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operator+,-(ranges::transform_view::iterator)

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Ranges library
Range access
Range conversions
(C++23)

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(until C++23)(C++23)


 
 
friend constexpr /*iterator*/ operator+( /*iterator*/ i, difference_type n )
    requires ranges::random_access_range<Base>;
(1) (since C++20)
friend constexpr /*iterator*/ operator+( difference_type n, /*iterator*/ i )
    requires ranges::random_access_range<Base>;
(2) (since C++20)
friend constexpr /*iterator*/ operator-( /*iterator*/ i, difference_type n )
    requires ranges::random_access_range<Base>;
(3) (since C++20)
friend constexpr difference_type operator-( const /*iterator*/& x,

                                            const /*iterator*/& y )

    requires std::sized_sentinel_for<ranges::iterator_t<Base>, ranges::iterator_t<Base>>;
(4) (since C++20)
1,2) Returns the iterator i incremented by n.
3) Returns the iterator i decremented by n.
4) Returns the distance between x and y.

These functions are not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when transform_view::iterator<Const> is an associated class of the arguments.

Contents

[edit] Parameters

i, x, y - the iterators.
n - position relative to current location.

[edit] Return value

Let parent_ denote the pointer to the parent transform_view, current_ denote the underlying iterator.

1,2) /*iterator*/{*i.parent_, i.current_ + n}
3) /*iterator*/{*i.parent_, i.current_ - n}
4) x.current_ - y.current_

[edit] Example

[edit] Defect reports

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

DR Applied to Behavior as published Correct behavior
LWG 3483 C++20 transform_view::iterator's difference is overconstrained requirement is relaxed