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Re: swap two values withou using temp. storage

Member 322138523-Jul-10 7:16

23-Jul-10 7:16

<joke>

to avoid using temporary storage - i would consider showing the user two boxes, and asking them to swap the numbers for me. this is safe for strings or XML or whatever. if the user chooses to use Notepad or something, it doesn't bother me, but i know that my code executes as fast as possible and is bug-free because i am using natural techniques from nature.

microsoft does this when you have to change your password. it shows you three text boxes. the first is your old password, and the next two are your new password. the code first checks that the new password matches the new new password, and then swaps the new new password for the old password.

works seamless every time

Re: swap two values withou using temp. storage

Kenneth Kasajian23-Jul-10 14:40

Kenneth Kasajian

23-Jul-10 14:40

x^=y;
y^=x;
x^=y;

Yes, it's cute, but it's faster to use a temporary. The xor method is only useful if you're doing it in assembly language and you don't have a free register or a temporary memory location.

ken@kasajian.com / www.kasajian.com

Re: swap two values withou using temp. storage

manjulameganathan23-Jul-10 18:00

manjulameganathan

23-Jul-10 18:00

int x=150;
int y=45;

x=x+y;(195)
y=x-y;(150)
x=x-y;(45)

Re: swap two values withou using temp. storage

Jigar Sheth25-Jul-10 20:38

Jigar Sheth

25-Jul-10 20:38

x = 15
y =13

x=x + y (15 + 13) = 28
y = x- y (28-13) = 15

x = x-y(28-15)
x = 13

Hence x=13;
y=15.

jigar sheth

WaveInOpen Help??

AmbiguousName21-Jul-10 19:36

AmbiguousName

21-Jul-10 19:36

hello guys.....im new to this. I wanna know that how can I get started with waveInOpen?? I am getting confused. What is the right path to get used to it. I just can not be happy taking samples from Internet, I must learn it but not taking it on the big picture, what is the right place.......plz plz help me.

Re: WaveInOpen Help??

«_Superman_»21-Jul-10 19:38

«_Superman_»

21-Jul-10 19:38

I believe this is the first thing to read - waveInOpen Function[^]

«_Superman_»

I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

How can disable a subitem where i use COutlook2Ctrl::OCL_SELECT?

Le@rner21-Jul-10 19:23

Le@rner

21-Jul-10 19:23

Hi,

i m taking help of this article for design outlook style

Outlookbar-style menu interface[^]

i m using COutlook2Ctrl::OCL_SELECT for trigger with assign Menu Item,in menu item this is disable by CCmdUI,

but please tell me how can i disable this purticular subitem in this outlook tree.

please help me for this.

thanks in advance.

how Does CWinApp realize the singleton pattern?

zxjun8421-Jul-10 18:54

zxjun84

21-Jul-10 18:54

Generally,singleton pattern is applied by the way that the ctor is private and gives a member funtion named getInstance, but CWinApp's instance is defined as a global object,its ctor is not private.So how MFC realizes the singleton pattern for CWinApp?

Re: how Does CWinApp realize the singleton pattern?

«_Superman_»21-Jul-10 19:45

«_Superman_»

21-Jul-10 19:45

The CWinApp class is not a singleton class.
It doesn't need to be because MFC needs this class has to be created before it internally calls WinMain.

If it was designed as a singleton, you would be able to create it only after WinMain in called and also you would need to write WinMain yourself.

That is why you create a global instance of it and you must create only one as the documentation says.
This is as easy as saying that you can only have one main or WinMain function.

«_Superman_»

I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: how Does CWinApp realize the singleton pattern?

zxjun8421-Jul-10 20:39

zxjun84

21-Jul-10 20:39

I Made a test .If i instance another global CWinApp descendant class.In release mode ,there is only one instance in the application ,but not two.How does MFC keep only one CWinApp descendant instance in the application?

Re: how Does CWinApp realize the singleton pattern?

«_Superman_»21-Jul-10 21:26

«_Superman_»

21-Jul-10 21:26

This works in Release mode because the ASSERT macro has no effect in Release mode.
MFC maintains several global functions whose begin with Afx and several global variables whose names begin with _afx.
These are the variables that are used to invoke the various methods in the code.
These variables will be overwritten by the second instance of CWinApp.
So only the last instance of CWinApp will be the valid object.
All the rest will simply occupy space in memory.

«_Superman_»

I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: how Does CWinApp realize the singleton pattern?

zxjun8421-Jul-10 22:18

zxjun84

21-Jul-10 22:18

wonderful!I got it ,thank you!

problem between OS of 32bit ans 64 bits

xjh_sz21-Jul-10 15:03

xjh_sz

21-Jul-10 15:03

I recently created a driver installation program, which uses a number of core functions such as UpdateDriverforPlugAndDevice(), using vs2008, in 32-bit operating system everything is working properly. But win32 program can run in x64, but under x64 it does not work. For example UpdateDriverForPlugandPlayDevices() raises an error, I used GetLastError (), and I see an error code. Later I was using a 64-bit system with vs2008 and compiled the x64 program, everything works fine, but the program can not run in win32. The problem is now solved, but I now maintain two versions of the installer 32 and 64; I do not know what a better way, I just run a seperate version of the executable.

Re: problem between OS of 32bit ans 64 bits

«_Superman_»21-Jul-10 19:53

«_Superman_»

21-Jul-10 19:53

When 32-bit apps try to access certain folders or registry keys in a 64-bit environment, they will be redirected to another path.

For example, drivers are normally copied to C:\Windows\System32\drivers.
When a 32-bit app tries to copy a driver to this location, it will redirected to C:\Windows\SysWOW64\drivers.

This is probably what is going on in you case and so you will have to maintain 2 separate versions of your installer program.

«_Superman_»

I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Crash Window on Close [modified]

Fareed Rizkalla21-Jul-10 14:10

Fareed Rizkalla

21-Jul-10 14:10

I get a crash on a Windows Message!
Looked it up in WinUser.h and didn't find anything for it.

This is the MSG number 274.

As it appears when I press close on my Window, my program is receiving a WM_SYSCOMMAND.
This is totally a new thing, I already have a WM_CLOSE.
Can't understand what is triggering it.

modified on Wednesday, July 21, 2010 9:04 PM

Re: Crash Window on Close

«_Superman_»21-Jul-10 20:00

«_Superman_»

21-Jul-10 20:00

WM_CLOSE is not the last message that an application will receive.
This is normal.
But why is that causing a crash for you?
Perhaps, you could debug after it crashes.

«_Superman_»

I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: Crash Window on Close

ThatsAlok22-Jul-10 0:35

ThatsAlok

22-Jul-10 0:35

kindly let us know,Is crash is appearing in Debug Mode or release mode!

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture

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Memory Leak

Fareed Rizkalla21-Jul-10 13:36

Fareed Rizkalla

21-Jul-10 13:36

I ran code analysis on my project.
It told me I had a memory leak.

I have a Linked List class with an Add function.
The Add function receives parameters, then it creates a node and fills it with those parameters.
I can't understand why their is a leak!

Re: Memory Leak

Maximilien21-Jul-10 13:54

Maximilien

21-Jul-10 13:54

ok, but how do you remove items from the list ? is it done automatically by the list class destructor ?

Watched code never compiles.

Re: Memory Leak

Fareed Rizkalla21-Jul-10 14:08

Fareed Rizkalla

21-Jul-10 14:08

list class destructor!

Re: Memory Leak

Aescleal21-Jul-10 22:14

Aescleal

21-Jul-10 22:14

This may sound like a daft couple of questions...

- Are you sure the memory leak is in your class? Try swapping it for one that you know doesn't leak like std::list and run your analysis again.

- Why on earth are you writing your own linked list? std::list will probably do as good a job in most cases.

Ash

Re: Memory Leak

David Crow22-Jul-10 3:03

David Crow

22-Jul-10 3:03

Aescleal wrote:
- Why on earth are you writing your own linked list?

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CTabCtrl color background Problem [modified]

etipaq21-Jul-10 5:50

etipaq

21-Jul-10 5:50

Hi all,

I have a problem to set correctly the color background of a CTabCtrl under Windows XP. IT work great under Vista/Seven. But XP still not working after many try.

So you can see 2 print screen (one in Vista and one in XP) you will see that the one on XP don't paint correctly the background windows (right beside the last tab).

http://www.devntic.com/IMAGES/PrintSreenVista.jpg[^]

http://www.devntic.com/IMAGES/printscreenXP.JPG[^]

this is my code to do what you see in these print screen..

I have a Class to manage CTabCtrl --> in this case COnglet (it's Tab in french)

BOOL COnglet::OnEraseBkgnd(CDC* pDC)
{
	//(HDC)wParam3
	RECT rect;
	this->GetWindowRect(&rect);
	::FillRect(pDC->GetSafeHdc(), &rect, static_cast<HBRUSH>(((CDlg_Modele*)m_TabOnglet[0]->ptrEcran)->m_DlgBGColor));

	return FALSE; // don't do the default erase
}

void COnglet::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{	
	CRect rect = lpDrawItemStruct->rcItem;
	rect.top += ::GetSystemMetrics(SM_CYEDGE);
....
...

	pDC->SetBkMode(TRANSPARENT);
	pDC->FillSolidRect(rect, ((CDlg_Modele*)m_TabOnglet[0]->ptrEcran)->m_bgColor);
	
...
...

	pDC->RestoreDC(nSavedDC);
}

Thanks in advance for any help you could provide to me

regard Etienne

PS: sorry, my english is not perfect.

modified on Wednesday, July 21, 2010 3:18 PM

Re: CTabCtrl color background Problem

Niklas L21-Jul-10 10:12

Niklas L

21-Jul-10 10:12

I gave the class an English sounding name, et voilà

BOOL CMyTabCtrl::OnEraseBkgnd(CDC* pDC)
{
	//(HDC)wParam3
	RECT rect;
	this->GetWindowRect(&rect);

	//----------------
	ScreenToClient(&rect); // (And added this)
	//----------------

	::FillRect(pDC->GetSafeHdc(), &rect, static_cast<HBRUSH>(((CDlg_Modele*)m_TabOnglet[0]->ptrEcran)->m_DlgBGColor));

	return FALSE; // don't do the default erase
}

I strongly suggest that you give identifiers English names, unless a customer demands another language in a contract. And even then, try to convince him before accepting.

A simple thing as asking for help might reduce your chances of getting a good response. But there are better reasons, working with developers from different countries being one. Going public with parts of your code being another. I once had an interface file for a complex system completely in Dutch in my hands. Oh my oh my...

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Re: CTabCtrl color background Problem

Code-o-mat21-Jul-10 10:34

Code-o-mat

21-Jul-10 10:34

Was it Dutch, Dutch++ or maybe Dutch#? Big Grin | :-D

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> "It doesn't work, fix it" does not qualify as a bug report. <
> Amazing what new features none of the programmers working on the project ever heard of you can learn about when reading what the marketing guys wrote about it. <

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