'operator =' function is unavailable

void CFormulaDlg::OnButtonReset()
{
    // TODO: Add your control notification handler code here
    CString strFileName=".\\formula.ini";
    m_nOvertime=GetPrivateProfileInt("Formula","Overtime",150,strFileName);
    m_nErrand=GetPrivateProfileInt("Formula","Errand",100,strFileName);
    m_nLate=GetPrivateProfileInt("Formula","Late",10,strFileName);
    m_nAbsent=GetPrivateProfileInt("Formula","Absent",50,strFileName);
    UpdateData(FALSE);
}
这个要怎么改啊