CODEWITHSUNDEEP
c++classiterator
ginevracoal
ginevracoal

Reputation: 103

ConstIterator from Iterator definition

In a tree template class, a ConstIterator is being defined from an Iterator in the following way:

template <typename k_T, typename v_T>
class Tree<k_T, v_T>::ConstIterator : public Tree<k_T, v_T>::Iterator {
  using parent = Tree<k_T, v_T>::Iterator;

 public:
  using parent::Iterator;
  const std::pair<k_T, v_T>& operator*() const { return parent::operator*(); }
};

but it's not clear to me what the using parent::Iterator is doing.

Upvotes: 0

Views: 33

Answers (1)

erenon
erenon

Reputation: 19118

It inherits the constructors of parent.

If the using-declaration refers to a constructor of a direct base of the class being defined (e.g. using Base::Base;), constructors of that base class are inherited [...] The inherited constructors are equivalent to user-defined constructors with an empty body and with a member initializer list consisting of a single nested-name-specifier, which forwards all of its arguments to the base class constructor.

See Inheriting constructors: http://en.cppreference.com/w/cpp/language/using_declaration

Upvotes: 1

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