Class X carrying a pointer to an object of class X

[Bullet Pulse]

What I have is:

Code: Select all

//x.h
class X
{
public:
   static void Initialize(X *obj1, X *obj2);
private:
   static X *x1;
   static X *x2;
};

//x.cpp
#include "x.h"
X *X::x1;
X *X::x2;

void X::Initialize(X *obj1, X *obj2)
{
   x1 = obj1;
   x2 = obj2;
}

I get the following error in VC++:
1>..\x.cpp(19) : error C2065: 'x1' : undeclared identifier
1>..\x.cpp(19) : error C2065: 'x2' : undeclared identifier


EDIT:
I fixed it by putting the Initialize() function definition in the header file.
Does anyone know why this works?

[GroundUpEngine]

Shouldn't it be ->

Code: Select all

void X::Initialize(X *obj1, X *obj2)
{
   x1 = obj1;
   x2 = obj2;
}

[Falco Girgis]

What I have is:

Code: Select all

//x.h
class X
{
public:
   static void Initialize(X *obj1, X *obj2);
private:
   static X *x1;
   static X *x2;
};

//x.cpp
#include "x.h"
X *X::x1;
X *X::x2;

void Initialize(X *obj1, X *obj2)
{
   x1 = obj1;
   x2 = obj2;
}

I get the following error in VC++:
1>..\x.cpp(19) : error C2065: 'x1' : undeclared identifier
1>..\x.cpp(19) : error C2065: 'x2' : undeclared identifier


EDIT:
I fixed it by putting the Initialize() function definition in the header file.
Does anyone know why this works?

Yeah, you're not defining the function correctly in the C++ file.

You forgot the scope resolution operator on the class name. Change:

Code: Select all

void Initialize(X*, X*)

to

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void X::Initialize(X*, X*)

[Falco Girgis]

Shouldn't it be ->

Code: Select all

void X::Initialize(X *obj1, X *obj2)
{
   x1 = obj1;
   x2 = obj2;
}

YOU BASTARD!

[GroundUpEngine]

Shouldn't it be ->

Code: Select all

void X::Initialize(X *obj1, X *obj2)
{
   x1 = obj1;
   x2 = obj2;
}

YOU BASTARD!

[Bullet Pulse]

I actually meant to include that in the example, so that is not part of the error.

[RyanPridgeon]

What I have is:

Code: Select all

X *X::x1;
X *X::x2;
[/quote]

Yeah.... don't do that.

[b]Edit:[/b]
You only have to declare the variables in a class once; it's the [i]functions[/i] that can be defined outside the class definition and declared inside.
So Just remove those two lines.

[Ginto8]

What I have is:

Code: Select all

X *X::x1;
X *X::x2;

Yeah.... don't do that.

Edit:
You only have to declare the variables in a class once; it's the functions that can be defined outside the class definition and declared inside.
So Just remove those two lines.

They're static, therefore they have to be declared in a source file to be allocated... one of the annoying things about the header file method.

Anyway, I'm not sure, but there may be an issue with the fact that the declaration of the type X hasn't completed, so the compiler doesn't know what type x1 and x2 are really supposed to be. Try putting:

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class X;

before your class declaration, and see if that helps.