C / C++ / MFC Discussion Boards

Moak9-Jan-10 12:00

9-Jan-10 12:00

zoopp wrote:
You said that FD_WRITE is used for handling partial sends but, according to MSDN, it will also trigger after a call to connect() or accept().

MSDN can be misleading, you can use it as a reference but it's an epic fail as a tutorial! The FD_WRITE event will also be fired once a client connects. You can interpret it as a "now it is the first time to send data", but it must not be confused with e.g. FD_CONNECT which signals when a client is connected. Check MSDN[^] where it says "Here is a summary of events and conditions for each asynchronous notification message", it describes the different meanings each event may have. Here is a simplified overview of the corresponding events:

* FD_READ informs when (more) data can be received
* FD_WRITE informs when (more) data can be send
* FD_ACCEPT informs when incoming socket is waiting at listening socket, server side only
* FD_CONNECT informs when socket has been connected or attempt failed, client side only

Okay, to answer your question, I would not disable FD_WRITE before connecting and instead let the application logic decide how it handles the event (you can always ignore it when there is no data to be sent). Let me suggest two more things, have a look at Effective TCP/IP Programming: 44 Tips to Improve Your Network Programs[^] (really can recommend to buy it) and maybe join the webchat in the link below.

Hope this helps Smile | :)

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How to check if a tree is AVL tree?

Cowork8-Jan-10 22:17

Cowork

8-Jan-10 22:17

Hi Is there any algorithm to check if a binary tree
(not BST,just a binary tree with max two childs for each parent)
is AVL tree?

Regards

Re: How to check if a tree is AVL tree?

CPallini9-Jan-10 4:42

CPallini

9-Jan-10 4:42

Cannot you use the AVL tree definition, i.e. compute the balance factor(s)?
Smile | :)

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Re: How to check if a tree is AVL tree?

Cowork9-Jan-10 13:50

Cowork

9-Jan-10 13:50

Can you write some urls with code?
This information is not enough for me

Regards

Re: How to check if a tree is AVL tree?

CPallini9-Jan-10 22:50

CPallini

9-Jan-10 22:50

Cowork wrote:
Can you write some urls with code?

Nope.

Cowork wrote:
This information is not enough for me

That is a shame: the AVL definition (and some way to traverse the tree) in my opinion is enough.
Smile | :)

Re: How to check if a tree is AVL tree?

Saurabh.Garg9-Jan-10 14:30

Saurabh.Garg

9-Jan-10 14:30

Try standardavl/[^]

-Saurabh

regular expression library for win32 api c or c++

Jayapal Chandran8-Jan-10 7:55

Jayapal Chandran

8-Jan-10 7:55

Hi,
I would like to know whether there is any library for regular expression to use in c win32 api.
I am using Dev C++ IDE to develop windows programs (not applications). It is time to change to vc 6.0 for win32 api programming. anyway... even if it could be for vc 6.0 then that would also holds good. ?

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Re: regular expression library for win32 api c or c++

LunaticFringe8-Jan-10 8:57

LunaticFringe

8-Jan-10 8:57

ATL contains an implementation called CAtlRegExp. It's a little awkward to use, though. The late Paul DiLascia created an excellent wrapper called CRegex (naturally enough). It's part of PixieLib and can be found on his web site[^].

[Edit]

Update - CAtlRegExp is no longer part of the core ATL distribution, but is included in the ATL server classes package. It can be found here[^]. The regex class is in atlrx.h.
[/Edit]

L u n a t i c F r i n g e

Re: regular expression library for win32 api c or c++

Jayapal Chandran9-Jan-10 5:37

Jayapal Chandran

9-Jan-10 5:37

Thank you for the reply. I am new to this env so it would take some time to use it.

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Re: regular expression library for win32 api c or c++

LunaticFringe9-Jan-10 11:56

LunaticFringe

9-Jan-10 11:56

You should probably go with the TR1 implementation mentioned below; it'll be less likely to be deprecated.

L u n a t i c F r i n g e

Re: regular expression library for win32 api c or c++

Jayapal Chandran10-Jan-10 8:14

Jayapal Chandran

10-Jan-10 8:14

Yeah. i have to. thank you.

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Re: regular expression library for win32 api c or c++

Graham Shanks8-Jan-10 10:39

Graham Shanks

8-Jan-10 10:39

Boost[^] contains a regular expression library called Regex.

The advantage of using this is that Regex is also part of TR1[^], so that it will be part of the C++ standard in the future and will be included as part of the standard library in upcoming C++ compilers (it was include in the April 2008 Visual Studio 2008 Feature Pack and I believe that gcc 4.0 supports it as well).

Graham

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Re: regular expression library for win32 api c or c++

Nemanja Trifunovic8-Jan-10 12:07

Nemanja Trifunovic

8-Jan-10 12:07

If you are using VC++ 2008 (or even 2005 with the feature pack), you already have TR1 regex installed. Here is a small tutorial.[^]

utf8-cpp

Re: regular expression library for win32 api c or c++

Jayapal Chandran9-Jan-10 5:39

Jayapal Chandran

9-Jan-10 5:39

Thank you for all the above replies... this it totally new so it would take some time for me to ...

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Question about reading and writing to a file

amichai228-Jan-10 6:25

amichai22

8-Jan-10 6:25

I am trying to write a triple vector to a file and then read the file back into the triple vector. When I try to read the file back after its been saved the first fifty values come out correct but the rest of the values are garbage. I'd be really appreciative if someone could help me out here. Thanks a lot!

File declaration:

fstream memory_file("C:\\Users\\Amichai\\Pictures\\output.txt", ios::in | ios::out);

The write function:

void save_training_data(fstream &memory_file, vector<vector<vector<long double> > > &training_data)
 {
   int sizeI = training_data.size();
   memory_file.write((const char *)&sizeI, sizeof(int));
   for (int i=0; i < sizeI; i++)
   {
       int sizeJ = training_data[i].size();
       memory_file.write((const char *)&sizeJ, sizeof(int));
       for (int j=0; j < sizeJ; j++) 
       {
           int sizeK = training_data[i][j].size();
           memory_file.write((const char *)&sizeK, sizeof(int));
           for (int k = 0; k < sizeK; k++)
           {
               int temp;
               temp = (int)training_data[i][j][k];
               memory_file.write((const char *)&temp, sizeof(int));
           }
       }
   } 
 }

The read function:

void upload_memory(fstream &memory_file, vector<vector<vector<long double> > > &training_data)
{
     memory_file.seekg(ios::beg);
     int temp=0;
     int sizeK, sizeJ, sizeI; 
     memory_file.read((char*)&sizeI, sizeof(int));
     training_data.resize(sizeI);
     for (int i=0; i < sizeI; i++)
     {
           memory_file.read((char*)&sizeJ, sizeof(int));
           training_data[i].resize(sizeJ);           
           for (int j=0; j < sizeJ; j++)
           {
               memory_file.read((char*)&sizeK, sizeof(int));
               training_data[i][j].resize(sizeK);
               for (int k = 0; k < sizeK; k++)
               {
                    memory_file.read((char*)&temp, sizeof(int));
                    training_data[i][j][k]=temp;
               }
           }
     } 
}

Thanks again,
Amichai

Re: Question about reading and writing to a file

amichai228-Jan-10 6:28

amichai22

8-Jan-10 6:28

Just solved the problem.
The file declaration needs the ios::binary specification.

Re: Question about reading and writing to a file

Nelek8-Jan-10 6:38

Nelek

8-Jan-10 6:38

5 for self-solved and posting the solution Smile | :)

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string array

CODEPC8-Jan-10 5:08

CODEPC

8-Jan-10 5:08

Hi
I need declare a wchar_t array which should looks like:

strarray[1] = "ddgfdgd";
strarray[2] = "ddgfdgd ... sada";
...
strarray[n] = "ddgfdgd";

The "n" is variable.

wchar_t** strarray= new wchar_t[n][];

is not correct.

Any suggestion?

Re: string array

Richard MacCutchan8-Jan-10 5:28

Richard MacCutchan

8-Jan-10 5:28

You need to allocate pointers to wchar_t like so:

wchar_t** strarray = new wchar_t*[n];

I tend to use the Windows types for character pointers like so:

LPWSTR* strarray = new LPWSTR[n];

[edit]Add ref to LPWSTR[/edit]

Re: string array

Rajesh R Subramanian8-Jan-10 6:07

Rajesh R Subramanian

8-Jan-10 6:07

While Richard has answered your query, you'll be much better off using an array of std::string objects (that is - if you don't want to use something like a vector). This means no hand crafted memory allocation or management, plus no dangling pointers or other pointer related failure modes waiting to crash your application.

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Re: string array

Cedric Moonen8-Jan-10 7:35

Cedric Moonen

8-Jan-10 7:35

A std::wstring in his case Wink | ;)

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Re: string array

Rajesh R Subramanian8-Jan-10 7:51

Rajesh R Subramanian

8-Jan-10 7:51

Ah, the joys of being a nitpick. Smile | :)

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Re: string array

Cedric Moonen8-Jan-10 8:06

Cedric Moonen

8-Jan-10 8:06

Rajesh R Subramanian wrote:
Ah, the joys of being a nitpick.

Rajesh R Subramanian wrote:
OT: How's married life? Probably too early to comment?

Honnestly, there's not much differences... We were already living together for 3 years so, not much of a change.

Cédric Moonen
Software developer

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OpenGL game tutorial in C++

Re: string array

Richard MacCutchan8-Jan-10 8:59

Richard MacCutchan

8-Jan-10 8:59

Cedric Moonen wrote:
Honnestly, there's not much differences

Don't tell her that...

Re: string array

CPallini9-Jan-10 4:56

CPallini

9-Jan-10 4:56

Richard MacCutchan wrote:
Cedric Moonen wrote:
Honnestly, there's not much differences

Don't tell her that...

Ouch, I already told her! Big Grin | :-D

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