ISBN13 check digit: Difference between revisions
add Standard ML
Drkameleon (talk | contribs) (Added Arturo implementation) |
(add Standard ML) |
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Line 1,671:
978-1788399083: false
</pre>
=={{header|Standard ML}}==
<lang sml>local
fun check (c, p as (m, n)) =
if Char.isDigit c then
(not m, (if m then 3 * (ord c - 48) else ord c - 48) + n)
else
p
in
fun checkISBN s =
Int.rem (#2 (CharVector.foldl check (false, 0) s), 10) = 0
end
val test = ["978-1734314502", "978-1734314509", "978-1788399081", "978-1788399083"]
val () = (print
o concat
o map (fn s => s ^ (if checkISBN s then ": good\n" else ": bad\n"))) test</lang>
{{out}}
<pre>978-1734314502: good
978-1734314509: bad
978-1788399081: good
978-1788399083: bad</pre>
=={{header|Swift}}==
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