Re: reading string from a text file from vc++ without MFC support

On Fri, 15 Jun 2007 22:28:32 -0700, rindam2...@yahoo.com wrote:


The previous code is not good.

You are using _T and Unicode (_wfopen) in a wrong way.
_wfopen is the Unicode version of fopen, its prototype is:

 FILE*_wfopen(
    const wchar_t *filename,
    const wchar_t *mode
 );

So 'mode' is a Unicodestring(wchar_t *) in _wfopen, so you should
use L"w+", not _T("w+"), with _wfopen.

Or, if you want to use Unicode-aware style consistently, you can
write:

  // Assume 'lstr' is a TCHAR-string(e.g. a CString)
 FILE* fp = _tfopen( lstr, _T("w+") );

Your original code would compile only in Unicode builds, but is
inconsistent with TCHAR convention.

Moreover, the fwrite line does not very much make sense:


You are writing 'strTitleCurrentData' characters, but you are giving
fwrite the length of 'strTitle'... are these variables the *same*string? If so, why are you using two different variables for the samestring? The code is confusing...

Moreover, if 'strTitleCurrentDate' is of type CString, I would prefer
to explicitly cast to LPCTSTR to accessstringcharacter pointer.

Finally, are you aware that you are writing only thestringcharacters
but *no* the final _T('\0') of thestring? In fact, GetLength returns
the number of TCHARs in thestring, excluding the terminating
_T('\0').


'strTitle1' is initialized to an emptystringby the default
constructor. So 'strTitle1.GetLength()' is 0, so you are passing 0 to
GetBuffer.
Is that what you really want??


You have the same Unicode/_T (_wfopen/_T("a+")) mismatch as above.


You called GetBuffer above, but you didn't release the buffer with
ReleaseBuffer.
Moreover, where is the 'newBuffer' memory?
Where is defined that 'newBuffer' is 100 bytes?
Why are you using 'char' and not 'TCHAR'?

IMHO, the code has several inconsistent things...
You should really clean it up.

You might consider using more modern C++ I/O stream classes to manage
files; they are easier than CFILE*, are more robust (e.g. the
destructor will close thefile, while with CFILE* you may forget to
call fclose, etc.)

If you want to write to afile, you may use code as follow:

  // Yourfileobject
  std::ofstreamfile( "TheFileName.txt" );

  // You may check result withfile.is_open()
  // if (file.is_open() ...

  // Write tofile:
 file<< "This is the first line.\n";
 file<< "Hello...\n";
  ... and so on

  // You may callfile.close() or let the
  // class destructor close thefilewhen
  // 'file' variable goes out of scope.

If you want to read from afile, line by line:

  std::stringline;
  std::ifstreamfile("Data.txt");
  // if (!file.is_open()) --> error

  // Linereadingloop
  while ( !file.feof() )
  {
    std::getline(file, line );
    std::cout << "Line read: " << line << std::endl;
  }

  //file.close() or delegate to destructor

There is also the MFC CStdioFile class, but I would prefer a
substitute from CodeProject (or Tom's much better version):

http://www.codeproject.com/file/stdiofileex.asp

MrAsm