isbn-verifier: a check digit can only be one character#2604
Merged
glennj merged 1 commit intoexercism:mainfrom Oct 31, 2025
Merged
isbn-verifier: a check digit can only be one character#2604glennj merged 1 commit intoexercism:mainfrom
glennj merged 1 commit intoexercism:mainfrom
Conversation
BNAndras
approved these changes
Oct 30, 2025
kotp
approved these changes
Oct 30, 2025
ErikSchierboom
approved these changes
Oct 31, 2025
kahgoh
added a commit
to kahgoh/exercism-java
that referenced
this pull request
Oct 31, 2025
This updates the exercise with new test cases from exercism/problem-specifications#2604 and exercism/problem-specifications#2601.
jagdish-15
pushed a commit
to exercism/java
that referenced
this pull request
Oct 31, 2025
This updates the exercise with new test cases from exercism/problem-specifications#2604 and exercism/problem-specifications#2601.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
A check digit can only be one character, even if the "sum" is divisible by eleven.
Given
3-598-21508-96, suppose we take the weighted sum of the first 9 digits and then add the remaining digits as the "check digit":$ sh -c 'echo $(( (10*3 + 9*5 + 8*9 + 7*8 + 6*2 + 5*1 + 4*5 + 3*0 + 2*8 + 96) % 11 ))' 0It should still be invalid for violating the description:
Forum: http://forum.exercism.org/t/yet-another-isbn-edge-case-found/19787