pythonLogic errorEasy

Reading keeps going after the stop marker

Time: 0:00

BugFind the bug and fix the code

What it should do

sum_until_stop(readings) adds readings until it meets -1, which means "stop". Anything after -1 is ignored. Example: sum_until_stop([3, 4, -1, 10]) → 7.

What happens instead

sum_until_stop([3, 4, -1, 10]) returns 17.

def sum_until_stop(readings):
    total = 0
    for r in readings:
        if r == -1:
            continue
        total += r
    return total

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

Hints

🏆 0 hints = Flawless Solve

Hint 2

Unlocks after Hint 1

Hint 3

Unlocks after Hint 2

This bug belongs to the logic errors pattern

The wrong operator, an inverted condition, a formula the right way round but backwards.

Learn the logic errors pattern Step through your own code

Spoiler: why this bug happens(try it first; the hints get warmer one at a time)

What went wrong: continue only skips the -1 and carries on, so the 10 after it is added.

The fix: if r == -1: break

Remember: continue skips to the next item. break leaves the loop.

The pattern behind it: logic errors.

More logic errors to practise

Embed this challenge on your site

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<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/f95a5bfa-de6f-420d-9344-c1e060a34e33">TryBugHunt</a></p>

pythonLogic errorEasy

Reading keeps going after the stop marker

Time: 0:00

BugFind the bug and fix the code

What it should do

sum_until_stop(readings) adds readings until it meets -1, which means "stop". Anything after -1 is ignored. Example: sum_until_stop([3, 4, -1, 10]) → 7.

What happens instead

sum_until_stop([3, 4, -1, 10]) returns 17.

def sum_until_stop(readings):
    total = 0
    for r in readings:
        if r == -1:
            continue
        total += r
    return total

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

Hints

🏆 0 hints = Flawless Solve

Hint 2

Unlocks after Hint 1

Hint 3

Unlocks after Hint 2

This bug belongs to the logic errors pattern

The wrong operator, an inverted condition, a formula the right way round but backwards.

Learn the logic errors pattern Step through your own code

Spoiler: why this bug happens(try it first; the hints get warmer one at a time)

What went wrong: continue only skips the -1 and carries on, so the 10 after it is added.

The fix: if r == -1: break

Remember: continue skips to the next item. break leaves the loop.

The pattern behind it: logic errors.

More logic errors to practise

Embed this challenge on your site

Paste this into any web page or blog post. Visitors fix the bug right there, in their browser.

<iframe src="https://trybughunt.com/embed/f95a5bfa-de6f-420d-9344-c1e060a34e33" title="Debugging challenge: Reading keeps going after the stop marker" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/f95a5bfa-de6f-420d-9344-c1e060a34e33">TryBugHunt</a></p>

Reading keeps going after the stop marker

What it should do

What happens instead

More logic errors to practise

Related errors

Reading keeps going after the stop marker

What it should do

What happens instead

More logic errors to practise

Related errors