C / C++ / MFC

Re: Functor help ( STL problem)

11-Oct-01 14:19

I have a struct that looks like this:

struct ViewportPos
{
	RECT rcPos;
	long Index;
};

I have a list of these in my class, and I am trying to sort them so that they sort first by the left element in the RECT, then by the top. I've got to the point of trying to specify my own function for sorting ( i.e. at this point I've not done the trivial bit of comparing two RECTs ).

inline bool RectSort(ViewportPos vpi1, ViewportPos vpi2)
{
	RECT rc1 = vpi1.rcPos;
	RECT rc2 = vpi2.rcPos;

	return FALSE;
}

then in my function below this:

std::stable_sort(m_Viewports.begin(), m_Viewports.end(), RectSort);

I get a bajillion template errors relating to basic_string, like this:

C:\My Code\VBScene\VBWindow.cpp(860) : warning C4101: 'rc1' : unreferenced local variable
C:\My Code\VBScene\VBWindow.cpp(861) : warning C4101: 'rc2' : unreferenced local variable
C:\Microsoft Visual Studio\VC98\INCLUDE\algorithm(629) : error C2784: 'class std::basic_string<_E,_Tr,_A> __cdecl std::operator +(const class std::basic_string<_E,_Tr,_A> &,const _E)' : could not deduce template argument for 'const class std::basic_
string<_E,_Tr,_A> &' from 'class std::list<struct viewportpos,class="" std::allocator<struct="" viewportpos=""> >::iterator'
C:\Microsoft Visual Studio\VC98\INCLUDE\algorithm(620) : see reference to function template instantiation 'void __cdecl std::_Insertion_sort_1(class std::list<struct viewportpos,class="" std::allocator<struct="" viewportpos=""> >::iterator,class std:
:list<struct viewportpos,class="" std::allocator<struct="" viewportpos=""> >::iterator,bool (__cdecl *)(struct ViewportPos,struct ViewportPos),struct ViewportPos *)' being compiled &tc

and then this at the bottom

C:\Microsoft Visual Studio\VC98\INCLUDE\algorithm(620) : see reference to function template instantiation 'void __cdecl std::_Insertion_sort_1(class std::list<struct viewportpos,class="" std::allocator<struct="" viewportpos=""> >::iterator,class std:
:list<struct viewportpos,class="" std::allocator<struct="" viewportpos=""> >::iterator,bool (__cdecl *)(struct ViewportPos,struct ViewportPos),struct ViewportPos *)' being compiled

Am I right in thinking I cannot create a functor that accepts my own struct ? OR am I just doing something wrong ? Confused | :confused:

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.

Christian Graus11-Oct-01 14:28

11-Oct-01 14:28

From Stroustrup p 539: The standard list does not provide random access iterators, so lists should be sorted using the specific list operators (17.2.2.1)

Let's never tell anyone about this, OK ?

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.

_StreamPtr (ADO object)

Hadi Rezaee11-Oct-01 13:25

Re: _StreamPtr (ADO object)

11-Oct-01 13:25

Hi all,
Please explain to me about _StreamPtr ...
About performance, functions and ...

Thanks

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Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Rashid Thadha12-Oct-01 6:44

Rashid Thadha

12-Oct-01 6:44

depends on what you want to do with it ?

Re: _StreamPtr (ADO object)

Hadi Rezaee13-Oct-01 12:19

The pow function for integers

13-Oct-01 12:19

I wanna load and save bitmap in Access 2000 database, please help me ...

My month article: Game programming by DirectX by Lan Mader.
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Hadi Rezaie

font compatibility

Vu Nguyen11-Oct-01 13:22

Vu Nguyen

11-Oct-01 13:22

Hi all!

I made an simple application on my computer which uses "small font"; When I bring this program to a computer that uses large font, some buttons are missing. and some buttons with long caption does not display the caption correctly. Is there a way to avoid this problem.
I am thinking of choosing a font that is not true type, so it won't grow or shrink with windows, but not sure if it will work.
Can we detect windows' font size and change dynamically?

Thanks

Vu

vucsuf

Re: font compatibility

Bernhard11-Oct-01 19:49

Bernhard

11-Oct-01 19:49

this code can be used to detect the settings...

CDC ScreenDC;
ScreenDC.CreateIC(_T("DISPLAY"), NULL, NULL, NULL);
const int x = ScreenDC.GetDeviceCaps(LOGPIXELSX);
const int y = ScreenDC.GetDeviceCaps(LOGPIXELSY);

if (x == 96 && y == 96)
{
   //Small Font
}  
else if (x == 120 && y == 120)
{
   //Large Font
}  
else
{
   //Custom Font setting
}

the only real workaround for this problem is to use, depending on the small / large font setting, two different dialog templates.. YUCK...
i don't know any better solution (other than banning the LARGE fonts).. so i would be pleased if anybody knew a better workaround..

Bernhard

"The remarkable thing about my mother is that for thirty years she served us nothing but leftovers. The original meal has never been found." Calvin Trillin

Sprudling11-Oct-01 13:22

Sprudling

11-Oct-01 13:22

Is there a function like pow (for doubles) for integers?
I could of course use the pow function, but there just _must_ be some function like it for other datatypes too.

Or is the fastest way to calculate x raised to the power of y by making a loop and multiplying x with itself y times? (faster than pow?)

Sprudling

Re: The pow function for integers

Vu Nguyen11-Oct-01 14:46

Vu Nguyen

11-Oct-01 14:46

This is right out of the MSDN.

//-----------------------------
pow
template<class t="">
complex<t> pow(const complex<t>& x, int y);
template<class t="">
complex<t> pow(const complex<t>& x, const T& y);
template<class t="">
complex<t> pow(const complex<t>& x, const complex<t>& y);
template<class t="">
complex<t> pow(const T& x, const complex<t>& y);
The functions each effectively convert both operands to the return type, then return the converted x to the power y. The branch cut for x is along the negative real axis.
//------------------------------
Vu

vucsuf

Creating dynamic array ..

Hadi Rezaee11-Oct-01 12:19

11-Oct-01 12:19

Hi all,
I wanna create array of my class, with dynamic sizes ...
First, i read number from my file:

const int lLoop = getc(fp);

Now, i wanna create my array with lLoop size ...
But i got two errors about my array size !!!

MySoundTemplate *pSound[lLoop];
for(int i = 0; i < lLoop; i++)
pSound[i] = new MySoundTemplate;

How can i slove it ?
Please help me ...

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Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Nemanja Trifunovic11-Oct-01 12:39

Nemanja Trifunovic

11-Oct-01 12:39

lLoop is "not constant enough" (it is not known at compile time)

My advice is to use STL vector. It is the easiest way to handle dynamic arrays.

I vote pro drink Beer | [beer]

Christian Graus11-Oct-01 12:47

11-Oct-01 12:47

MySoundTemplate *pSound[lLoop];

That is not going to work, because you're trying to create an array of pointers, and you can't - the compiler doesn't know the value of lLoop. You wanted to do this:

MySoundTemplate * pSound = new SoundTemplate[lLoop];

Having said that, I second the other poster - you should use STL vector.

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.

Hadi Rezaee11-Oct-01 13:37

11-Oct-01 13:37

Hi Christian Wink | ;)

MySoundTemplate * pSound = new SoundTemplate[lLoop];

This code won't work ...
I must use of STL vector ...
Thanks ...

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Christian Graus11-Oct-01 13:55

11-Oct-01 13:55

MySoundTemplate * pSound = new SoundTemplate[lLoop];

This code won't work ...

Not unless SoundTemplate is derived from MySoundTemplate.

MySoundTemplate * pSound = new MySoundTemplate[lLoop];

will work if MySoundTemplate is a class this line can see.

I must use of STL vector ...

It's better anyhow. You should consider how you will use the list, list may be a better option.

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.

Hadi Rezaee11-Oct-01 14:09

11-Oct-01 14:09

Yes, yes, i know ...
My wrong was in typing ...
I mean:
MySoundTemplate * pSound = new MySoundTemplate[lLoop];

This code won't work, too.

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Christian Graus11-Oct-01 14:13

11-Oct-01 14:13

This code won't work, too.

There is no reason in the world for this not to work, maybe you should tell me what the errors are ?

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: How about CPtrList or CPtrArray?

Mike Burston11-Oct-01 13:31

Mike Burston

11-Oct-01 13:31

Just in case you missed the advice, I'd recommend STL vector (or perhaps list), unless the cost of copying a 'MySoundTemplate' objec tis very high (in which case vector can be expensive).

-----------------------
Reg : "Well, what Jesus blatantly fails to appreciate is that it's the meek who are the problem."

Masaaki Onishi11-Oct-01 15:18

Masaaki Onishi

11-Oct-01 15:18

Hello, the codegurus around the world.;)

How about CPtrList or CPtrArray?
I think that these also works. Roll eyes | :rolleyes:

Have a nice day!

-Masaaki Onishi-

Bitmaps & pixels

11-Oct-01 12:06

How to get RGB data for pixels from bitmap?
For every pixels, and write them into txt file
Not using GetPixels, only from Bitmap

Christian Graus11-Oct-01 12:21

11-Oct-01 12:21

If you mean a Bitmap (GDI+), then use GetData. The next issue of WDJ will hopefully have an article covering all this.

If you mean CBitmap, you need to create a DIBSection. If you have a bitmap already, then copy it into a DIBSection and access the data that way. If you're creating it, create a DIBSection. This site has several DIBSection wrappers, from memory. It certainly has one.

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.

11-Oct-01 13:14

I have LPBITMAPINFOHEADER structure (it's a frame from avi file),
i can save it as bmp file, but i need array of pixels only,
like this:

12 11 34 ....
32 11 22 ....
.............
22 44 44 ....

and save it as txt file

Christian Graus11-Oct-01 13:23

11-Oct-01 13:23

If it's a BITMAPINFOHEADER and not a BITMAPINFO, then you don't have a bitmap at all, just a descriptor of what dimensions one should be. Try casting to BITMAPINFO and accessing bmiColors. The first member of BITMAPINFO is BITMAPINFOHEADER, so a cast from BI to BIH will work fine where a BIH is needed.

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.