refactor: urfave v2

vendor/github.com/xrash/smetrics/hamming.go

@@ -0,0 +1,25 @@
+package smetrics
+
+import (
+	"fmt"
+)
+
+// The Hamming distance is the minimum number of substitutions required to change string A into string B. Both strings must have the same size. If the strings have different sizes, the function returns an error.
+func Hamming(a, b string) (int, error) {
+	al := len(a)
+	bl := len(b)
+
+	if al != bl {
+		return -1, fmt.Errorf("strings are not equal (len(a)=%d, len(b)=%d)", al, bl)
+	}
+
+	var difference = 0
+
+	for i := range a {
+		if a[i] != b[i] {
+			difference = difference + 1
+		}
+	}
+
+	return difference, nil
+}