# std::experimental::ranges::projected

From cppreference.com
< cpp‎ | experimental‎ | ranges

Defined in header `<experimental/ranges/iterator>` |  |

template < Readable I, IndirectRegularUnaryInvocable <I> Proj>

struct projected {
using value_type =
std::remove_cv_t < std::remove_reference_t <ranges::indirect_result_of_t<Proj&(I)>>>;
ranges::indirect_result_of_t<Proj&(I)> operator*() const;
};
template < WeaklyIncrementable I, class Proj>
struct difference_type< projected <I, Proj>> {
using type = ranges::difference_type_t<I>;

};

(ranges TS)

The class template `projected` bundles a `Readable` type `I` and a function `Proj` into a new `Readable` type whose `reference` type is the result of applying `Proj` to the `reference` type of `I`. It exists solely to ease constraint specification, and so its operator*() may not be actually defined.

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