std::ranges::transform_view<V,F>::iterator

template< bool Const > class /*iterator*/		(since C++20)

The return type of transform_view::begin, and of transform_view::end when the underlying view is a common_range.

The type /*iterator*/<true> is returned by the const-qualified overloads. The type /*iterator*/<false> is returned by the non-const-qualified overloads.

The name of this class template (shown here as iterator) is unspecified.

Typical implementation holds two data members: an iterator into (possibly const-qualified) V, and a pointer to parent transform_view.

Member types

Member type	Definition
Parent (private)	const ranges::transform_view<V, F> if Const is true, otherwise ranges::transform_view<V, F>. The name is for exposition only.
Base (private)	const V if Const is true, otherwise V. The name is for exposition only.
iterator_concept	std::random_access_iterator_tag if Base models random_access_range, std::bidirectional_iterator_tag if Base models bidirectional_range, std::forward_iterator_tag if Base models forward_range, std::input_iterator_tag otherwise.
iterator_category	Not defined if Base does not model forward_range. Otherwise, if std::invoke_result_t<F&, ranges::range_reference_t<Base>> is not an lvalue reference, std::input_iterator_tag. Else, let C be std::iterator_traits<ranges::iterator_t<Base>>::iterator_category. If C is std::contiguous_iterator_tag, the type is std::random_access_iterator_tag; otherwise, the type is C.
value_type	std::remove_cvref_t<std::invoke_result_t<F&, ranges::range_reference_t<Base>>>
difference_type	ranges::range_difference_t<Base>

Member functions

(constructor) (C++20)	constructs an iterator (public member function)
base (C++20)	returns the underlying iterator (public member function)
operator* (C++20)	accesses the transformed element (public member function)
operator[] (C++20)	accesses an element by index (public member function)
operator++operator++(int)operator--operator--(int)operator+=operator-= (C++20)	advances or decrements the underlying iterator (public member function)

Non-member functions

operator==operator<operator>operator<=operator>=operator<=> (C++20)	compares the underlying iterators (function)
operator+operator- (C++20)	performs iterator arithmetic (function)
iter_move (C++20)	obtains an rvalue reference to the transformed element (function)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
P2259R1	C++20	member iterator_category is always defined	defined only if Base models forward_range
LWG 3555	C++20	the definition of iterator_concept ignores const	made to consider