Data commit

Task/Verhoeff-algorithm/Go/verhoeff-algorithm.go

@@ -0,0 +1,78 @@
+package main
+
+import "fmt"
+
+var d = [][]int{
+    {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
+    {1, 2, 3, 4, 0, 6, 7, 8, 9, 5},
+    {2, 3, 4, 0, 1, 7, 8, 9, 5, 6},
+    {3, 4, 0, 1, 2, 8, 9, 5, 6, 7},
+    {4, 0, 1, 2, 3, 9, 5, 6, 7, 8},
+    {5, 9, 8, 7, 6, 0, 4, 3, 2, 1},
+    {6, 5, 9, 8, 7, 1, 0, 4, 3, 2},
+    {7, 6, 5, 9, 8, 2, 1, 0, 4, 3},
+    {8, 7, 6, 5, 9, 3, 2, 1, 0, 4},
+    {9, 8, 7, 6, 5, 4, 3, 2, 1, 0},
+}
+
+var inv = []int{0, 4, 3, 2, 1, 5, 6, 7, 8, 9}
+
+var p = [][]int{
+    {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
+    {1, 5, 7, 6, 2, 8, 3, 0, 9, 4},
+    {5, 8, 0, 3, 7, 9, 6, 1, 4, 2},
+    {8, 9, 1, 6, 0, 4, 3, 5, 2, 7},
+    {9, 4, 5, 3, 1, 2, 6, 8, 7, 0},
+    {4, 2, 8, 6, 5, 7, 3, 9, 0, 1},
+    {2, 7, 9, 3, 8, 0, 6, 4, 1, 5},
+    {7, 0, 4, 6, 9, 1, 3, 2, 5, 8},
+}
+
+func verhoeff(s string, validate, table bool) interface{} {
+    if table {
+        t := "Check digit"
+        if validate {
+            t = "Validation"
+        }
+        fmt.Printf("%s calculations for '%s':\n\n", t, s)
+        fmt.Println(" i  nᵢ  p[i,nᵢ]  c")
+        fmt.Println("------------------")
+    }
+    if !validate {
+        s = s + "0"
+    }
+    c := 0
+    le := len(s) - 1
+    for i := le; i >= 0; i-- {
+        ni := int(s[i] - 48)
+        pi := p[(le-i)%8][ni]
+        c = d[c][pi]
+        if table {
+            fmt.Printf("%2d  %d      %d     %d\n", le-i, ni, pi, c)
+        }
+    }
+    if table && !validate {
+        fmt.Printf("\ninv[%d] = %d\n", c, inv[c])
+    }
+    if !validate {
+        return inv[c]
+    }
+    return c == 0
+}
+
+func main() {
+    ss := []string{"236", "12345", "123456789012"}
+    ts := []bool{true, true, false, true}
+    for i, s := range ss {
+        c := verhoeff(s, false, ts[i]).(int)
+        fmt.Printf("\nThe check digit for '%s' is '%d'\n\n", s, c)
+        for _, sc := range []string{s + string(c+48), s + "9"} {
+            v := verhoeff(sc, true, ts[i]).(bool)
+            ans := "correct"
+            if !v {
+                ans = "incorrect"
+            }
+            fmt.Printf("\nThe validation for '%s' is %s\n\n", sc, ans)
+        }
+    }
+}