Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the infinite loops pattern
The tab freezes, nothing prints, and the loop condition never becomes false.
What went wrong: n % 10 reads the last digit, but n never changes. n stays 123, so the loop never ends.
The fix: add n //= 10 inside the loop, after the addition.
Remember: to walk through digits, read the last one with % 10, then remove it with // 10.
The pattern behind it: infinite loops.
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<iframe src="https://trybughunt.com/embed/91ccc9a1-d5a1-42f7-b8d8-bff1adf9040d" title="Debugging challenge: Adding up digits never finishes" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
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