C / C++ / MFC Discussion Boards

KaЯl26-Dec-02 7:26

26-Dec-02 7:26

There are several solutions:

* You may add public member functions to your document to manipulate the array from the outside of the document object
* You may directly "lend" the array to other classes like this:

CSRawDataArray &CMyDocument::GetArray()<br />
{<br />
     return m_myDataArray;<br />
}

Beware that this method returns a reference on the array, i.e. the "real" object, not a copy.

void COtherClass::AddData(CMyDocument *pDoc, CSRawDataArray *pData)<br />
{<br />
     CSRawDataArray &myArray = pDoc->GetArray();<br />
<br />
     myArray.Add(pData);<br />
}

HTH,

K.

One small village of indomitable geeks still holds out against the invaders. And life is not easy for the managers legionaries who garrison the fortified camps of Microsoftum, Javum, Ceplumplum and Vebasum

Re: CArray woes

raner26-Dec-02 22:21

raner

26-Dec-02 22:21

Hi..i've tried the following but it's still not working.Do you know wat i shld do?

-------------------------------------------------------------------
typedef CArray <srawdata *,="" srawdata="" *=""> CSRawDataArray;//outside class declaration

//in doc header
CSRawDataArray m_array1;
CSRawDataArray& GetRawDataArray() const;

//in doc source file
//doing 2 things here.(1)load data into array from text file (2)define get function

void CRainAttDoc::Serialize(CArchive& ar)
{
CString strOneLine;

while(ar.ReadString(strOneLine))
{
SRawData *pData = new SRawData;
sscanf(strOneLine,"%g%g\n",pData->x,pData->y);
m_array1.Add(pData);
}
}

CSRawDataArray &CRainAttDoc::GetRawDataArray() const
{
return m_array1;
}
---------------------------------------------------------------------
This gives me the following error:
error C2440: 'return' : cannot convert from 'const class CArray<struct srawdata="" *,struct="" *="">' to 'class CArray<struct srawdata="" *,struct="" *=""> &'

When i try to change the object declaration to this:

const CSRawDataArray m_array1;

error C2440 remains and on top of that, the following message for RemoveAll() and Add()

'RemoveAll' : cannot convert 'this' pointer from 'const class CArray<struct srawdata="" *,struct="" *="">' to 'class CArray<struct srawdata="" *,struct="" *=""> &'

I was trying to declare the function const so that other classes cant alter the value as suggested by Roman Fadeyev but it just cant work.I'm pulling my hair out!..haa thks alot for your help.

Re: CArray woes

KaЯl26-Dec-02 22:36

KaЯl

26-Dec-02 22:36

I don't understand why you're using the keyword "const". Have you tried without it ?

If you want to be sure the others classes don't mess up with the array, you may declare it as protected in your document class and add public methods (to your document class), to be sure it's the only class which will manipulate directly the array.

Re: CArray woes

raner26-Dec-02 22:49

raner

26-Dec-02 22:49

oh yah you are right, i totally forgot i can declare it as protected.

yes, it can be compiled now.however when trying to open the text file after executing the program, the serialize() function fails and returns a what appear to be an assertion failure.

Re: CArray woes

KaЯl26-Dec-02 23:20

KaЯl

26-Dec-02 23:20

I suppose your Serialize method is like

void CRainAttDoc::Serialize(CArchive& ar)<br />
{<br />
CString strOneLine; <br />
<br />
while(ar.ReadString(strOneLine)) <br />
{ <br />
SRawData *pData = new SRawData;<br />
sscanf(strOneLine,"%g%g\n",pData->x,pData->y); <br />
m_array1.Add(pData); <br />
} <br />
}

First of all, you should test if you are writing or reading, using ar.IsStoring() (Serialization works both way). Also instead using a "while" statement, I would suggest you to write explicitly at the beginning of the archive the number of items to read
It would look like this

void CRainAttDoc::Serialize(CArchive& ar)<br />
{<br />
     if(ar.IsStoring()){<br />
          // writing the data<br />
          int iSize = m_array1.GetSize();<br />
          ar << iSize;<br />
          for(int i = 0; i w iSize; i++){<br />
               // write each element here in the archive<br />
               ...<br />
          }<br />
     }else{<br />
          // reading the data<br />
          m_array1.RemoveAll();<br />
<br />
          int iSize;<br />
          ar >> iSize;<br />
          m_Array1.SetSize(iSize);<br />
          for(int i = 0; i < iSize; i++){<br />
               // read one element here and add it to the array<br />
               ...<br />
          }<br />
     }<br />
}

I'm not absolutly sure of the syntax, I write it from memory Smile | :)

HTH,

K.

Re: CArray woes

raner27-Dec-02 5:06

raner

27-Dec-02 5:06

Thks alot.

To read each element and add it to the array, can i use the code below?

SRawData *pData = new SRawData;
sscanf(strOneLine,"%g%g\n",pData->x,pData->y);
m_array1.Add(pData);

Re: CArray woes

KaЯl27-Dec-02 5:13

KaЯl

27-Dec-02 5:13

Why not using directly the archive ?

When loading:

SRawData *pData = new SRawData;
ar >> pData->x;
ar >> pData->y;
m_array1.Add(pData);

When writing:

SRawData *pData = m_array1.GetAt(i);
ar << pData->x;
ar << pData->y;
HTH,

K.

Re: CArray woes

raner27-Dec-02 6:22

raner

27-Dec-02 6:22

Because i'm not familiar with CArchive and have never tried using them before Poke tongue | ;-P

..Anyway i've tried the following.I think this has the right syntax,i've checked my books.However, it returns a "Failed to open document" dialog so i wrote the try-catch exception handling.

And it turns out that SetSize()is indeed creating problem. And the "Testing" Message Box appears a number of times before "Unexpected file format" is displayed.The document i was opening is a text file with 14 rows, 2 columns of values.

if(ar.IsStoring())
{ // writing the data
int iSize = m_array1.GetSize();
ar << iSize;
for(int i = 0; i < iSize; i++)
{
SRawData *pData = m_array1.GetAt(i);
ar << pData->x;
ar << pData->y;
}

}
else
{
m_array1.RemoveAll();
int iSize=13;
ar >> iSize;
try{
m_array1.SetSize(iSize);
}
catch(CMemoryException *e)
{
AfxMessageBox("Cant set size");
e->Delete();
}

for (int i = 0; i < iSize; i++)
{
AfxMessageBox("Testing");
SRawData *pData = new SRawData;
ar >> pData->x;
ar >> pData->y;
m_array1.Add(pData);
}
}

any idea wat is wrong now?Really appreciate your patience;)

Re: CArray woes

KaЯl27-Dec-02 12:47

KaЯl

27-Dec-02 12:47

Check your mail Smile | :)

Re: CArray woes

Roman Fadeyev26-Dec-02 0:05

Roman Fadeyev

26-Dec-02 0:05

Firstly, i advise you to read at least a couple pages of any book about templates. It will help you to control a situation. As for your question, you should type:

CArray < SRawData, SRawData& > m_array1;

Notice that your function

CArray CRainAttDoc::GetRawDataArray()

will copy whole array since you return it by value, not by ref. It is better way to use

const CArray<......>  & CRainAttDoc::GetRawDataArray() const

Re: CArray woes

raner26-Dec-02 6:38

raner

26-Dec-02 6:38

Thanks for your advice but i don't really understand the following

const CArray<......> & CRainAttDoc::GetRawDataArray() const

Can you teach me more explicitly how to pass by reference?I've tried passing a reference to an array before but it didn't work out.

Once again, thank you.

Re: CArray woes

Christian Graus26-Dec-02 0:11

Christian Graus

26-Dec-02 0:11

Can I also recommend that now is a good time to learn about vector, which is part of the STL ( i.e. part of C++ instead of part of Microsofts proprietary code ), and is far better than CArray ? CArray works fine, and the advice you've been given should get it working, but you will eventually wish it did something that the STL does, so now is a good time to learn the better alternative.

Christian

No offense, but I don't really want to encourage the creation of another VB developer.
- Larry Antram 22 Oct 2002

C# will attract all comers, where VB is for IT Journalists and managers - Michael
P Butler 05-12-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not
as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

Re: CArray woes

User 665826-Dec-02 0:41

User 6658

26-Dec-02 0:41

I'd also like to learn STL with all its useful classes, but I don't know where to start, since STL is quite complex and has many functions like vector, list etc. Can you suggest me some good tutorials on STL apart from the ones here at cp.com?

thanks in advance
Greg

modified 12-Sep-18 21:01pm.

Re: CArray woes

Christian Graus26-Dec-02 0:47

Christian Graus

26-Dec-02 0:47

The ones here are easier ( I hope so, I wrote some of them ), but the definitive reference is www.sgi.com/tech/stl ( from memory, if it's wrong go to www.sgi.com and look for it ). That's where I go. Addison Wesley have several good books on STL, and I know that the main one on the standard library is available through Safari ( safari.oreilly.com ).

Have you looked at my tutorials here ? Is there any way in which they are not clear ?

Christian

No offense, but I don't really want to encourage the creation of another VB developer.
- Larry Antram 22 Oct 2002

C# will attract all comers, where VB is for IT Journalists and managers - Michael
P Butler 05-12-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not
as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

Re: CArray woes

User 665826-Dec-02 2:49

User 6658

26-Dec-02 2:49

I have read all your tutorials about STL, and they are all great Smile | :)

But I think that they cover only the basics (but they to that very well), and I'd like to go more into detail and get to know all the facets of STL. Thanks for the SGI link, seems to be exactly what I was looking for Smile | :)

best regards
Greg

modified 12-Sep-18 21:01pm.

Re: CArray woes

Christian Graus26-Dec-02 10:12

Christian Graus

26-Dec-02 10:12

I see - I thought you were saying the opposite, that you needed something easier to understand. Yes, the SGI site is an excellent place to take it further.

Christian

No offense, but I don't really want to encourage the creation of another VB developer.
- Larry Antram 22 Oct 2002

C# will attract all comers, where VB is for IT Journalists and managers - Michael
P Butler 05-12-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not
as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

MMC tutorial required

FASTian25-Dec-02 22:48

FASTian

25-Dec-02 22:48

i need a beginners tutorial on MMC. Does any one have a step by step guide or a tutorial. Any help regarding this would be appreciated

editing a menu

citroen25-Dec-02 22:46

citroen

25-Dec-02 22:46

I am trying to edit a menu I created.
For some reason when I compile and run the program, the old menu appears. How do I solve this problem?

Moshe

Adding WTL controls to MFC projects

Hockey25-Dec-02 21:39

Hockey

25-Dec-02 21:39

Is this possible? I've had such dismal success in the past and I would really like to do so with the following code:

http://www.codeproject.com/wtl/TabbingFramework.asp#xx345002xx

Any help appreciated!

Thanks! Smile | :)

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

LZH decompression?

Dov Sherman25-Dec-02 20:00

Dov Sherman

25-Dec-02 20:00

I apologize if this is inappropriate for this forum but I don't know where else to ask...

I'm working on an application which makes use of data stored in LZH archive files. I tried using Micco's UNLHA32.DLL but it pops out a Kernel32 access violation every time it extracts a file. LHA.DLL will only extract files to disk; I need to extract them to memory.

I can code my own handler for LZH header data but extracting the compressed data is beyond my abilities. Does anyone know of a good LZH library for C++ (to be used in VC++6) which can be used to extract files to memory?

Re: LZH decompression?

Mike Nordell26-Dec-02 6:29

Mike Nordell

26-Dec-02 6:29

Try Googling for LZH (or LHA). The source is freely available for (the original) LHA.

ActiveX control

chepuri_uk25-Dec-02 19:59

chepuri_uk

25-Dec-02 19:59

Drawing on the ActiveX Control in design-mode, is this possible ? i.e After placing the ActiveX control on a DialogBox, i want to draw on the Control.

Thank you

WSARecv and IOCP :: Winsock

valikac25-Dec-02 19:34

valikac

25-Dec-02 19:34

Hi.

I am working on a network client and one of its features is download files over HTTP server, i.e. www.abc-xyz.com/files.exe. The program downloads some files successfully, but it fails to download some files. For some reason, it download the all files, but some files are unvalid in terms of CRC.

I understand that the server initially sends information about a file including its size and type (Content-Type). However, for some reason files that have bad CRC seem to miss the beginning chunk of data. In other words, the program does the file, but the first twenty bytes might contain bad CRC. Here is the algorithm of the design.

- Send request (GET)
- Call WSARecv
- On first incoming data, analyze data and determine file size.
- Analyze data and save any valid data that server might have including with file information.
- Call WSARecv
- Continue calling WSARecv and appending new data until size of data equals the size that the server sent.

I would like to know is it possible that the server sends out the data before it sends out information about the data such as size? With the algorithm above, the program can download some file, but fails other files in terms of CRC. I cannot understand how that is possible because the size of the file is correct most of the time, but even so the files have bad CRC. Another interesting fact is that the bad CRC always occurs at the beginning such as the first 20 bytes.

Thanks,
Kuphryn

Re: WSARecv and IOCP :: Winsock

RobJones26-Dec-02 5:20

RobJones

26-Dec-02 5:20

Have you taken a look at this http://www.codeproject.com/internet/winsockintro02.asp

Seems like this is what you're doing..

Re: WSARecv and IOCP :: Winsock

valikac26-Dec-02 6:44

valikac

26-Dec-02 6:44

Okay. Thanks.

Conceptually, yes, Nishant S discussed a Winsock program I am working on. However, in reality my algorithm and his algorithm are completely different.

I understand his algorithm.

Kuphryn

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