How to refer to class which was not yet declared?

[CrazyBoy]

This is my global class:

#include "stdafx.h"

MyGlobalClass::MyGlobalClass(int argc, char* argv[]){
	CLParser * CLPars( MyGlobalClass& );
	FILE_ * File( MyGlobalClass& );
	CLPars.ParseArgs(argc, argv);
}

The classes CLParser and file FILE_ were included before global class. I need to have access to MyGlobalClass within these two classes. But the problem is that MyGlobalClass was not declared before. How to solve this problem?

I tried to access the global class as so:

class FILE_{
public:
	void FILE_( MyGlobalClass& );
}

But MyGlobalClass is undeclared.

[2kaud]

You need to forward declare the classes required. But note that for a forward declared class you can only access the elements via pointers.

See http://stackoverflow.com/questions/9...rd-declaration
http://stackoverflow.com/questions/5...rd-declaration

Before the definiton of CLParser class, put

class MyGlobalClass;

but note the comment re access to the members of MyGlobalClass.

[CrazyBoy]

I already found it searching web. But I still have some nasty errors :-) Saying things like that I am missing ';' when I try to create new instance of MyGlobalClass and _FILE. I cannot find out where the ; could be missing. global.h:

class MyGlobalClass{
	private:		
		CLParser CLPars;
		FILE_ File;
};

Any idea why this could happen?

[CrazyBoy]

What's the problem here?

#include "stdafx.h"

FILE_::FILE_( MyGlobalClass * globInst){
	PGlobalInstance = globInst;
}

int FILE_::IsDirectory(std::string path, char * workingPath){
PGlobalInstance->readDirectoryFiles = true;
}

error C2227: left of '->readDirectoryFiles' must point to class/struct/union/generic type

How to solve this?

[2kaud]

I already found it searching web. But I still have some nasty errors :-) Saying things like that I am missing ';' when I try to create new instance of MyGlobalClass and _FILE. I cannot find out where the ; could be missing. global.h:

class MyGlobalClass{
	private:		
		CLParser CLPars;
		FILE_ File;
};

Any idea why this could happen?

Often because the compiler isn't recognising CLParser or FILE_ as a type/class. Note that if CLParser or FILE_ is forward declared you can't use it in statements like this as the class isn't fully defined at this point.

[2kaud]

What's the problem here?

#include "stdafx.h"

FILE_::FILE_( MyGlobalClass * globInst){
	PGlobalInstance = globInst;
}

int FILE_::IsDirectory(std::string path, char * workingPath){
PGlobalInstance->readDirectoryFiles = true;
}

error C2227: left of '->readDirectoryFiles' must point to class/struct/union/generic type

How to solve this?

Where is PGlobalInstance defined?

[CrazyBoy]

file.cpp

FILE_::FILE_( MyGlobalClass * globInst){
	PGlobalInstance = globInst;
}

header:

class FILE_{
private:
	MyGlobalClass * PGlobalInstance;
public:
	FILE_( MyGlobalClass * globInst );
	static int GetEncoderClsid(
			const WCHAR* format, 
		CLSID* pClsid);

	int findFiles(std::string path);
	static int IsDirectory(std::string path, char * workingPath);
};

Edit:
This looks correct:

class FILE_{
private:
	MyGlobalClass * PGlobalInstance;
public:
	FILE_( MyGlobalClass * globInst );
	static int GetEncoderClsid(
			const WCHAR* format, 
		CLSID* pClsid);

	int findFiles(std::string path);
	int IsDirectory(std::string path, char * workingPath);
};

[2kaud]

A class static member function cannot access a non-static member. If you want a static member function to access members of a class instance you will need to pass a pointer to the class instance as part of the static function parameters.

Why do you want IsDirectory to be static?

[CrazyBoy]

It should not be static. I changed design, originally it was static. But if I remove static I get this error:
clparser.cpp(22): error C2352: 'FILE_::IsDirectory' : illegal call of non-static member function

class FILE_{
private:
	MyGlobalClass * PGlobalInstance;
public:
	FILE_( MyGlobalClass * globInst );
	static int GetEncoderClsid(
			const WCHAR* format, 
		CLSID* pClsid);

	int findFiles(std::string path);
	int IsDirectory(std::string path, char * workingPath);
};

The error line:

if (FILE_::IsDirectory(arg, PGlobalInstance->workingPath)) {

Edit:
On the other hand if I use static, then I got this error:
file.cpp(113): error C2227: left of '->readDirectoryFiles' must point to class/struct/union/generic type

PGlobalInstance->readDirectoryFiles = true;

this is in

int FILE_::IsDirectory(std::string path, char * workingPath){

[2kaud]

As IsDirectory is now not static, it can only be referenced via an instance of the class and not via the class name.

Any non-static member has to be referenced via a class instance. Static members are referenced via the class name. If you need to use IsDirectory() without reference to a class instance then it needs to be static which means it cannot directly access any non-static members.

[CrazyBoy]

So I should do it like

if (PGlobalInstance->File->IsDirectory(arg, PGlobalInstance->workingPath)) { ... }

In main file I have this:

class MyGlobalClass{
public:
		std::vector<Src*> sources;
		std::vector<Target*> destination;
		
		CLParser CLPars;
		FILE_ File;

		char * workingPath;
		int actualSource;
		int actualTarget;
		bool getRegEx;
		bool readDirectoryFiles;
		static int IsDirectory(std::string path);
		MyGlobalClass(int argc, char* argv[]);
};

Edit

Yet another error:
error C2819: type 'FILE_' does not have an overloaded member 'operator ->'

[2kaud]

Please post the full code as I've lost track as to where things are defined and used.

IsDirectory is a static member of MyGlobalClass and hence can't be referenced from an instance as standard and can't reference an instance.

[CrazyBoy]

Not static anymore:
Parse3.cpp:

#include "stdafx.h"
//...

MyGlobalClass * Obj;

int main(int argc, char* argv[])
{
MyGlobalClass Obj(argc, argv);
}

[2kaud]

Please post the full code rather than links to the code. I only look at code that is actually posted here.

Not static anymore:

and is there still a compile issue?

You would probably get guidance from more members if you posted on codeguru.

[CrazyBoy]

Of sure it is. What code should I post? Here are 10 files

The error is:
error C2819: type 'FILE_' does not have an overloaded member 'operator ->'

file.cpp line 20

CLParser::CLParser(  MyGlobalClass * globInst ){
    PGlobalInstance = globInst;
	}
void CLParser::ParseArgs(int argc, char* argv[]){
...
if (PGlobalInstance->File->IsDirectory(arg, PGlobalInstance->workingPath)) {
}
}

PGlobalInstance should be pointer to global instance of MyGlobalClass. What does mean this error? I expect the operator is correct.

[CrazyBoy]

On StackOverFlow I have found one guy asking similar question:
http://stackoverflow.com/questions/1...ember-operator
I think the answer by Al Crowley should be close, however on his code I am not sure where exactly he suggest to paste this line:

List * listptr = new List();

In my case, I with to create new instance of FILE_ and CLParser in global.cpp during which the constructors should be fired. Hence I think I should not need the new keyword. I expected that copy constructor should be enough to create the instance in the scope of MyGlobalClass::MyGlobalClass(...) function.

Edit:
I got feeling that problem could be here in the function MyGlobalClass::MyGlobalClass(...):

CLParser * CLPars( MyGlobalClass );
FILE_ * File( MyGlobalClass );

I am trying to pass a class, but there should be reference to the instance of MyGlobalClass ... And the instance must be create in main file parse.cpp

[CrazyBoy]

Yet now in the MyGlobalClass::MyGlobalClass(...) function if I add a pointer to arguments of constructors:

MyGlobalClass::MyGlobalClass(int argc, char* argv[]) 
{
	CLParser * CLPars( MyGlobalClass *);
	FILE_ * File( MyGlobalClass *);
}

I got new error:
error C2512: 'CLParser' : no appropriate default constructor available
error C2512: 'FILE_' : no appropriate default constructor available

[2kaud]

FILE_::FILE_( MyGlobalClass * globInst){
	PGlobalInstance = globInst;
}

the constructor to FILE_ takes as argument a pointer to MyGlobalClass. Therefore to use the FILE_ constructor in MyGlobalClass you will need to pass a pointer to the current instance of MyGlobalClass which is the variable 'this' within MyGlobalClass class. So try

MyGlobalClass::MyGlobalClass(int argc, char* argv[]) 
{
	CLParser * CLPars(this);
	FILE_ * File(this);
}

I haven't tried this so you may need to cast this to MyGlobalClass *. The same applies to CLParser. See http://msdn.microsoft.com/en-us/library/y0dddwwd.aspx and other related articles on MSDN and stackoverflow

[CrazyBoy]

Yeah, this all I tried already and nothing worked. Same error still. Maybe I should refer to the object by reference and not by pointer?
I read this question: http://stackoverflow.com/questions/6...-c-inner-class
and they use referece, but they are also using nested classes which I don't use. I have my classes separated.

[2kaud]

If you merge your .h and .cpp files into one file that demonstrates the problem and post it here I'll have a look.

[CrazyBoy]

No need anymore. Compiled. There was initiation list needed for the main class.

[AceInfinity]

Just because the code compiled doesn't mean it is okay. From what I seen there was lots wrong with the structure of your application design. If you want to learn better ways of writing the implementation of your program, post the full code.