error C2228: left of '.Format' must have class/struct/union type求大手。

#include "stdafx.h"
#include "pingjunshu.h"
#include "pingjunshu1.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// pingjunshu1 dialog

pingjunshu1::pingjunshu1(CWnd* pParent )
: CDialog(pingjunshu1::IDD, pParent)
{
//{{AFX_DATA_INIT(pingjunshu1)
m_s1 = 0;
m_s2 = 0;
m_s3 = 0;
m_SAVER = _T("");
//}}AFX_DATA_INIT
}

void pingjunshu1::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(pingjunshu1)
DDX_Text(pDX, IDC_RICHEDIT1, m_s1);
DDX_Text(pDX, IDC_RICHEDIT2, m_s2);
DDX_Text(pDX, IDC_RICHEDIT3, m_s3);
DDX_Text(pDX, IDC_RICHEDIT4, m_SAVER);
DDV_MaxChars(pDX, m_SAVER, 100);
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(pingjunshu1, CDialog)
//{{AFX_MSG_MAP(pingjunshu1)
ON_BN_CLICKED(IDC_BUTTON1, OnButton1)
ON_BN_CLICKED(IDC_BUTTON2, Oncancel)
ON_WM_PAINT()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// pingjunshu1 message handlers
BOOL pingjunshu1::OnInitDialog()
{
CDialog::OnInitDialog();

// TODO: Add extra initialization here
double m_Sav,m_S1,m_S2,m_S3;
m_Sav=0.00;
m_S1=m_S2=m_S3;
UpdateData(FALSE);
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}
void pingjunshu1::OnButton1()
{
// TODO: Add your control notification handler code here
UpdateData();
double m_Sav,m_S1,m_S2,m_S3;
double ave=(double)(m_S1+m_S2+m_S3)/3.0;
m_Sav.Format("%6.2d",ave);
UpdateData(FALSE);
}
void pingjunshu1::Oncancel()
{
// TODO: Add your control notification handler code here

}
void pingjunshu1::OnPaint()
{
CPaintDC dc(this); // device context for painting

// TODO: Add your message handler code here

// Do not call CDialog::OnPaint() for painting messages
}

给力哈

double m_Sav

定义错了,m_Sav需要定义为CString，否则
m_Sav.Format("%6.2d",ave);
会出错
不过从你前面有
DDX_Text(pDX, IDC_RICHEDIT4, m_SAVER);
这个来看，貌似你应该写为：
m_SAVER.Format("%6.2d",ave);