using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Threading;
using System.IO;
using System.Security.Cryptography;
using System.Collections;
using System.Net;
using System.Net.Sockets;

namespace TimeAnalyze
{
    class Program
    {
        #region Time
        //*
        static Stopwatch sw = new Stopwatch();
        static void Start()
        {
            sw.Reset();
            sw.Start();
        }
        static void Time()
        {
            Console.Error.WriteLine(sw.Elapsed);
        }
        static void Time(string text)
        {
            Console.Error.WriteLine(text + ": " + sw.Elapsed);
        }
        static void Stop()
        {
            sw.Stop();
            Time();
        }
        static void Stop(string text)
        {
            sw.Stop();
            Time(text);
        }
        //*/
        #endregion
        static object obj = new object();
        static object output = new object();
        static string host = "172.20.0.";
        static int i = 0;
        static void ThreadMethod()
        {
            int h;
            lock(obj)
            {
                h = i++;
            }
            if (h >= 65536) return;

            Socket skt = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            bool res = false;
            string host = string.Format("192.168.{1}.{0}", h & 0xFF, (h >> 2) & 0xFF);

            try
            {
                skt.Connect(host, 80);
                if (skt.Connected) res = true;
            }
            catch
            {

            }

            lock (output)
            {
                if (res)
                {
                    Console.ForegroundColor = ConsoleColor.Green;
                    File.AppendAllText("output.txt", host + "\r\n");
                    Console.Title = "Complete";
                }
                Console.WriteLine("{0} {1}", host, res);
                Console.ResetColor();
            }
        }

        static void Main(string[] args)
        {
            Thread[] threads = new Thread[1000];
            for(int i = 0; i < threads.Length; i++)
            {
                threads[i] = new Thread(() =>
                    {
                        while (i < 65536) ThreadMethod();
                    });
                threads[i].Start();
            }

            while (true) Console.ReadKey(true);
        }
    }
}