STL iterators?

Fredrik Skog

Why do I get an access violation when I try to get the value of the iterator "it" in this piece of code? When I look at the iterators they have no valid pointers to the strings.

typedef vector TFileList;
typedef TFileList::iterator TFileListIt;

CStringList strlistFiles;
fsDlg.SelectFile(&strlistFiles);
int nFiles = strlistFiles.GetCount();

if (nFiles > 0)
{
	int nIndex;
	TFileList FileList(nFiles);

	CString strFileName, strNewFileName;
	POSITION pos;

	// Populate the list with the pointers to the file names.
	for (nIndex = 0; nIndex < nFiles; nIndex++)
	{
		pos = strlistFiles.FindIndex(nIndex);
		FileList.push\_back(&strlistFiles.GetAt(pos));
	}
	
	TFileListIt start, end, it;
	start = FileList.begin();
	end = FileList.end();
	for (it = start; it != end; it++)
	{
		TRACE("> %s\\n", \*\*it);   // <-- Access violation!
	}
}

Cheers, Fredrik
Sonork ID: 100.11430:PhatBoy
"Felix qui potuit rerum cognoscere causas."

Alexandru Savescu

Try *(*it)? (Just guessing :)). Best regards, Alexandru Savescu

Fredrik Skog

The problem is that my vector seems to be empty, even though I am filling it with valid pointers.:( Cheers, Fredrik
Sonork ID: 100.11430:PhatBoy
"Felix qui potuit rerum cognoscere causas."

Alexandru Savescu

Did you call size() to see if it is empty? Best regards, Alexandru Savescu

Fredrik Skog

size() returns 8, but I have added 4 pointers to the vector.:confused: I have noticed that the vector elements does not point to m_pchData of the string list elements I am using, but to some other address. _First and _Last of the vector are updated when adding to the vector. Cheers, Fredrik
Sonork ID: 100.11430:PhatBoy
"Felix qui potuit rerum cognoscere causas."

Alexandru Savescu

Try not to store pointers, store CStrings directly. There is not much of a performance differnce since the CString does not get copied, its reference is increased. Best regards, Alexandru Savescu

Fredrik Skog

Nah, didn't work either. The push_back seems broken... Cheers, Fredrik
Sonork ID: 100.11430:PhatBoy
"Felix qui potuit rerum cognoscere causas."

Alexandru Savescu

It's this line: Fredrik Skoog wrote: TFileList FileList(nFiles); This creates nFiles items initially empty and I guess NULL pointers. That's why you had 8 items, because 4 have already been created. You shoud use:

TFileList FileList;
FileList.reserve (nFiles);

reserve allocates enough space, but does not create any items. Best regards, Alexandru Savescu

Fredrik Skog

Yep, that's it. Thanks a million! I think I'll have to hit the books now :-O Cheers, Fredrik
Sonork ID: 100.11430:PhatBoy
"Felix qui potuit rerum cognoscere causas."