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std::ranges::join_view<V>::iterator<Const>::operator++,--

constexpr /*iterator*/& operator++();
 (1) (since C++20) 
constexpr void operator++( int );
 (2) (since C++20) 
constexpr /*iterator*/ operator++( int )
  requires /*ref-is-glvalue*/ && ranges::forward_range<Base> &&
           ranges::forward_range<ranges::range_reference_t<Base>>;
 (3) (since C++20) 
constexpr iterator& operator--()
  requires /*ref-is-glvalue*/ && ranges::bidirectional_range<Base> &&
           ranges::bidirectional_range<ranges::range_reference_t<Base>> &&
           ranges::common_range<ranges::range_reference_t<Base>>;
 (4) (since C++20) 
constexpr /*iterator*/ operator--( int )
  requires /*ref-is-glvalue*/ && ranges::bidirectional_range<Base> &&
           ranges::bidirectional_range<ranges::range_reference_t<Base>> &&
           ranges::common_range<ranges::range_reference_t<Base>>;
 (5) (since C++20)

Increments or decrements the underlying iterator.

Let inner_ and outer_ be the underlying iterators, and parent_ be the pointer to parent ranges::join_view, the constant /*ref-is-glvalue*/ be std::is_reference_v<ranges::range_reference_t<Base>>.

1) Let /*inner-range*/ be:
  • *outer_, if /*ref-is-glvalue*/ == true;
  • *parent_->inner_ otherwise.

Equivalent to:

auto&& inner_rng = /*inner-range*/;
if (++inner_ == ranges::end(inner_rng)) {
    ++outer_;
    satisfy();
}
return *this;
2) Equivalent to: ++*this.
3) Equivalent to: 
auto tmp = *this;
++*this;
return tmp;
4) Equivalent to: 
if (outer_ == ranges::end(parent_->base_))
    inner_ = ranges::end(*--outer_);
while (inner_ == ranges::begin(*outer_))
    inner_ = ranges::end(*--outer_);
--inner_;
return *this;
5) Equivalent to: 
auto tmp = *this;
--*this;
return tmp;

Parameters

(none)

Return value

1,4) *this
2) (none)
3,5) a copy of *this that was made before the change

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https://en.cppreference.com/w/cpp/ranges/join_view/iterator/operator_arith