Add digits answer

Author: tinycedar

Diff for: add-digits.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+)
+
+func addDigits(num int) int {
+	for num >= 10 {
+		sum := 0
+		for ; num > 0; num /= 10 {
+			sum += num % 10
+		}
+		num = sum
+	}
+	return num
+}
+
+func main() {
+	fmt.Println(addDigits(10))
+}