Re: Read line from TXT file

From:

"John" <john@microsoft.discussions.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sat, 27 Dec 2008 14:01:00 +0530

Message-ID:

<uReb31$ZJHA.3548@TK2MSFTNGP05.phx.gbl>

Hi Joseph,

CString str = TEXT(" ");

****
Why a single space character? Why not _T(""). For that matter, why
initialize it at all
because all CStrings are constructed with an empty string.

if _T(""), how while( str.GetLength() > 0) will get success?

Code Snippet:
--------------

  CStdioFile oFile;
  if (!oFile.Open("C:\\a.txt", CFile::modeRead))
  {
   return;
  }

  CString str = TEXT(" "); //to get success in while

  while( str.GetLength() > 0)
  {
   oFile.ReadString(str);
   if (str.GetLength() < 0) break; // to come out from the loop
   //Do your operations on str
  }

  oFile.Close();

c:\a.txt has:
-----
1
2
3
4

Please debug it. I dint find any issues with this code.

Do you have any efficient code than this? please provide me.

Regards,
John.

"Joseph M. Newcomer" <newcomer@flounder.com> wrote in message
news:q75al496ul7r4282rd8np1mtcabe33knrk@4ax.com...

See below...
On Fri, 26 Dec 2008 19:32:23 +0530, "John"
<john@microsoft.discussions.com> wrote:

CStdioFile oFile;
if (!oFile.Open("C:\\a.txt", CFile::modeRead))
{
return;
}

CString str = TEXT(" ");

****
Why a single space character? Why not _T(""). For that matter, why
initialize it at all
because all CStrings are constructed with an empty string.

while( str.GetLength() > 0)
{
oFile.ReadString(str);

****
Wouldn't it make more sense to look at the result of ReadString, which is
a BOOL and is
FALSE if the ReadString failed because EOF was reached.
****

if (str.GetLength() < 0) break;

****
Note that a string will never have a negative length, so this test is
nonsensical.
****

//Do your operations on str
}

oFile.Close();

Try with this code. In case of Unicode, try with CStdioFileEx.

Regards,
John.

"zack" <zack@discussions.microsoft.com> wrote in message
news:84E7C740-3FE3-4E4B-B281-4F2D36E98939@microsoft.com...

Hi ,
I would like to read line from TXT file,and to initialize my application
accordinly,
my application is based on MFC based on Vista OS,
What is the best way to read TXT file and to be able to differ between
comment line (\\ in the begining) to data line, and to know the size of
the
line ?
the data sample in the TXT file is:
// Image file Path
C:\Users\user\Documents\IM\IM_DOC\Virtual
Drive\TEST__Empty_081028_64_MB_28_oct_2008 - Copy.img
// Removable media card
f:\

any help will be good ?

Joseph M. Newcomer [MVP]
email: newcomer@flounder.com
Web: http://www.flounder.com
MVP Tips: http://www.flounder.com/mvp_tips.htm