Re: Private Member Access failed through Friend function
On May 2, 10:42 am, Cumhur Guzel <guzelcum...@gmail.com> wrote:
I think you could get better encapsulation plus flexibility by using
the template method pattern with NVI,
namespace X {
class Base {
public:
void print(std::ostream& os) {
myprint(os);
}
private:
virtual void myprint(std::ostream&)=0;
};
class D1: Base {
private:
virtual void myprint(std::ostream&) {};
};
class D2: Base {
private:
virtual void myprint(std::ostream&) {};
};
std::ostream& operator<<(std::ostream& os, Base& b) {
b.print(os); return os;
}
(I assume the non-cost Base parameter and the private inheritance are
typos.)
And this is back to an example where I think a friend function is
preferable to a public print() function:
class Base {
private:
virtual void do_print(std::ostream&) = 0;
friend ostream& operator<<( ostream& os, Base const& b ) {
b.do_print(os); return os;
}
};
Why introduce the redundant print() function when you can do it
directly with the more idiomatic operator<< simply by making it a
friend?
--
Richard Smith
--
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By STAN GOFF
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