76 lines
1.9 KiB
V
76 lines
1.9 KiB
V
const d = [
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 2, 3, 4, 0, 6, 7, 8, 9, 5],
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[2, 3, 4, 0, 1, 7, 8, 9, 5, 6],
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[3, 4, 0, 1, 2, 8, 9, 5, 6, 7],
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[4, 0, 1, 2, 3, 9, 5, 6, 7, 8],
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[5, 9, 8, 7, 6, 0, 4, 3, 2, 1],
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[6, 5, 9, 8, 7, 1, 0, 4, 3, 2],
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[7, 6, 5, 9, 8, 2, 1, 0, 4, 3],
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[8, 7, 6, 5, 9, 3, 2, 1, 0, 4],
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[9, 8, 7, 6, 5, 4, 3, 2, 1, 0],
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]
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const inv = [0, 4, 3, 2, 1, 5, 6, 7, 8, 9]
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const p = [
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 5, 7, 6, 2, 8, 3, 0, 9, 4],
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[5, 8, 0, 3, 7, 9, 6, 1, 4, 2],
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[8, 9, 1, 6, 0, 4, 3, 5, 2, 7],
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[9, 4, 5, 3, 1, 2, 6, 8, 7, 0],
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[4, 2, 8, 6, 5, 7, 3, 9, 0, 1],
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[2, 7, 9, 3, 8, 0, 6, 4, 1, 5],
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[7, 0, 4, 6, 9, 1, 3, 2, 5, 8],
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]
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fn verhoeff(ss string, validate bool, table bool) int {
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mut s:= ss
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if table {
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mut t := "Check digit"
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if validate {
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t = "Validation"
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}
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println("$t calculations for '$s':\n")
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println(" i nᵢ p[i,nᵢ] c")
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println("------------------")
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}
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if !validate {
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s = s + "0"
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}
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mut c := 0
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le := s.len - 1
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for i := le; i >= 0; i-- {
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ni := int(s[i] - 48)
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pi := p[(le-i)%8][ni]
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c = d[c][pi]
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if table {
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println("${le-i:2} $ni $pi $c")
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}
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}
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if table && !validate {
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println("\ninv[$c] = ${inv[c]}")
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}
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if !validate {
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return inv[c]
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}
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return int(c == 0)
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}
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fn main() {
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ss := ["236", "12345", "123456789012"]
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ts := [true, true, false, true]
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for i, s in ss {
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c := verhoeff(s, false, ts[i])
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println("\nThe check digit for '$s' is '$c'\n")
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for sc in [s + c.str(), s + "9"] {
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v := verhoeff(sc, true, ts[i])
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mut ans := "correct"
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if v==0 {
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ans = "incorrect"
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}
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println("\nThe validation for '$sc' is $ans\n")
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}
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}
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}
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