程序代码：

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

namespace ConsoleApplication19
{
    class Program
    {
        static void Main(string[] args)
        {
            string a = "0001100";

            char combine;

            char[] c = a.ToCharArray();

            Array.Reverse(c);

            for(int i=0;i<c.Length;i++)
            {
                if (c[i] == 0)
                {
                    continue;
                }
                else if (c[i] == 1)
                {
                    combine &= 1 << c[i];
                }
                else { break; }
            }
            Console.Read();
        }
    }
}