ISBN13 check digit: Difference between revisions
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for .key in sort(keys .tests) { |
for .key in sort(keys .tests) { |
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val .pass = .isbn13checkdigit(.key) |
val .pass = .isbn13checkdigit(.key) |
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write .key, ": ", .pass |
write .key, ": ", if(.pass: "good"; "bad") |
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writeln if(.pass == .tests[.key]: ""; " (ISBN-13 CHECK DIGIT TEST FAILED)") |
writeln if(.pass == .tests[.key]: ""; " (ISBN-13 CHECK DIGIT TEST FAILED)") |
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}</lang> |
}</lang> |
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{{out}} |
{{out}} |
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<pre>978-1734314502: |
<pre>978-1734314502: good |
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978-1734314509: |
978-1734314509: bad |
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978-1788399081: |
978-1788399081: good |
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978-1788399083: |
978-1788399083: bad</pre> |
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Revision as of 17:11, 4 December 2019
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Validate the check digit of an ISBN-13 code. Use some good and bad codes of your choosing for testing.
Multiply every other digit by 3. Add the digits together. Take the remainder of division by 10. If it is 0, the ISBN-13 check digit is correct.
- See also
See https://isbn-information.com/the-13-digit-isbn.html for details on the method of validation.
langur
<lang langur>val .isbn13checkdigit = f(.n) {
val .s = replace(.n, "-", "")
if len(.s) != 13 {
return false
}
# multiply every other number by 3
val .nums = map(
f(.i, .d) if(.i rem 2 == 0: .d x 3; .d),
series(13),
map f .c-'0', s2cp .s,
)
fold(f .x + .y, .nums) rem 10 == 0
}
val .tests = h{
"978-1734314502": true, "978-1734314509": false, "978-1788399081": true, "978-1788399083": false,
}
for .key in sort(keys .tests) {
val .pass = .isbn13checkdigit(.key) write .key, ": ", if(.pass: "good"; "bad") writeln if(.pass == .tests[.key]: ""; " (ISBN-13 CHECK DIGIT TEST FAILED)")
}</lang>
- Output:
978-1734314502: good 978-1734314509: bad 978-1788399081: good 978-1788399083: bad