Re: class in class
Seungbeom Kim <musiphil@bawi.org> wrote:
You can create the mapping explicitly:
struct A
{
struct C
{
C(A& a) : parent_(a) { }
A& parent_;
} c;
A() : c(*this) { }
};
Now the C object contains a reference to an A object (supposedly the one
that contains it), and the A object initializes its c sub-object by
giving it the reference to itself.
A couple of small thoughts:
Using a pointer keeps A copyable and assignable without change if it
was originally. It also keeps A::C copyable and assignable if it was.
Further if conversion from A::C to A can safely be done implicitly.
[It appears so] then operator A &() const; is a one liner. Const
because the conversion does not modify A::C. Then getting reference
from the object c, is simply
A::C t = ...;
A &a = t;
or even
void foo(A &a);
foo(t); as long as foo is not a templated function.
class A::C
{
A *parent_;
public:
C (const A &a):parent_(&a){}
operator A & () const {return *parent_;}
// ...
};
comes to mind. [looks a lot like a reference wrapper like provided by
boost and tr1].
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