left of '.i' must have class/struct/union?

[MarketAnarchist]

Why does the following code not work? I know its a problem with scope i just dont know how to fix it.

This complication arose in a much more complected program that i was working on so i made a new simpler program solely for the purpose of demonstrating the problem that I'm having.

#include <iostream>

class COne
{
public:
	void f() {
		std::cout << qTwo.i;
	}
};

class CTwo
{
public:
	CTwo() {
		i=1;
	}
	int i;
};

COne qOne;
CTwo qTwo;

int main() {
	qOne.f();
	system("pause");
}

im going to bed now so ill check the replies in the morning. you wonderful people always come through so ill go ahead and say thanks in advance!

[N36fSL3A]

Try this.

#include <iostream>

class COne;
class CTwo;

class COne
{
public:
	void f(CTwo qTwo) ;
};

class CTwo
{
public:
        CTwo();
	int i;
};

CTwo::CTwo() {
	i=1;
}

void COne::f(CTwo qTwo) {
	std::cout << qTwo.i;
}

CTwo qTwo;
COne qOne;

int main() {
	qOne.f(qTwo);
	system("pause");
}

You're trying to access an object that's not even defined.

(Tell me if this doesn't work, I'm very tired right now)

[Thumper]

Line 7, qTwo is not in that scope, so the object doesn't exist there. The compiler doesn't know what qTwo.i is.
qTwo is instantiated later in the code.

[Duthomhas]

The only way to do it is to separate the method bodies from the class definitions/type/whatever.

class QOne;
class QTwo;

class QOne
{
Void f( QTwo qTwo );
}

Class QTwo
{
...
}

Void QOne::f( QTwo qTwo )
{
Cout << qTwo.i;
}

If QOne is going to access private stuff in QTwo, you'll have to declare it a friend, too.

Hope this helps.

[Stewbond]

Here's another way that may help. Define CTwo and qTwo before COne.

#include <iostream>

class CTwo
{
public:
	CTwo() {
		i=1;
	}
	int i;
}qTwo;

class COne
{
public:
	void f() {
		std::cout << qTwo.i;
	}
}qOne;

int main() {
	qOne.f();
	system("pause");
}

[Duthomhas]

Hmm.. yes, of course. For some reason I was thinking that the classes were mutually referential.

[MarketAnarchist]

wow thanks stewbond thats neat instantiating your classes like that. i would have never thought of that in a million years.