About Bitmap

BitMap is a useful struct, here is a simple class for get and set

 public class BitMap
    {
        private const int count = 100;
        private byte[] bitfile = new byte[count];

        public BitMap()
        {
            Init();
        }
        private void Init()
        {
            for (int i = 0; i < count; i++)
            {
                bitfile[i] = 0;
            }
        }

        public bool GetBit(int pos)
        {
            int mod = pos % 8;
            int quo = pos >> 3;
            int result = ( (int)bitfile[quo]) & (1 << mod) ;
            return Convert.ToBoolean(result);
        }

        public void SetBit(int pos, bool flag)
        {
            int mod = pos % 8;
            int quo =  pos>>3;
            int result;
            if (flag) // true == flag
            {
                result = ((int)bitfile[quo]) | (1 << mod);
            }
            else
            {
                result = ((int)bitfile[quo]) & ((1 << mod) ^ 0xFF);
            }
            bitfile[quo] = Convert.ToByte(result);
         }
    }

            BitMap bm = new BitMap();
            bm.SetBit(9, true);
            bm.SetBit(10, true);
            bm.SetBit(9, true);
            bm.SetBit(10, false);
            for (int i = 0; i < 20; i++)
            {
                Console.WriteLine("getbit : {1} : {0}", bm.GetBit(i), i);
            }