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unindentified classes

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i have 2 classes (both in the same namespace but if different headers). In the first class, i have a pointer to the second class; and in the second class, i have an object of the first class. i tried forward declaration but nothings working... How could i fix this? Here's basically what i have..:
[source lang=c++]
~~~file1.h~~
#include "file2.h"

namespace NS
{
    class first
    {
        second* m_pvar;
        ...
    };
}

~~~ file2.h~~~
#include "file1.h"

namespace NS
{
    class second
    {
        first m_var;
        ...
    };
}


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It doesn't look like you have a forward declaration to me. In file1.h you need something like:

namespace NS {
class second;
class first {
second* m_pvar;
};
}

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Guest Anonymous Poster
Because file2.h actually uses an instance of the object, the object must be actually declared before that point.
However, file1.h only uses a pointer to the instance of the object, so it only needs to know what kind of object it is, so file1.h should look like:
namespace NS
{
class second;
class first
{
second* m_pvar;
...
};
}
-Extrarius

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i took out the forwards to show the basic idea of what i had.

i can just forward a class of a DIFFERENT file like that?

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Yes, that's the point of havig a forward declaration.

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bahh.... now when i do that, it says the extern variable i have in file1 (which is an object in file2) is unidentified...

[source lang=c++]
~~~file1.h~~
#include "file2.h"

namespace NS
{
class Second;

class First
{
Second* m_pVar;
...
Function() {Global.dosomething();};
};

}

~~~ file2.h~~~
#include "file1.h"

namespace NS
{
class Second
{
First m_Var;
...
};

class Third
{
...
};
extern third Global;
}

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Now you might want to separate out the Third class into it's own header.

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woops... my mistake... it's the global is actually of class "second" (this is kinda confusing with the actual names and code i have :-p)

[source lang=c++]
~~~file1.h~~
#include "file2.h"

namespace NS
{
class Second;

class First
{
Second* m_pVar;
...
Function() {Global.dosomething();};
};

}

~~~ file2.h~~~
#include "file1.h"

namespace NS
{
class Second
{
First m_Var;
...
};

extern Second Global;
}

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[source lang=c++]
~~~Graphics.h~~
#include "Particles.h"

namespace Engine
{
class cTexture
{
...
};

class cGraphics
{
cParticleSytem PS;
};

extern cGraphics Graphics;

}

~~~ Particles.h~~~
#include "Graphics.h"

namespace Engine
{
class cTexture; // forward

class cEmitter
{
cTexture* m_pTex;
...
Function() {Graphics.DoSomething();};
};

class cParticleSystem
{
...
};
}




THAT'S how it is...

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Use the forward declaration and put the definition of cEmitter::Function() in a source file instead of the header.

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forward declare a function? what's the syntax of that?

note: of course the DoSomething function is in the class cGraphics

class cGraphics
{
cParticleSytem PS;

DoSomething();
};

forgot that too...

is that what you meant by forward declaring that function?

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OHH! i see what you mean. don't have it inline like that, just define it, then put the code in the .cpp file. i'll try that

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sweet, that fixed the Global variable thing, but i'm still having a problem with the ParticleSystem still being an undeclared identifier...

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Seems like a good time to put cParticleSystem into its own header.

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