Friend Class

Hello everyone. I've never used friend classes before, but just today I found (a very large) use for them in a project of mine. Anyway, what im doing is this:

Code:

class test
{
public:
	int tester;
};
	


class Cblah
{
public:
	int type;
	friend test;
};

...(later on)
Cblah bob;

...(later)
if(bob.tester==1)
{
    ...
}

But when I try to compile it, it tells me that 'tester' is not a member or Cblah. Now, it isn't, but shouldn't the friend to test allow it to access 'tester'? I may be totally wrong about how friends work, so could someone tell me either what im doing wrong or set friends straight? Thanks.

Yup, I think your idea of friend classes is totally wrong.

Friend classes/functions can access the private members of a class. That's basically it. If you specify "friend class Test" in class Blah, then it means that Test can access and manipulate private, protected and public members/functions of class Blah.

Code:

class Test
{
   public:
    void CallBlahFunc(Blah& b)
    {
        b.BlahFunc(); // valid, coz it's a friend of blah
    {
}

class Blah
{
   friend class Test;
   private:
    void BlahFunc(void);
}

Test t;
Blah b;

b.BlahFunc(); // wont work, private function
t.CallBlahFunc(); // works no problem

I hope this clears it up a bit.

cheers
U.

Thanks, understand them now!

I think what you were thinking is inheritance