/************************************************
Grundlegende Algorithmen mit Java,
http://algorithmen-und-problemloesungen.de/
Copyright @2007-2008 by Doina Logofatu

in C#: Michael Gärtner
************************************************/

using System;
using System.Collections.Generic;
using System.Text;

namespace Logofatu
{
    class P1DigitsSumAndReverse
    {
        private static long sumDigits(long number)
        {
            return number == 0 ? number : number % 10 + sumDigits(number / 10);
        }

        private static long noDigits(long number)
        {
            return number == 0 ? number : 1 + noDigits(number / 10);
        }

        private static long pow(long basis, long exp)
        {
            return exp == 0 ? 1 : basis * pow(basis, exp - 1);
        }

        private static long reverse(long number)
        {
            return number == 0 ? 0 : 
                ((number % 10)*pow(10,noDigits(number)-1)+reverse(number/10));
        }     


        static void Main(string[] args)
        {
            Console.Write("n= ");
            long n = long.Parse(Console.ReadLine());
            Console.Write("sumDigits(n)= ");
            Console.WriteLine(sumDigits(n));
            Console.Write("reverse(n)= ");
            Console.WriteLine(reverse(n));

            // warte, bis Taste gedrückt
            Console.ReadLine();
        }
    }
}