Network C# Tutorial

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class EmployeeClient
{
   public static void Main()
   {
      Employee emp1 = new Employee();
      Employee emp2 = new Employee();
      TcpClient client;
      emp1.ID = 1;
      emp1.LastName = "D";
      emp1.FirstName = "C";
      emp1.YearsService = 12;
      emp1.Salary = 35.50;
      emp2.ID = 2;
      emp2.LastName = "B";
      emp2.FirstName = "A";
      emp2.YearsService = 9;
      emp2.Salary = 23.30;
      client = new TcpClient("127.0.0.1", 9050);
      NetworkStream ns = client.GetStream();
      byte[] data = emp1.GetBytes();
      int size = emp1.size;
      byte[] packsize = new byte[2];
      packsize = BitConverter.GetBytes(size);
      ns.Write(packsize, 0, 2);
      ns.Write(data, 0, size);
      ns.Flush();
      data = emp2.GetBytes();
      size = emp2.size;
      packsize = new byte[2];
      packsize = BitConverter.GetBytes(size);
      ns.Write(packsize, 0, 2);
      ns.Write(data, 0, size);
      ns.Flush();
   
      ns.Close();
      client.Close();    
   }
}
class Employee
{
   public int ID;
   private int LastNameSize;
   public string LastName;
   private int FirstNameSize;
   public string FirstName;
   public int YearsService;
   public double Salary;
   public int size;
   public Employee()
   {
   }
   public Employee(byte[] data)
   {
      int place = 0;
      ID = BitConverter.ToInt32(data, place);
      place += 4;
      LastNameSize = BitConverter.ToInt32(data, place);
      place += 4;
      LastName = Encoding.ASCII.GetString(data, place, LastNameSize);
      place = place + LastNameSize;
      FirstNameSize = BitConverter.ToInt32(data, place);
      place += 4;
      FirstName = Encoding.ASCII.GetString(data, place, FirstNameSize);
      place += FirstNameSize;
      YearsService = BitConverter.ToInt32(data, place);
      place += 4;
      Salary = BitConverter.ToDouble(data, place);
   }
   public byte[] GetBytes()
   {
      byte[] data = new byte[1024];
      int place = 0;
      Buffer.BlockCopy(BitConverter.GetBytes(ID), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(BitConverter.GetBytes(LastName.Length), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(Encoding.ASCII.GetBytes(LastName), 0, data, place, LastName.Length);
      place += LastName.Length;
      Buffer.BlockCopy(BitConverter.GetBytes(FirstName.Length), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(Encoding.ASCII.GetBytes(FirstName), 0, data, place, FirstName.Length);
      place += FirstName.Length;
      Buffer.BlockCopy(BitConverter.GetBytes(YearsService), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(BitConverter.GetBytes(Salary), 0, data, place, 8);
      place += 8;
      size = place;
      return data;
   }
   public void Display(){
      Console.WriteLine("ID = {0}", ID);
      Console.WriteLine("LastName = {0}", LastName);
      Console.WriteLine("FirstName = {0}", FirstName);
      Console.WriteLine("YearsService = {0}", YearsService);
      Console.WriteLine("Salary = {0}\n", Salary);
   }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class EmployeeSrvr
{
   public static void Main()
   {
      byte[] data = new byte[1024];
      TcpListener server = new TcpListener(9050);
      server.Start();
      TcpClient client = server.AcceptTcpClient();
      NetworkStream ns = client.GetStream();
      byte[] size = new byte[2];
      int recv = ns.Read(size, 0, 2);
      int packsize = BitConverter.ToInt16(size, 0);
      recv = ns.Read(data, 0, packsize);
      Employee emp1 = new Employee(data);
      emp1.Display();
 
      size = new byte[2];
      recv = ns.Read(size, 0, 2);
      packsize = BitConverter.ToInt16(size, 0);
      data = new byte[packsize];
      recv = ns.Read(data, 0, packsize);
      Employee emp2 = new Employee(data);
      emp2.Display();
      ns.Close();
      client.Close();
      server.Stop();
   }
}
class Employee
{
   public int ID;
   private int LastNameSize;
   public string LastName;
   private int FirstNameSize;
   public string FirstName;
   public int YearsService;
   public double Salary;
   public int size;
   public Employee()
   {
   }
   public Employee(byte[] data)
   {
      int place = 0;
      ID = BitConverter.ToInt32(data, place);
      place += 4;
      LastNameSize = BitConverter.ToInt32(data, place);
      place += 4;
      LastName = Encoding.ASCII.GetString(data, place, LastNameSize);
      place = place + LastNameSize;
      FirstNameSize = BitConverter.ToInt32(data, place);
      place += 4;
      FirstName = Encoding.ASCII.GetString(data, place, FirstNameSize);
      place += FirstNameSize;
      YearsService = BitConverter.ToInt32(data, place);
      place += 4;
      Salary = BitConverter.ToDouble(data, place);
   }
   public byte[] GetBytes()
   {
      byte[] data = new byte[1024];
      int place = 0;
      Buffer.BlockCopy(BitConverter.GetBytes(ID), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(BitConverter.GetBytes(LastName.Length), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(Encoding.ASCII.GetBytes(LastName), 0, data, place, LastName.Length);
      place += LastName.Length;
      Buffer.BlockCopy(BitConverter.GetBytes(FirstName.Length), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(Encoding.ASCII.GetBytes(FirstName), 0, data, place, FirstName.Length);
      place += FirstName.Length;
      Buffer.BlockCopy(BitConverter.GetBytes(YearsService), 0, data, place, 4);
      place += 4;
      Buffer.BlockCopy(BitConverter.GetBytes(Salary), 0, data, place, 8);
      place += 8;
      size = place;
      return data;
   }
   public void Display(){
      Console.WriteLine("ID = {0}", ID);
      Console.WriteLine("LastName = {0}", LastName);
      Console.WriteLine("FirstName = {0}", FirstName);
      Console.WriteLine("YearsService = {0}", YearsService);
      Console.WriteLine("Salary = {0}\n", Salary);
   }
}