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friend class problem

 
 
chandra sekhar
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Posts: n/a
 
      01-13-2004
Hi All,

I have problem regarding the friend class.
I have a library where the class are declration is follows ( only
example )

class Frame
{
public:
protected:
void printFramemsg()
{
cout << " test... " << endl;
}
private:

// by making this we can access the protected members in the view

friend class View;
};

class View
{
public:
void setFrame(Frame* aFrame)
{
myFrame = aFrame;
}
void print()
{
myFrame->printFramemsg();
}
protected:
Frame* myFrame;
};

Now I want to derive the View class and access the protected and private
members of the Frame class..

class myView : public View
{
public:
void print_1()
{
myFrame->printFramemsg();
}
private:
};

Is any workarround or other way to do this .. ( Here I do not want to
derive a class from Frame ... )

Bye
Chandra

 
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Karl Heinz Buchegger
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Posts: n/a
 
      01-13-2004
chandra sekhar wrote:
>
> class View
> {
> public:
> void setFrame(Frame* aFrame)
> {
> myFrame = aFrame;
> }
> void print()
> {
> myFrame->printFramemsg();
> }
> protected:
> Frame* myFrame;
> };
>
> Now I want to derive the View class and access the protected and private members of the Frame
> class..


Why?
The Frame class has a public interface. You ought to use that, that's why
it exists.

>
> class myView : public View
> {
> public:
> void print_1()
> {
> myFrame->printFramemsg();


myView is not a friend of the frame. But View (the base class of myView)
is. Thus:

View:rint();


--
Karl Heinz Buchegger
http://www.velocityreviews.com/forums/(E-Mail Removed)
 
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Ernst Murnleitner
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Posts: n/a
 
      01-13-2004
Dear Chandra,

There is no way for inheritance of friendship. So, you have to make the
derived class a also a friend.
With private members there is no other way.
But with protected members I don not know, as I never had to use friends.

I would derive a class MyFrame from Frame. Here you can access the protected
member of Frame. Make the function for accessing public and you need no
friends - or make it protected or private and make MyView a friend of
MyFrame.

Greetings
Ernst


 
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