C / C++ / MFC Discussion Boards

Jörgen Sigvardsson10-May-05 1:46

10-May-05 1:46

I'd like to stress PJ's point that you should *always* use delete [] with new []. Otherwise strange things will happen. Trust me. Smile | :)

--
Schni Schna Schnappi! Schnappi Schnappi Schnapp!

Re: about "delete"

Nemanja Trifunovic10-May-05 3:58

Nemanja Trifunovic

10-May-05 3:58

I'd suggest he (almost) never uses new[] and delete[] and make use of container classes instead. Here is why[^]

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

Re: about "delete"

hfrmobile12-May-05 21:05

hfrmobile

12-May-05 21:05

I allways used delete regardless if used new or new[]

...it worked fine (and I see no reason why it should not...)

<br />
byte buffer[4] = new byte[4]; // 4 bytes<br />
DWORD dw4Bytes = new DWORD[1]; // 4 bytes<br />
<br />
...<br />
<br />
delete buffer;  // releases 4 bytes<br />
delete dw4Bytes; // releases 4 bytes<br />

Re: about "delete"

Nemanja Trifunovic13-May-05 3:56

Nemanja Trifunovic

13-May-05 3:56

rubicon_hfr wrote:
...it worked fine (and I see no reason why it should not...)

Because for one thing, your example is not exception-safe. If in the "..." code an exception is thrown, you'll end up with a memory leak.

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

Re: about "delete"

hfrmobile16-May-05 20:35

hfrmobile

16-May-05 20:35

Because for one thing, your example is not exception-safe. If in the "..." code an exception is thrown, you'll end up with a memory leak.

Since the topic has the subject "about delete" I only mention that there is no difference between delete and delete[].

You may assume that "..." stands for the following:

<br />
try<br />
{<br />
  // do something meaningful<br />
}<br />
catch (...)<br />
{<br />
}<br />

Of course you can use finally to free memory... Rose | [Rose]

Or you just use a wrapper class which ctor does this for you (so you can't forget)...

Or use managed C++ Laugh | :laugh:

just finished my 2d game engine

tom_dx9-May-05 14:56

tom_dx

9-May-05 14:56

at least to an extent were its working Smile | :)

took me 30min - 1hr to write it, had 1 bug but fixed it with debugging in under 3 sec. flat!!! Smile | :)

so exciting but I came across a wierd error, when i just used "D3DXVECTOR3(x, y, 0)" in one of the location parameters in the ID3DXSPRITE interface, Draw() to be exact, it wouldn't accept it, but then i tried "&D3DXVECTOR3(x, y, 0)" and it worked, what am i misunderstanding here, D3DXVECTOR3 is type struct by the way D'Oh! | :doh:

IM PROUD TO BE A GMAIL;

Re: just finished my 2d game engine

Christian Graus9-May-05 15:22

Christian Graus

9-May-05 15:22

tom_dx wrote:
but then i tried "&D3DXVECTOR3(x, y, 0)" and it worked, what am i misunderstanding here, D3DXVECTOR3 is type struct by the way

Simple, a struct is completely different to a pointer.

tom_dx wrote:
IM PROUD TO BE A GMAIL;

So was I, until my mail started to disappear.

Christian Graus - Microsoft MVP - C++

Re: just finished my 2d game engine

tom_dx10-May-05 12:20

tom_dx

10-May-05 12:20

whoops

have to break out my C++ reference Smile | :)

IM PROUD TO BE A GMAIL;

Looking for calendar control

David Crow9-May-05 10:20

David Crow

9-May-05 10:20

I need something like Microsoft MonthView Control v6.0 (from mscomct2.ocx) but with the ability to select non-contiguous dates, too.

Thank you,
DC

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: Looking for calendar control

Ravi Bhavnani9-May-05 10:46

Ravi Bhavnani

9-May-05 10:46

Like this[^]?

/ravi

My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com

Re: Looking for calendar control

David Crow10-May-05 2:11

David Crow

10-May-05 2:11

Thanks. It's hard to tell without a sample executable to play around with. Do you know if the dates can be navigated with the arrow keys on the keyboard?

- DC

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: Looking for calendar control

Ravi Bhavnani10-May-05 2:13

Ravi Bhavnani

10-May-05 2:13

Sorry David, I don't know.

/ravi

My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com

Print menu selection

Member 19632089-May-05 9:10

Member 1963208

9-May-05 9:10

I have working with CHtmlView derived SDI application.
Want to catch Event when user select print menu . do some processing like display a message box ..and then continuing printing ..How can I do it ..is it possible with OnCmdMsg() ..if yes How Big Grin | :-D

Re: Print menu selection

ThatsAlok9-May-05 22:28

ThatsAlok

9-May-05 22:28

Look for Virtual Function [CView::OnPreparePrinting]

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Recursive file listing

__makaveli__9-May-05 4:23

__makaveli__

9-May-05 4:23

Hi,

I am having real trouble getting this to work, basically I want to create an array of file names and folder names given a starting point, for example:

Start point:
C:\

Folder list:
Windows
Windows\Config
Windows\System32
Windows\System

File list:
Windows\appversions.dll
Windows\twain_32.dll
Windows\Config\foo.txt
Windows\System32\bootvrfy.exe

What would be the best way to go about this (Without using MFC), I have tried making a recursive method using FindFirstFile and FindNextFile but don't seem to be having any luck.

Thanks in advance!

Re: Recursive file listing

David Crow9-May-05 4:57

David Crow

9-May-05 4:57

__makaveli__ wrote:
I have tried making a recursive method using FindFirstFile and FindNextFile but don't seem to be having any luck.

Show us the code that is not working.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: Recursive file listing

__makaveli__9-May-05 5:02

__makaveli__

9-May-05 5:02

void SearchFolders(LPCTSTR wStart)
{
WIN32_FIND_DATA hDat;
HANDLE hFindFile;

hFindFile = FindFirstFile(wStart, &hDat);

if( hFindFile != INVALID_HANDLE_VALUE ) {
while( FindNextFile(hFindFile, &hDat) )
{
if( hDat.dwFileAttributes && FILE_ATTRIBUTE_DIRECTORY ) {
// File is a folder
SearchFolders(hDat.cFileName);
} else {
// File is a file
MessageBox(0, hDat.cFileName, "File", MB_OK);
}
}
}
}

I have deleted the code that crashes but this was my last attempt, I tried to make it as simple as possible so I could expand on it once I got it showing a messagebox for each file but I do not get one messagebox.

Re: Recursive file listing

jmkhael9-May-05 5:49

jmkhael

9-May-05 5:49

Try changing
if( hDat.dwFileAttributes && FILE_ATTRIBUTE_DIRECTORY ) {

to

if( hDat.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY ) {

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

Re: Recursive file listing

__makaveli__9-May-05 5:56

__makaveli__

9-May-05 5:56

Thanks for the suggestion but still no messageboxes

Re: Recursive file listing

jmkhael9-May-05 6:04

jmkhael

9-May-05 6:04

Dont forget the wildcards:

SearchFolders("D:\\test\\*.*");

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

Re: Recursive file listing

__makaveli__9-May-05 6:17

__makaveli__

9-May-05 6:17

I have just tried that, I am getting somewhere now, at first I got a stack of messageboxes all saying ".\*", I have now added a check for dots but it's still not recursive.

I'm now using:
void SearchFolders(LPCTSTR wStart)
{
WIN32_FIND_DATA hDat;
HANDLE hFindFile;
char DirSpec[MAX_PATH];

ZeroMemory(DirSpec, MAX_PATH);
strncpy (DirSpec, wStart, strlen(wStart+1));
strncat (DirSpec, "\\*", 3);

hFindFile = FindFirstFile(DirSpec, &hDat);

if( hFindFile != INVALID_HANDLE_VALUE ) {
while( FindNextFile(hFindFile, &hDat) )
{
if( hDat.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY ) {
// File is a folder
if( (strncmp(hDat.cFileName, ".", 1) != 0) || (strncmp(hDat.cFileName, "..", 2) != 0 ) ) {
char subDir[MAX_PATH];
strcat(subDir, hDat.cFileName);
strcat(subDir, "\\*");
SearchFolders(subDir);
}
} else {
// File is a file
MessageBox(0, hDat.cFileName, "File", MB_OK);
}
}
}
}

Re: Recursive file listing

David Crow9-May-05 6:25

David Crow

9-May-05 6:25

__makaveli__ wrote:
strncat(DirSpec, "\\*", 3);

strncat(DirSpec, "\\*.*", 4);

__makaveli__ wrote:
if( (strncmp(hDat.cFileName, ".", 1) != 0) || (strncmp(hDat.cFileName, "..", 2) != 0 ) ) {
char subDir[MAX_PATH];
strcat(subDir, hDat.cFileName);
strcat(subDir, "\\*");
SearchFolders(subDir);

The second condition is redundant (at least I've not ever seen a folder whose name began with a '.' but whose second character was not a '.'). Also, appending '*' here and at the start of the function is wrong.

if (hDat.cFileName[0] != '.')
{
    char subDir[MAX_PATH];
    strcpy(subDir, wStart);
    strcat(subDir, "\\");
    strcat(subDir, hDat.cFileName);
    SearchFolders(subDir);
}

See here and here for others' interpretation of this exercise. Here is an MFC snippet.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: Recursive file listing

Bob Stanneveld10-May-05 0:19

Bob Stanneveld

10-May-05 0:19

DavidCrow wrote:
The second condition is redundant (at least I've not ever seen a folder whose name began with a '.' but whose second character was not a '.').

I have. The last time I used the CFile class from MFC, these names came up when I search through some folders...
Also when you use the dir command in dos, you see those names for the current and previous directory!

I also got the blogging virus..[^]

Re: Recursive file listing

David Crow10-May-05 1:57

David Crow

10-May-05 1:57

Bob Stanneveld wrote:
Also when you use the dir command in dos, you see those names for the current and previous directory!

That's exactly what I said. Unless a folder was named something like ".abc" I do not see the need to check the second character if the first one was a dot. It certainly does not hurt anything to check, but I was just trying to shorten the OP's code down a bit.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: Recursive file listing

Graham Bradshaw9-May-05 6:23

Graham Bradshaw

9-May-05 6:23

__makaveli__ wrote:
SearchFolders(hDat.cFileName);

You'll need to append the previous directories to this path, and then call SearchFolders, or change your working directory before and after the call. The problem is that FindFirstFile is *always* searching the current directory.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.