C / C++ / MFC Discussion Boards

Christian Graus1-Oct-01 13:51

1-Oct-01 13:51

Do you have any books to help you, like textbooks ? This is a *very* basic question, do you have any ideas at all ? You really should start by writing some code and posting it so that we can provide some help for you to learn, as opposed to writing a very basic C++ program that you can hand in, and you'll be back here when your next assignment is due.

Clue 1: Look up cin and cout.
Clue 2: Look up switch or if/else ( which is how switch is implimented )
Clue 3: Look up rand/srand

That's all you need actually. Feel free to post your code, or snippets of it you have trouble with, and both myself and others will be glad to point you in the right direction.

Christian

As I learn the innermost secrets of the around me, they reward me in many ways to keep quiet.

Men with pierced ears are better prepared for marriage. They've experienced pain and bought Jewellery.

OnTimer(UINT nIDEvent)

RobJones1-Oct-01 12:01

RobJones

1-Oct-01 12:01

Hello,
I have a dialog type app and I have 2 timers on the app, one timer displays the current time, and the other is a count down timer.. The problem I am having is that the count down timer is not very accurate.. it looses a few seconds every 10 minutes.. Is there another function other than OnTimer() that I can use that is exact? If so can someone provide me with a little code so I have a idea on how to use it..

Here is a small sample of the OnTimer function I am using.. I doubt there is anything wrong with it...

void CTimerDlg::OnTimer(UINT nIDEvent) 
{
	//Which timer triggered this event?
	switch (nIDEvent)
	{
		//The Current Time?
	case IDC_STATIC_TIMER1:
		//Display the current time
		m_timer1.DisplayCurrentTime();
		break;
		//The Count Down Timer?
	case IDC_STATIC_TIMER2:
		//decrement the count
		iS --;
		//format and display the count
		m_timer2.Display(iS,iM,iH,iD,(CString)m_strTimer2="%D:%H:%M:%S");
		break;
	}
	CBitmapDialog::OnTimer(nIDEvent);

Thanks,
Rob

Re: OnTimer(UINT nIDEvent)

Paolo Messina1-Oct-01 12:23

Paolo Messina

1-Oct-01 12:23

I don't know about its accuracy... but you may use GetTickCount().
Take the initial value, then use subsequent calls to have a relative time (in milliseconds).
Otherwise use the same method with CTime::GetCurrentTime() and CTimeSpan.

HTH,
Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

Re: OnTimer(UINT nIDEvent)

Nemanja Trifunovic1-Oct-01 12:24

Nemanja Trifunovic

1-Oct-01 12:24

OnTimer is not very accurate. If you want higher precision, use the multimedia timer (look at the MSDN for details). Actually, the best timer I know of is the queue timer, but this one works only with Win2k and up.

I vote pro drink Beer | [beer]

Re: OnTimer(UINT nIDEvent)

RobJones1-Oct-01 12:52

RobJones

1-Oct-01 12:52

Thank you both for your postings.. I have looked up Multimedia Timer at MSDN and it looks like is the way to go.. I'm pretty new at programing, do you have any small samples of how to implement the code? If not, no big deal, I'll try to plug away at the examples Microsoft gives (some of the stuff looks greek to me) Smile | :)

Thanks again for your input!

Rob

video into C++/MFC

john john mackey1-Oct-01 10:08

john john mackey

1-Oct-01 10:08

If I have a video clip of unknown length (file size) and in either AVI, MP3, or some other format, what would be the best way to display and control these clips from a C++ application?

One idea I have is embedding an HTML control so that I can use a resident viewer (MS MediaPlayer, RealPlayer, QuickTime, ...) from an HTML control page. Does anyone know how to embed an HTML page into VC++ applications/dialogs? (If I go this route.)

Thanks.
Johnny

Re: video into C++/MFC

Christian Graus1-Oct-01 10:47

Christian Graus

1-Oct-01 10:47

Directshow. If you #include <dshow.h> and link to Strmiids.lib Strmbasd.lib for debug and Strmiids.lib Strmbase.lib for release, you can play a video like this:

HRESULT hr;

IGraphBuilder *pGraph;
IMediaControl *pMediaControl;
IMediaEvent *pEvent;
IMediaSeeking * pSeek;
IVideoWindow * pWindow;

// Create the filter graph manager and query for interfaces.
CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER,
IID_IGraphBuilder, (void **)&pGraph);
pGraph->QueryInterface(IID_IMediaControl, (void **)&pMediaControl);
pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent);
pGraph->QueryInterface(IID_IMediaSeeking, (void **)&pSeek);
pGraph->QueryInterface(IID_IVideoWindow, (void **)&pWindow);

pGraph->RenderFile((bstr_t)lpszMovie, NULL);

pMediaControl->Run();

Christian

As I learn the innermost secrets of the around me, they reward me in many ways to keep quiet.

Men with pierced ears are better prepared for marriage. They've experienced pain and bought Jewellery.

Re: video into C++/MFC

2-Nov-01 2:56

You have to open this file with any hexadecimal or binary editor and see to the first lines. Its an "euristic" method... If you know format you can link to your application need library (winmm, qtmlclient ...)

Smile | :)

Best regards,
Oleg

Random numbers

1-Oct-01 9:23

hi , my problem is the following :

i need to generate random float values from -3.5 to +3.5
but the build in rand() function has only support for integers.

any piece of code would be fine, thanks a lot, andreas

Re: Random numbers

Mike Nordell1-Oct-01 9:38

Mike Nordell

1-Oct-01 9:38

Look up RAND_MAX. Do the math yourself (i.e. -RANDMAX/7.0-3.5). If that doesn't give you enough randmomness (in MSVC you only get 1/32k) perhaps some rand48 implementation?

Re: Random numbers

1-Oct-01 9:59

it doesnt have to be very exact....

thanks for your answer

I ve run out of ideas

1-Oct-01 9:12

Hey guys

I have just about run out of ideasi have this piece of code below which is ment to copy one buffer to another.

void CMiscFunctions::CopyValueToBuffer(BYTE *pDataToCopy, BYTE *pBuffer, DWORD *dwLengthOfBuffer, DWORD dwSizeOfData)
{
DWORD i = *dwLengthOfBuffer;
DWORD y;

char sTest[10];
_ultoa(*dwLengthOfBuffer ,sTest, 10);
AfxMessageBox(sTest);

char sTest2[10];
_ultoa(i ,sTest2, 10);
AfxMessageBox(sTest2);

for(y = 0; y < dwSizeOfData; y++, i++)
{
pBuffer[i] = pDataToCopy[y];

if(y == 0x00000ED85)
{
AfxMessageBox("full");
break;
}

}

*dwLengthOfBuffer = i;

}

But it won't copy anything bigger then 59kb. I posted this before but didn't explain it very well basically it copies from pDataToCopy to pBuffer. i is the position to start copying data to in the pBuffer and y is 0 just to increment through the pDataToCopy buffer. I also put in an if statment to see what the largest value is before it crashes which is 0x00000ED85 in hex or 60805. Which seems like a very odd number to crash on to me.

Anyway all help is appreciated peter.

Re: I ve run out of ideas

Mike Nordell1-Oct-01 9:46

Mike Nordell

1-Oct-01 9:46

Are you using Win16? In that case you must use "huge" pointers.

Else, make sure that 1) The dest buffer can hold at least dwSizeOfData+(*dwLengthOfBuffer) bytes, 2) don't release this code. Smile | :)

I'd recommend you to look up e.g. memcpy.

Re: I ve run out of ideas

Joaquín M López Muñoz1-Oct-01 9:51

Joaquín M López Muñoz

1-Oct-01 9:51

At first sight there's nothing wrong with your code, objectionable as it is. You might want to check if you reserve space enough at pBuffer to copy past the boundary of 59 KB. Why don't you try something like

int main(void)
{
  BYTE pDataToCopy [128*1024], pBuffer[128*1024]; //128 KB each
  DWORD dwLengthOfBuffer=0;
  DWORD dwSizeOfData=sizeof(pDataToCopy);

  CMiscFunctions::CopyValueToBuffer(
    pDataToCopy,pBuffer,
    &dwLengthOfBuffer,dwSizeOfData);
  
  return 0;
}

and see what happens?
Also, I suggest you take a look at standard functions for memory copying like memcpy and memmove which will outperform your handmade loop and take the pains of doing the job for you.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: I ve run out of ideas

1-Oct-01 12:54

Cheers Guys

The reason i haven't used memcpy and memove is that earlier on i have a function that copys DWORDS to the beginning of the buffer and memove and memcpy overite this DWORDS see this (pBuffer) has lots of data taken from different places then it is all written into a buffer.

Also the size of the buffer is set me realloc() would this be causing the problems.

Peter

SMTP Commands (Read Receipts)

Bret Faller1-Oct-01 9:03

Bret Faller

1-Oct-01 9:03

Good day,

Does anyone know how to request a read receipt through an smpt command like NOTIFY or RET or anything? I've been looking all over the internet but can't seem to find anything on it. I know how to do it programatically using MAPI and Outlook but I have an smtp wrapper class and want to use a straight code rather than using MAPI, etc. Any help is greatly appreciated.

Bret Faller
Odyssey Computing, Inc.

Re: SMTP Commands (Read Receipts)

Mike Nordell1-Oct-01 9:49

Mike Nordell

1-Oct-01 9:49

Isn't this taken care of the header field Read-Reciept-To
?

Re: SMTP Commands (Read Receipts)

Bret Faller2-Oct-01 13:11

Bret Faller

2-Oct-01 13:11

Thanks for your response. Actually it is
Disposition-Notification-To:

It took me forever to find this. I first thought it was Read-Receipt-To but it never worked.

Bret Faller
Odyssey Computing, Inc.

A question about thread programming

Chaos Lawful1-Oct-01 8:17

Chaos Lawful

1-Oct-01 8:17

Here is a class which I want to use in a multi-threaded program:
class threadclass {
public:
void A();
void B();
};

void threadclass::A()
{
B();
}

void threadclass::B()
{
}

UINT WINAPI threadproc(LPVOID lpData)
{
threadclass xx;
xx.A();
return 0;
}

I use it like this:
CWinThread *pThread=AfxBeginThread(threadproc,NULL);
Will there be some error occured? Is the class thread-safe? Confused | :confused:

Law is meaningless without chaos.
Chaos without Law is equal to destruction.
Chaos and Law create our rich and colorful world.

Re: A question about thread programming

Joaquín M López Muñoz1-Oct-01 8:26

Joaquín M López Muñoz

1-Oct-01 8:26

Aren't you missing anything in the exposition of your problem? The class is trivially thread safe, basically because it does nothing.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Bitmap question

#realJSOP1-Oct-01 8:13

#realJSOP

1-Oct-01 8:13

I have a populated BITMAPINFOHEADER struct, and I have the bits of a device-independent bitmap. How do I get the RGBQUAD info out of those two items to build a BITMAPINFO struct?

Re: Bitmap question

Mike Nordell1-Oct-01 9:52

Mike Nordell

1-Oct-01 9:52

I believe one of the many places this is explained can be found by a Google search for "rgbquad bitmapinfoheader" (to not promote codeguru after the takeover).

Re: Bitmap question

Paolo Messina1-Oct-01 12:33

Paolo Messina

1-Oct-01 12:33

If you have the DIB bits as they are stored in a .bmp file, youu may have a look at this on MSDN (about BITMAPFILEHEADER): "A BITMAPINFO or BITMAPCOREINFO structure immediately follows the BITMAPFILEHEADER structure in the DIB file. "
Otherwise, you should have the palette stored somewhere, then use that instead.
I think the palette is fixed in size when it is stored in a file (16 or 256 RGBQUAD entries), but the last entries could be unused (usually zeroes) if biClrUsed < 2^biBitCount.

Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

creating COM objects in Visual C++ to work in vbscript

David Higgins1-Oct-01 7:39

David Higgins

1-Oct-01 7:39

Hi All,
I am looking for some help/example code/links for the above. What I want to do is write some code in Visual C++ which will create an object. I then want to be able to use this object in vbscript and use it's member functions etc. I think the solution is ATL/Com but I'm not sure.

Any help on the above would be greatly appreciated.
thanks in advance,
Dave.

Re: creating COM objects in Visual C++ to work in vbscript

Andres Manggini1-Oct-01 8:09

Andres Manggini

1-Oct-01 8:09

Hi,

If want to use Visual C++ I think the best choice is ATL, if you are going to use your components from VBScript make sure to implement IDispatch. (that way you can use the components from ASP for instance)

You can find information on the MSDN (you will find tutoriales and articles), or look on www.amazon.com for books on the subject

Andres Manggini.
Buenos Aires - Argentina.

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