Constructor child_iterator<I>() (1) (defaulted) explicit child_iterator<I>(I x) (2) template <class U> child_iterator<I>(const child_iterator<U> & u) (3) (1) child_iterator<I>() (defaulted) Default ctor (2) explicit child_iterator<I>(I x) Iterator ctor Parameters I x (3) template <class U> child_iterator<I>(const child_iterator<U> & u) Rebase ctor Parameters const child_iterator<U> & u