class Program {
	#region IP地址排序问题
            string strIP = File.ReadAllText("ip地址.txt");
            ////  strIP = "192.168.1.123 192.168.1.3      2.1.1.12    3.1.1.1";
            //////空格 不一致，使用正则分割
            ////string[] ipAddress = Regex.Split(strIP," +");

            #region 假设ip地址很乱，制表符不一致，通过正则提取
            MatchCollection matchColl = Regex.Matches(strIP,@"(\d{1,3}.){3}\d{1,3}");
            StringBuilder sb = new StringBuilder(50);
            foreach (Match item in matchColl)
            {
                sb.AppendLine(item.Value);
            }
            strIP = sb.ToString();
            #endregion

            string[] ipAddress = strIP.Split('\n');

            //  这样每一组的比较依据都是首个数字。与实际中ip地址分类顺序不一致了。
            Console.WriteLine("\n\n排序前：");
            Array.Sort(ipAddress);
            Console.WriteLine(string.Join("\n",ipAddress));

            #region 补0排序过程
            //补0的个数不一致，干脆都补0，保证每一组至少凑满三位
            strIP = Regex.Replace(strIP,"(\\d+)","00$1");
            //Console.WriteLine(strIP);

            //除去多余的0
            strIP = Regex.Replace(strIP,"0*(\\d{3})","$1");
            //Console.WriteLine(strIP);
            ipAddress = strIP.Split('\n');      //  补0完整后，再分割到数组

            Console.WriteLine("\n\n排序后：");
            Array.Sort(ipAddress);
            Console.WriteLine(string.Join("\n",ipAddress));
            #endregion
	#endregion
}