int)$decimalNumber, 8);

(or $decimalNumber = (int)($decimalNumber / 8);). A test asserting decimalToOctal(8) === "10" and decimalToOctal(64) === "100" would guard this.