operator+,-(ranges::transform_view::iterator)
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.
Parameters
| i, x, y | - | the iterators. |
| n | - | position relative to current location. |
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_
Example
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 |
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