#IPAddress different #octets #bitshifting #bitwiseor #codewars

BitShiftIPAddress.cs

using System;
using System.Linq;
public class CountIPAddresses
{
   public static long IpsBetween(string s, string e)
   {
     var start  = s.Split('.').Select(x=> Convert.ToInt32(x)).ToArray();
     var end = e.Split('.').Select(x=> Convert.ToInt32(x)).ToArray();
  
      var startAcc = start[0] << 24 | start[1] << 16  | start[2] << 8 | start[3]; 
      var endAcc = end[0] << 24 | end[1] << 16  | end[2] << 8 | end[3]; 
      return endAcc - startAcc;
    }
}

// been a loong time since I used bitwise operators.....

Best solution spotted for me:

public static long IpsBetween(string start, string end)
   {
     return (long)(uint)IPAddress.NetworkToHostOrder((int)IPAddress.Parse(end).Address) - 
            (long)(uint)IPAddress.NetworkToHostOrder((int)IPAddress.Parse(start).Address);
   }

LINQ special

public static long IpsBetween(string start, string end)
   {
        Func<string, int> fn = str => str.Split('.').Reverse().Select((s, i) => int.Parse(s) << i * 8).Aggregate(0, (current, result) => current + result);
        return fn(end) - fn(start);
   }