BitExchange

using System;

namespace _16_BitExchangeAdvanced
{
    class BitExchangeAdvanced
    {
        static void Main()
        {
            uint num = 1140867093;
            byte p = 3;
            byte q = 24;
            byte k = 3;

            if (Math.Max(p,q)+k>32 || Math.Min(p,q)<0)
            {
                Console.WriteLine("out of range");
                return;
            }

            if (Math.Abs(q-p)<k)
            {
                Console.WriteLine("overlapping");
                return;
            }

            for (byte i = 0; i < k; i++)
            {
                num = BitExchange(num, p+i, q+i);
            }

            Console.WriteLine("The new value is {0}", num);

        }

        static uint BitExchange(uint num, int p, int q)
        {
            uint shiftNumP = num >> p;
            byte bitP = (byte)(shiftNumP & 1);
            uint shiftNumQ = num >> q;
            byte bitQ = (byte)(shiftNumQ & 1);

            //change bit P
            if (bitP == 0)
            {
                uint maskP =(uint) ~(1 << q);
                num = num & maskP;
            }
            else
            {
                uint maskP = (uint) (1 << q);
                num = num | maskP;
            }

            //change bit Q
            if (bitQ == 0)
            {
                uint maskQ = (uint) ~(1 << p);
                num = num & maskQ;
            }
            else
            {
                uint maskQ = (uint) 1 << p;
                num = num | maskQ;
            }

            return num;
        }
    }
}