Programming desgin

[scarecr0w132]

Hello,

I have a class Document and a class Form. I want Document class to have access to form class.
These are my two approaches -

Approach 1:
Approach 1 project found here.
mainwindow.cpp

...
// Inside MainWindow init method
    Document* document = new Document();
    setCentralWidget(document->currentForm());
...

...
// Inside MainWindow init method
    Document* document = new Document();
    setCentralWidget(document->currentForm());
...

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document.cpp

...
Document::Document()
{
    form = new Form();
}
 
Form* Document::currentForm()
{
    return form;
}
...

...
Document::Document()
{
    form = new Form();
}

Form* Document::currentForm()
{
    return form;
}
...

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Approach 2:
Approach 2 project found here.
mainwindow.cpp

...
// Inside MainWindow init method
    Form* form = new Form();
    setCentralWidget(form);
    Document* document = new Document();
    document->setCurrentForm(form);
...

...
// Inside MainWindow init method
    Form* form = new Form();
    setCentralWidget(form);
    Document* document = new Document();
    document->setCurrentForm(form);
...

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document.cpp

...
void Document::setCurrentForm(Form* currentForm)
{
    form = currentForm;
}
...

...
void Document::setCurrentForm(Form* currentForm)
{
    form = currentForm;
}
...

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which design should I use?
I want to follow Qt's design patterns.

Thanks