C / C++ / MFC

15-Sep-08 7:55

I see it now sorry Smile | :)

Yeah you are right I think. The more I say both versions, yours sounds better.

And using "was" implies past tense which seems silly.

Beer | [beer]

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: OT

CPallini15-Sep-08 7:48

15-Sep-08 7:48

And you're right [^]. Anyway it looks like 'wish' is needed in the sentence.

Anyway I'm a poor Italian man...
Big Grin | :-D

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]

steph515-Sep-08 5:58

15-Sep-08 5:58

Hi I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.
Am I missing something??

The error says "unresolved external symbol"
the call to the function is in file1.cpp where I have:

myClass::myFunction(variable1, variable2);

In myClass.h I have:

class myClass
{
static void myFunction
}

and in myClass.cpp I have the function definition:

myClass::myFunction()
{
//function definition
}

I can't call myFunction from file1.cpp

As you can tell I am a novice programmer and in desperate need of explanation Frown | :(

Mark Salsbery15-Sep-08 6:13

15-Sep-08 6:13

steph5 wrote:
I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.
Am I missing something??

Yes

That would make calling any external functions
impossible.

steph5 wrote:
I can't call myFunction from file1.cpp

The linker can't find myClass.obj.
Is myClass.cpp not part of the project?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

CPallini15-Sep-08 6:14

15-Sep-08 6:14

steph5 wrote:
I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.

That's true.

steph5 wrote:
Am I missing something??

Yes: in

steph5 wrote:
class myClass
{
static void myFunction
}

is not an ordinary (i.e. C-style) static function, is a static method (i.e is a member of the class even if you don't need an instance of the class to call it).

Smile | :)

Mark Salsbery15-Sep-08 6:22

15-Sep-08 6:22

CPallini wrote:
That's true.

Huh? I call static methods that aren't in the same
source file all the time Smile | :)

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

steph515-Sep-08 6:46

15-Sep-08 6:46

how?

Mark Salsbery15-Sep-08 6:53

15-Sep-08 6:53

////////////////////////////
// myClass.h
////////////////////////////

class myClass
{
public:
   static void StaticMethod();
};


////////////////////////////
// myClass.cpp
////////////////////////////

void <code>myClass::</code>StaticMethod()
{
}


////////////////////////////
// someother.cpp
////////////////////////////

void somefunc()
{
   myClass::StaticMethod();
}

Maybe you forgot the part in red above...

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

CPallini15-Sep-08 7:39

15-Sep-08 7:39

Actually his sentence,

steph5 wrote:
I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.

and yours

Mark Salsbery wrote:
Huh? I call static methods that aren't in the same
source file all the time

are not in conflict: standard (i.e C-like, not belonging to a class) static functions have file scope, while static methods have not such a constraint.
Smile | :)

toxcct15-Sep-08 7:42

toxcct

15-Sep-08 7:42

CPallini wrote:
while static methods

C++ (actually Bjarne Stroustrup) don't talk about methods (which is more correct to Java/C#), but talks about member variables and member functions.

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CPallini15-Sep-08 7:51

15-Sep-08 7:51

OOP talks about methods. C++ use its own jargon to name the same entity.
Smile | :)

Mark Salsbery15-Sep-08 7:51

15-Sep-08 7:51

I stand corrected! Smile | :)

And I'm not the one that voted you down!

Cheers!

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

CPallini15-Sep-08 7:55

15-Sep-08 7:55

Mark Salsbery wrote:
I stand corrected!

did you ever doubt if? Poke tongue | ;-P

Mark Salsbery wrote:
And I'm not the one that voted you down!

No doubt about.

BTW: no Kanine Crunchies for my troll this evening.
Smile | :)

Mark Salsbery15-Sep-08 8:03

15-Sep-08 8:03

CPallini wrote:
Kanine Crunchies

Now I'm hungry! Big Grin | :-D

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

steph515-Sep-08 6:31

15-Sep-08 6:31

Any ideas how I can have a function I can call from anywhere
but where I don't need an instance of the class to call it?

Mark Salsbery15-Sep-08 6:44

15-Sep-08 6:44

You can call a static method of a class from other cpp files!

You need to link the files however.

The problem is in your project - the linker isn't finding
the file with the function being called. Fix that and it
will work.

The two files in your example ARE in the same project, right?

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

steph515-Sep-08 6:54

15-Sep-08 6:54

yes all the files are incluceded in the same project.

how do I make sure the linker finds the file?

The thing is I can call myClass::myFunction() from one of the .cpp files in the project,
but I can't call it from another .cpp file in the same project. whats going on?

Thanks for your time

Image Processing Question

Rajesh R Subramanian17-Sep-08 23:00

Rajesh R Subramanian

17-Sep-08 23:00

Why the low vote? Someone had a bad day. Perhaps. here[^] as well.

Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche

.·´¯`·->Rajesh<-·´¯`·.
[Microsoft MVP - Visual C++]

sherinsabry15-Sep-08 4:29

15-Sep-08 4:29

Does anyone have a code that can read an image and transform the pixels to a 2d array. in C++?

I know this is something really common, but i can not find that code anywhere.

Thanks alot

Saurabh.Garg15-Sep-08 5:10

Saurabh.Garg

15-Sep-08 5:10

You can try CxImage[^].

-Saurabh

sherinsabry22-Sep-08 7:21

Image Processing Question

22-Sep-08 7:21

Thanks for your reply..

Can CxImage be used on the windows mobile 6 platform?

sherinsabry15-Sep-08 4:29

15-Sep-08 4:29

Does anyone have a code that can read an image and transform the pixels to a 2d array?

I know this is something really common, but i can not find that code anywhere.

Thanks alot

Mark Salsbery15-Sep-08 5:44

15-Sep-08 5:44

I'm not going to write the code for you, but you could easily
use the CImage class to load the image.

Once the image is loaded, CImage::GetBits(), CImage::GetPitch(),
CImage::GetWidth(), CImage::GetHeight() can be used to copy the pixel
data to an array.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

sherinsabry22-Sep-08 7:22

22-Sep-08 7:22

Thanks..

Can CxImage be used on the windows mobile 6 platform?

Mark Salsbery22-Sep-08 7:28