C / C++ / MFC

void CMy_newDoc::Serialize(CArchive& ar)
{
  //  buffer is assumed to be a CString
  if (ar.IsStoring())
  {
    //  write to stream
    ar << buffer;
  }
  else
  {
    //  read from stream
    ar >> buffer;
  }
}

//  myobject.h  example class to store a couple numbers and a string
class CMyObject : public CObject
{
protected:  // data
  int  m_nOne;
  float  m_fTwo;
  CString  m_strData;

public:
  CMyObject() : m_nOne(0), m_fTwo(0.0)  {  }

  int      GetOne(void) const  {  return m_nOne;  }
  void     SetOne(int n)  {  m_nOne = n;  }
  float    GetTwo(void) const  {  return m_fTwo;  }
  void     SetTwo(float f)  {  m_fTwo = f;  }
  LPCTSTR  GetData(void) const  {  return m_strData;  }
  void     SetData(LPCTSTR s)  {  m_strData = s;  }

  DECLARE_SERIAL(CMyObject)

  virtual void Serialize(CArchive& ar)
  {
    if (ar.IsStoring())
    {
      ar << m_nOne << m_fTwo << m_strData;
    }
    else
    {
      ar >> m_nOne >> m_fTwo >> m_strData;
    }
  }
};  //  class CMyObject

//  myobject.cpp
IMPLEMENT_SERIAL(CMyObject, CObject, VERSIONABLE_SCHEMA | 1)

//  my_newDoc.cpp
void CMy_newDoc::Serialize(CArchive& ar)
{
  //  m_oMyObj is a class member instance of CMyObject
  if (ar.IsStoring())
  {
    //  write to stream
    ar << m_oMyObj;
  }
  else
  {
    //  read from stream
    ar >> m_oMyObj;
  }
}