#pragma once

// Modify the following defines if you have to target a platform prior to the ones specified below.
// Refer to MSDN for the latest info on corresponding values for different platforms.
#ifndef WINVER // Allow use of features specific to Windows XP or later.
#define WINVER 0x0501 // Change this to the appropriate value to target other versions of Windows.
#endif
#ifndef _WIN32_WINNT // Allow use of features specific to Windows XP or later. 
#define _WIN32_WINNT 0x0501 // Change this to the appropriate value to target other versions of Windows.
#endif 
#ifndef _WIN32_WINDOWS // Allow use of features specific to Windows 98 or later.
#define _WIN32_WINDOWS 0x0410 // Change this to the appropriate value to target Windows Me or later.
#endif
#ifndef _WIN32_IE // Allow use of features specific to IE 6.0 or later.
#define _WIN32_IE 0x0600 // Change this to the appropriate value to target other versions of IE.
#endif
#define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers
// Windows Header Files:
#include <windows.h>
// C RunTime Header Files
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>
#include <tchar.h>

My abc.h file contain:

#include <afxwin.h>
#include <stdio.h>
#include <winsock2.h>
#include <conio.h> 
#include <iostream>
using namespace std;

class CIPMessage
{
public:
CIPMessage();
~CIPMessage();
void Init(string sIpAddress, int iPort);
int SendMessagePort(string sMessage);
int RecMessagePort();
bool IsConnected(){return m_bIsConnected;}
private:
bool m_bIsConnected; // true - connected false - not connected
string m_sServerIPAddress;
int m_iServerPort;
SOCKET conn; // socket connected to server
};