VC++在TXT文件指定位置追加内容的方法

void CGoToFileDlg::OnPaint()
{
 if (IsIconic())
 {
 CPaintDC dc(this); 
 SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);
 int cxIcon = GetSystemMetrics(SM_CXICON);
 int cyIcon = GetSystemMetrics(SM_CYICON);
 CRect rect;
 GetClientRect(&rect);
 int x = (rect.Width() - cxIcon + 1) / 2;
 int y = (rect.Height() - cyIcon + 1) / 2;
 dc.DrawIcon(x, y, m_hIcon);
 }
 else
 {
 CDialog::OnPaint();
 }
}
HCURSOR CGoToFileDlg::OnQueryDragIcon()
{
 return (HCURSOR) m_hIcon;
}
void CGoToFileDlg::OnButopen()
{
 CFileDialog dlg(TRUE,NULL,NULL,OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,
 "All Files(*.TXT)|*.TXT||",AfxGetMainWnd());//构造文件打开对话框
 if (dlg.DoModal() == IDOK)//判断是否按下"打开"按钮
 {
 m_Path = dlg.GetPathName(); //获得文件路径
 FILE *pFile = fopen(m_Path,"r+t");//以读写形式打开文件
 if (pFile)//判断文件是否被正确打开
 {
  char pchData[1000] = {0};//定义数据缓冲区
  fread(pchData,sizeof(char),1000,pFile); //读取数据到缓冲区中
  fclose(pFile);//关闭文件
  m_File = pchData;
 }
 UpdateData(FALSE);
 }
}
void CGoToFileDlg::OnButinsert()
{
 UpdateData();
 FILE *pFile = fopen(m_Path,"r+t");//以读写形式打开文件
 if (pFile)//判断文件是否被正确打开
 {
 fseek(pFile,m_Goto,SEEK_SET);//定位文件
 CString str = m_Text + m_File.Right(m_File.GetLength()-m_Goto);//设置字符串
 fputs(str.GetBuffer(0),pFile); //向文件中写入数据
 fseek(pFile,0,SEEK_SET);//重新定位文件
 char pchData[1000] = {0};//定义数据缓冲区
 fread(pchData,sizeof(char),1000,pFile); //读取数据到缓冲区中
 fclose(pFile);//关闭文件
 m_File = pchData;
 UpdateData(FALSE);
 }
}