Weird Problem

[hsteo]

Hi all,

#include "stdafx.h"
#include "Asimulator.h"
#include "inputBoxAP.h"
#include <cstring>
#include <fstream>

// inputBoxAP dialog

IMPLEMENT_DYNAMIC(inputBoxAP, CDialog)

inputBoxAP::inputBoxAP(CWnd* pParent /*=NULL*/)
	: CDialog(inputBoxAP::IDD, pParent)
	, amtAP(0)
{
	
}

inputBoxAP::~inputBoxAP()
{
}

void inputBoxAP::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	DDX_Text(pDX, IDC_EDIT1, amtAP);
	DDV_MinMaxInt(pDX, amtAP, 3, 5);
}


BEGIN_MESSAGE_MAP(inputBoxAP, CDialog)
	ON_EN_CHANGE(IDC_EDIT1, &inputBoxAP::OnEnChangeEdit1)
	ON_EN_UPDATE(IDC_EDIT1, &inputBoxAP::OnEnUpdateEdit1)
	ON_BN_CLICKED(IDOK, &inputBoxAP::OnBnClickedOk)
END_MESSAGE_MAP()


// inputBoxAP message handlers -- The most imprt handler is OnBnClickedOK(), the rest don't care

void inputBoxAP::OnEnChangeEdit1()
{
	// TODO:  If this is a RICHEDIT control, the control will not
	// send this notification unless you override the CDialog::OnInitDialog()
	// function and call CRichEditCtrl().SetEventMask()
	// with the ENM_CHANGE flag ORed into the mask.

	// TODO:  Add your control notification handler code here
	
}

void inputBoxAP::OnEnUpdateEdit1()
{
	// TODO:  If this is a RICHEDIT control, the control will not
	// send this notification unless you override the CDialog::OnInitDialog()
	// function to send the EM_SETEVENTMASK message to the control
	// with the ENM_UPDATE flag ORed into the lParam mask.

	// TODO:  Add your control notification handler code here
}

void inputBoxAP::OnBnClickedOk()
{
	// TODO: Add your control notification handler code here
	OnOK();
        
        ofstream inputdata; < -- ERROR HERE

	// To test if the operation is functioning correctly
	CString temp;	
	temp.Format(_T("%d"),amtAP);
	AfxMessageBox(temp);
}

Notice that at the last function, i include ofstream inputdata, but there is always an error produced:

ofstream undeclare identifier.

What is wrong here?