Problem:
Sum of Numbers

Write a program which reads an integer and prints sum of its digits.

Input

The input consists of multiple datasets. For each dataset, an integer x is given in a line. The number of digits in x does not exceed 1000.

The input ends with a line including single zero. Your program should not process for this terminal symbol.

Output

For each dataset, print the sum of digits in x.

Sample Input

123
55
1000
0

Sample Output

6
10
1

Solution in C# (judge verdict: Accepted)

using System;
//using System.Collections.Generic;
//using System.Linq;
//using System.Text;
//using System.Threading;
using System.IO;
using System.Text;

//============================================================================
namespace Sweet
{
    class Program
    {
        static StreamWriter writer = null;
        //============================================================================
        static void setstdio(string[] args)
        {
            if (0 < args.Length)
            {
                // Redirect standard input from the console to the input file.
                Console.SetIn(new StreamReader(args[0]));
                if (args.Length == 2)
                {
                    // Attempt to open output file.
                    writer = new StreamWriter(args[1]);
                    // Redirect standard output from the console to the output file.
                    Console.SetOut(writer);
                }
            }
        }
        //============================================================================
        static int Swing()
        {
            int sum;
            StringBuilder builder = new StringBuilder(Console.ReadLine());
            for (int i = sum = 0; i < builder.Length; i++)
                sum += builder[i] & 0xf;
            if (sum!=0)
                Console.WriteLine(sum);
            return sum;
        }
        //============================================================================
        static void Main(string[] args)
        {
            setstdio(args);

            while(Swing()!=0);
            if (writer != null)
                writer.Close();
            //Console.ReadLine();
        }
        //============================================================================
    }
}