I like to solve such tasks, I spent about 2 hours on the last ISBN10 calculation task, I won’t say that my calculation is optimal, but I always try to write my code more understandable for everyone, even if it eats a little more memory, but the experience is adaptation and optimization comes with age.

C# translation - please check and approve! By the way, nice Kata. :)

Nice kata : ) , if you want another isbn related kata then check this : https://www.codewars.com/kata/isbn-10-validation/javascript

Yes, you need to reuse the input conserving its format.

In the test, sometimes the expected isbn is in this format 000-0-00000-000-0 and sometimes it is in this format: 000-0-00-000000-0 and sometimes in this format: 000-000-00-0000-0

all of my isbns are returned in the first format so I'm failing th tests. HOw do I know which format to use for which ISBNs?

Oh I think I answered the question, because the dashes need to be in the same place as they are in the original? I was confused because I thought that ISBNs are always in the format of the first example in the tests above. I will have another go.

The description gives an exact algorithm to calculate the output from the input, what's the problem, concretely?

why are the test output ISBNs in different formats - with dashes at different places? It doesn't mention this in the output instructions.

describe "Sample tests" do
  it "Some examples" do
    expect(isbn_converter("1-85326-158-0")).to eq("978-1-85326-158-9")
    expect(isbn_converter("0-14-143951-3")).to eq("978-0-14-143951-8")
    expect(isbn_converter("0-02-346450-X")).to eq("978-0-02-346450-8")
    expect(isbn_converter("963-14-2164-3")).to eq("978-963-14-2164-4")
    expect(isbn_converter("1-7982-0894-6")).to eq("978-1-7982-0894-6")
  end
end

It looks good to me. Thank you! :)

COBOL translation.

Thanks for your quick response

Read this: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll#browser_compatibility and this: https://docs.codewars.com/training/troubleshooting#post-discourse

mmh, right. I was too much focused on the example.

edit: oh, actually, you're missing the "alternately" at the beginning of the sentence. So it seems actually correct.

The first number is multiplied by 1, the second number is multiplied by 3, the third by 1, etc. There are 1 and 3, not "or". Maybe there’s something I’m not considering.