using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Sum Of Two Binary Strings");

        int rep = 1;

        while (rep != 0)

        {

            Console.WriteLine("First Number:");

            var first = Console.ReadLine();

            Console.WriteLine("Second Number:");

            var second = Console.ReadLine();

            Console.WriteLine("Sum : {0}", Calculate(first, second));

            Console.WriteLine("Do you want check more ? press 1 ");

            rep = Convert.ToInt32(Console.ReadLine());

        }

    }

​

    static string Calculate(string first, string second)

    {

        int previous = 0;

        var result = new List<string>();

        var firstLen = first.Length - 1; 

        var secondLen = second.Length - 1;

        while (firstLen >= 0 || secondLen >= 0 || previous == 1)

        {

            var f = firstLen >= 0 ? Convert.ToInt32(first[firstLen]) : 0;

            var s = secondLen >= 0 ? Convert.ToInt32(second[secondLen]) : 0;

            var temp = f % 2 + s % 2 + previous;

            result.Add((temp % 2).ToString());

            previous = temp / 2;

            firstLen--;

            secondLen--;

        }

​

        if (previous != 0)

            result.Add(previous.ToString());

        result.Reverse();

        return String.Join("", result);

    }

}