[associative.general]

# 23 Containers library [[containers]](./#containers)

## 23.4 Associative containers [[associative]](associative#general)

### 23.4.1 General [associative.general]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L11363)

The header [<map>](associative.map.syn#header:%3cmap%3e "23.4.2 Header <map> synopsis [associative.map.syn]") defines the class templatesmap and multimap;
the header [<set>](associative.set.syn#header:%3cset%3e "23.4.5 Header <set> synopsis [associative.set.syn]") defines the class templatesset and multiset[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L11369)

The following exposition-only alias templates may appear in deduction guides for associative containers:template<class InputIterator>using *iter-value-type* =typename iterator_traits<InputIterator>::value_type; // *exposition only*template<class InputIterator>using *iter-key-type* = remove_const_t< tuple_element_t<0, *iter-value-type*<InputIterator>>>; // *exposition only*template<class InputIterator>using *iter-mapped-type* = tuple_element_t<1, *iter-value-type*<InputIterator>>; // *exposition only*template<class InputIterator>using *iter-to-alloc-type* = pair< add_const_t<tuple_element_t<0, *iter-value-type*<InputIterator>>>,
 tuple_element_t<1, *iter-value-type*<InputIterator>>>; // *exposition only*template<ranges::[input_range](range.refinements#concept:input_range "25.4.6 Other range refinements [range.refinements]") Range>using *range-key-type* = remove_const_t<typename ranges::range_value_t<Range>::first_type>; // *exposition only*template<ranges::[input_range](range.refinements#concept:input_range "25.4.6 Other range refinements [range.refinements]") Range>using *range-mapped-type* = typename ranges::range_value_t<Range>::second_type; // *exposition only*template<ranges::[input_range](range.refinements#concept:input_range "25.4.6 Other range refinements [range.refinements]") Range>using *range-to-alloc-type* = pair<add_const_t<typename ranges::range_value_t<Range>::first_type>, typename ranges::range_value_t<Range>::second_type>; // *exposition only*