thank you very much. it helps me. :D

I'm running an MFC apps in Visual 2012 for Genetic Algorithm Timetable.

c:\users\zahrina\documents\visual studio 2012\projects\gaschedule\gaschedule\gaschedule.h(6): fatal error C1189: #error : "include 'stdafx.h' before including this file for PCH"
main.cpp
c:\users\zahrina\documents\visual studio 2012\projects\gaschedule\gaschedule\gaschedule.h(6): fatal error C1189: #error : "include 'stdafx.h' before including this file for PCH"
GaScheduleDoc.cpp
c:\users\zahrina\documents\visual studio 2012\projects\gaschedule\gaschedule\gaschedule.h(6): fatal error C1189: #error : "include 'stdafx.h' before including this file for PCH"
GaSchedule.cpp
c:\users\zahrina\documents\visual studio 2012\projects\gaschedule\gaschedule\gaschedule.h(6): fatal error C1189: #error : "include 'stdafx.h' before including this file for PCH"
CourseClass.cpp

Here is the coding for gaschedule.h

// GaSchedule.h : main header file for the GaSchedule application
//
#pragma once

#ifndef __AFXWIN_H__
#error "include 'stdafx.h' before including this file for PCH"
#endif

#include "resource.h" // main symbols

// CGaScheduleApp:
// See GaSchedule.cpp for the implementation of this class
//

class CGaScheduleApp : public CWinApp
{
public:
CGaScheduleApp();

// Overrides
public:
virtual BOOL InitInstance();

// Implementation

public:
afx_msg void OnAppAbout();
DECLARE_MESSAGE_MAP()
};

extern CGaScheduleApp theApp;