C / C++ / MFC

Re: cpuh header is not supported by my compiler .. What should i do to make it support.?

22-Jan-09 7:19

Sure!

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

led mike22-Jan-09 8:37

led mike

22-Jan-09 8:37

Code-o-mat wrote:
Maybe it stands for

CodeProject User Help me pleeeezzzzz it's urgent

led mike

Re: cpuh header is not supported by my compiler .. What should i do to make it support.?

Code-o-mat22-Jan-09 8:40

Code-o-mat

22-Jan-09 8:40

You will have to give us more details, we do not have enough information to be able to help you.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Re: cpuh header is not supported by my compiler .. What should i do to make it support.?

ssivus23-Jan-09 20:01

ssivus

23-Jan-09 20:01

any way thanks for all your funny replies ...

Regards

$iva

Discrete Derivative with arrays?

LostPitch22-Jan-09 5:34

LostPitch

22-Jan-09 5:34

Hello,
this is quite a newbie question but I would appreciate a lot your help..
Let's suppose I want to implement an algorithm that behaves like the matlab "diff" command, that is given an input array of size N [x(1)......x(n)] it returns an array of N-1 elements [x(2)-x(1) .... x(n) - x(n-1)], like a sort of discrete derivative.
I would like to avoid to use vectors but simply arrays. The problem is I don't know how to create the second array of size N - 1. I could compute the size a priori and pass it as a parameter, but if I write

float* OUTarr = diff(float* INarr)
int size = sizeof(INarr)/sizeof(float);
float OUTarr[size];

two problems arise: first the size is always one (not depending on the real size of INarr) and second there's a compiler error 'expected a constant size'.
The same appears if I pass the size as a parameter of the function.
I know that allocation for arrays is static and actually I can't know the size of the array at compile time, but I could always know the exact size of the array before its allocation, so I shouldn't require the use of dynamic memory...
Thank you in advance for any suggestion!

L.

CPallini22-Jan-09 6:05

22-Jan-09 6:05

Your code has another problem: if you build the array inside the function, as local storage, you cannot return it.
If you're stuck with the above (IMHO bad) design, you may try with a template function, for instance

#include <stdio.h>

float alfa[10]={0,1,2,3,4,5,6,7,8,9};

template <int N>
float *  diff(float a[N])
{
	static float b[N-1];

	for (int i=0; i<N-1; i++)
	{
		b[i] = a[i+1]- a[i];
	}


  return b;
}



void main()
{
	float * beta = diff<10>(alfa);

	for (int i=0; i<9; i++)
	{
		printf("beta[%d]=%f\n", i, beta[i]);
	}
}

Please note: the static allocation of b is just a workaround, there are better ways to do it (for instance, the caller may provide storage for b).
Moreover, personally, I prefer dynamic memory allocation for such a task.
Smile | :)

Stuart Dootson22-Jan-09 12:37

22-Jan-09 12:37

LostPitch wrote:
I know that allocation for arrays is static

Only when they're allocated on the stack.

What's wrong with allocating the array on the heap:

float* diff(float* inArr, size_t inArrSize)
{
   float* outArr = new float[inArrSize-1];
   for(size_t i=0;i<inarrsize-1;++i)>
   {
      outArr[i] = inArr[i+1]-inArr[i];
   }
   return outArr;
}

Yes, you need to deallocate it after it's been used with delete[], but hey - it works!

Also - what's with the use of float? Doubles have more bits and are also faster, as floating point hardware is double or bigger internally and has performance penalties for converting to and from single precision floating point data.

LostPitch wrote:
I would like to avoid to use vectors

Again - why? vectors (certainly after the TR1 update to the C++ standard) are guaranteed to be as efficient as arrays. They also do all the memory management for you. What's not to like?

CPallini22-Jan-09 21:06

22-Jan-09 21:06

Stuart Dootson wrote:
What's wrong with allocating the array on the heap

That you should at least check for the allocation result. Poke tongue | ;-P

Stuart Dootson22-Jan-09 22:57

22-Jan-09 22:57

Why? I use a modern C++ system that throws when new fails Poke tongue | ;-P

OMG!

CPallini22-Jan-09 23:25

22-Jan-09 23:25

OMG another ot those terrible over-the-top-youngster-developers!!!!!
Big Grin | :-D

Re: OMG!

Stuart Dootson22-Jan-09 23:34

22-Jan-09 23:34

CPallini wrote:
youngster

I wish...

I first programmed in C on my ZX Spectrum[^] around 1984. Can you imagine compiling in C (think headers...) when your only storage is a tape deck?

Re: OMG!

SandipG 23-Jan-09 0:14

SandipG

23-Jan-09 0:14

Stuart Dootson wrote:
I first programmed in C on my ZX Spectrum[^] around 1984.

That time i was only few months old Frown | :(

BTW: THHB in action Smile | :)

Regards,
Sandip.

Re: OMG!

CPallini23-Jan-09 0:36

23-Jan-09 0:36

Stuart Dootson wrote:
I first programmed in C on my ZX Spectrum[^] around 1984.

I did the same. Smile | :)

Stuart Dootson wrote:
Can you imagine compiling in C (think headers...) when your only storage is a tape deck?

C? I started with BASIC Roll eyes | :rolleyes:

, but soon passed to Z80 assembly!
Big Grin | :-D

BTW: as told in advance by the (I would say 'good-old' but he's really youngster...) SandipG, welcome in the THHB [^], [^]!

How to create DialogBox at runtime without adding it into the Resource.rc?

LostPitch24-Jan-09 1:31

LostPitch

24-Jan-09 1:31

Thanks Pallini and Stuart,
For the first solution I already knew the static trick but not the template one Smile | :)

For the second..actually I had already used it developing a vst long time ago but I forgot Smile | :)

I used the float since in vst 2.4 the processReplacing function manages float data and it's mandatory to implement it..anyway in the end I followed your advise and used vectors!
Thanks again!!

Abhijit D. Babar22-Jan-09 4:22

Abhijit D. Babar

22-Jan-09 4:22

Hello all,

I am new to MFC. I know how to create dialogbox by adding the new resource into the resource file. But i want to create DialogBox at runtime without adding it into the Resource.rc file. After creating dialogbox, i have to add Edit control, List Box over that dialog box.

How can i do this?

Thanks in advance.

Re: How to create DialogBox at runtime without adding it into the Resource.rc?

Sarath C22-Jan-09 4:31

Sarath C

22-Jan-09 4:31

Check this[^]

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

Re: How to create DialogBox at runtime without adding it into the Resource.rc?

Iain Clarke, Warrior Programmer22-Jan-09 5:19

Iain Clarke, Warrior Programmer

22-Jan-09 5:19

I would also recommend reading this post:
http://blogs.msdn.com/oldnewthing/archive/2005/04/29/412577.aspx[^]
and some previous ones.

Heck, I recommend reading every single one of his blog posts - you'll learn about lots of things you should and should not be doing.

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Re: How to create DialogBox at runtime without adding it into the Resource.rc?

Abhijit D. Babar22-Jan-09 22:15

Abhijit D. Babar

22-Jan-09 22:15

Thanks for ur reply and suggesting me the link.

I read this post, but it is hard to understand for me, because i am new to MFC.
Please suggest the simplest way with example for creating dialog box without adding dialog resource into the resource.rc file.

Re: How to create DialogBox at runtime without adding it into the Resource.rc?

Iain Clarke, Warrior Programmer22-Jan-09 22:36

Iain Clarke, Warrior Programmer

22-Jan-09 22:36

Abhijit D. Babar wrote:
because i am new to MFC

This is allllll windows stuff - MFC hardly comes in at all.

Abhijit D. Babar wrote:
Please suggest the simplest way

There is no simple way - that's one of the reasons we use templates.

Abhijit D. Babar wrote:
with example

Read a few months of the blog before the article I point you at - he builds up from very small examples to large complex ones. I could not write a better one - especially here on the fly.

Good luck,

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Re: How to create DialogBox at runtime without adding it into the Resource.rc?

Abhijit D. Babar23-Jan-09 0:53

Abhijit D. Babar

23-Jan-09 0:53

thank u sir

convert System::String to char *

bubuzzz22-Jan-09 3:00

bubuzzz

22-Jan-09 3:00

hi all,

I am trying to convert from System::String to char *. After searching some forums and the msdn, i got these lines of code

const char * convertStrToChar(System::String ^ str)
{
CString tmpStr (str);
char* ConvToChar = new char[tmpStr.GetLength() + 2];
size_t Converted = 0;
wcstombs_s(&Converted, ConvToChar, tmpStr.GetLength()+1, tmpStr, _TRUNCATE);

return ConvToChar;

}

However, when i compilie it, these error messages appear :

Error 1 error LNK2028: unresolved token (0A00023F) "public: char * __clrcall Process::convertStrToChar(class System::String ^)" (?convertStrToChar@Process@@$$FQAMPADP$AAVString@System@@@Z) referenced in function "public: void __clrcall Process::showFaceDetect(class System::String ^,class System::String ^)" (?showFaceDetect@Process@@$$FQAMXP$AAVString@System@@0@Z) Process.obj

Error 2 error LNK2019: unresolved external symbol "public: char * __clrcall Process::convertStrToChar(class System::String ^)" (?convertStrToChar@Process@@$$FQAMPADP$AAVString@System@@@Z) referenced in function "public: void __clrcall Process::showFaceDetect(class System::String ^,class System::String ^)" (?showFaceDetect@Process@@$$FQAMXP$AAVString@System@@0@Z) Process.obj

I know this is a simple problem, but i cannot figure out why this bug happens. Can you give me some suggestion? Thanks

Re: convert System::String to char *

Stuart Dootson22-Jan-09 3:37