Data commit

Task/Digital-root/C-sharp/digital-root.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Linq;
+
+class Program
+{
+    static Tuple<int, int> DigitalRoot(long num)
+    {
+        int additivepersistence = 0;
+        while (num > 9)
+        {
+            num = num.ToString().ToCharArray().Sum(x => x - '0');
+            additivepersistence++;
+        }
+        return new Tuple<int, int>(additivepersistence, (int)num);
+    }
+    static void Main(string[] args)
+    {
+        foreach (long num in new long[] { 627615, 39390, 588225, 393900588225 })
+        {
+            var t = DigitalRoot(num);
+            Console.WriteLine("{0} has additive persistence {1} and digital root {2}", num, t.Item1, t.Item2);
+        }
+    }
+}