std::ranges::cartesian_product_view<First, Vs...>::iterator<Const>::next, std::ranges::cartesian_product_view<First, Vs...>::iterator<Const>::prev, std::ranges::cartesian_product_view<First, Vs...>::iterator<Const>::distance_from

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Ranges library
Range adaptors
 
 

std::ranges::cartesian_product_view::iterator::next

template< std::size_t N = sizeof...(Vs) >
constexpr void /*next*/();
(since C++23)
(exposition only*)

If called with default template parameter, recursively generates the next element (the tuple of iterators) in cartesian_product_view.

Let current_ denote the underlying tuple of iterators. Equivalent to:

auto& it = std::get<N>(current_);
++it;
if constexpr (N > 0)
{
    if (it == ranges::end(std::get<N>(parent_->bases_)))
    {
        it = ranges::begin(std::get<N>(parent_->bases_));
        next<N - 1>();
    }
}

Used in the following non-static member functions:

std::ranges::cartesian_product_view::iterator::prev

template< std::size_t N = sizeof...(Vs) >
constexpr void /*prev*/();
(since C++23)
(exposition only*)

If called with default template parameter, recursively generates the previous element (the tuple of iterators) in cartesian_product_view.

Let current_ denote the underlying tuple of iterators. Equivalent to:

auto& it = std::get<N>(current_);
if constexpr (N > 0)
{
    if (it == ranges::begin(std::get<N>(parent_->bases_)))
    {
        it = /*cartesian-common-arg-end*/(std::get<N>(parent_->bases_));
        prev<N - 1>();
    }
}
--it;

Used in the following non-static member functions:

std::ranges::cartesian_product_view::iterator::distance_from

template< class Tuple >

constexpr difference_type

    /*distance-from*/( const Tuple& t ) const;
(since C++23)
(exposition only*)

Returns the "distance" (i.e., number of "hops") between two iterators.

Let:

  • parent_ be the underlying pointer to cartesian_product_view
  • /*scaled-size*/(N) be:
    • the product of static_cast<difference_type>(ranges::size(std::get<N>(parent_->bases_))) and /*scaled-size*/(N + 1) if N ≤ sizeof...(Vs), otherwise
    • static_cast<difference_type>(1);
  • /*scaled-distance*/(N) be the product of static_cast<difference_type>(std::get<N>(current_) - std::get<N>(t)) and /*scaled-size*/(N + 1);
  • /*scaled-sum*/ be the sum of /*scaled-distance*/(N) for every integer 0 ≤ N ≤ sizeof...(Vs).

Returns: /*scaled-sum*/.

The behavior is undefined if /*scaled-sum*/ cannot be represented by difference_type.

Used in the following functions:

Parameters

t - a tuple of iterators to find the distance to