[common.iter.nav]

# 24 Iterators library [[iterators]](./#iterators)

## 24.5 Iterator adaptors [[predef.iterators]](predef.iterators#common.iter.nav)

### 24.5.5 Common iterators [[iterators.common]](iterators.common#common.iter.nav)

#### 24.5.5.5 Navigation [common.iter.nav]

[ð](#lib:operator++,common_iterator)

`constexpr common_iterator& operator++();
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iterators.tex#L5693)

*Hardened preconditions*: holds_alternative<I>(v_) is true[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iterators.tex#L5697)

*Effects*: Equivalent to ++get<I>(v_)[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iterators.tex#L5701)

*Returns*: *this[.](#3.sentence-1)

[ð](#lib:operator++,common_iterator_)

`constexpr decltype(auto) operator++(int);
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iterators.tex#L5712)

*Hardened preconditions*: holds_alternative<I>(v_) is true[.](#4.sentence-1)

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iterators.tex#L5716)

*Effects*: If I models [forward_iterator](iterator.concept.forward#concept:forward_iterator "24.3.4.11 Concept forward_­iterator [iterator.concept.forward]"), equivalent to:common_iterator tmp = *this;++*this;return tmp;

Otherwise, ifrequires(I& i) { { *i++ } -> [*can-reference*](iterator.synopsis#concept:can-reference "24.2 Header <iterator>&nbsp;synopsis [iterator.synopsis]"); } is true or[indirectly_readable](iterator.concept.readable#concept:indirectly_readable "24.3.4.2 Concept indirectly_­readable [iterator.concept.readable]")<I> && [constructible_from](concept.constructible#concept:constructible_from "18.4.11 Concept constructible_­from [concept.constructible]")<iter_value_t<I>, iter_reference_t<I>> &&[move_constructible](concept.moveconstructible#concept:move_constructible "18.4.13 Concept move_­constructible [concept.moveconstructible]")<iter_value_t<I>> is false,
equivalent to:return get<I>(v_)++;

Otherwise, equivalent to:*postfix-proxy* p(**this);++*this;return p; where *postfix-proxy* is the exposition-only class:class *postfix-proxy* { iter_value_t<I> keep_; constexpr *postfix-proxy*(iter_reference_t<I>&& x): keep_(std::forward<iter_reference_t<I>>(x)) {}public:constexpr const iter_value_t<I>& operator*() const noexcept {return keep_; }};
