Difference between revisions of "cpp/container/multimap"
(+pmr) |
(P0181R1) |
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| Line 3: | Line 3: | ||
{{dcl begin}} | {{dcl begin}} | ||
{{dcl header|map}} | {{dcl header|map}} | ||
| − | {{dcl|num=1| | + | {{dcl rev begin| num=1 }} |
| + | {{dcl | until=c++17 | | ||
template< | template< | ||
class Key, | class Key, | ||
| Line 11: | Line 12: | ||
> class multimap; | > class multimap; | ||
}} | }} | ||
| + | {{dcl | since=c++17 | | ||
| + | template< | ||
| + | class Key, | ||
| + | class T, | ||
| + | class Compare {{=}} std::default_order_t<Key>, | ||
| + | class Allocator {{=}} std::allocator<std::pair<const Key, T> > | ||
| + | > class multimap; | ||
| + | }} | ||
| + | {{dcl rev end}} | ||
{{dcl|num=2|since=c++17|1= | {{dcl|num=2|since=c++17|1= | ||
namespace pmr { | namespace pmr { | ||
| − | template <class Key, class T, class Compare = std:: | + | template <class Key, class T, class Compare = std::default_order_t<Key>> |
using multimap = std::multimap<Key, T, Compare, | using multimap = std::multimap<Key, T, Compare, | ||
| − | + | std::polymorphic_allocator<std::pair<const Key,T>>> | |
} | } | ||
| − | }} | + | }} |
{{dcl end}} | {{dcl end}} | ||
| − | + | {{tt|std::multimap}} is an associative container that contains a sorted list of key-value pairs. Sorting is done according to the comparison function {{tt|Compare}}, applied to the keys. Search, insertion, and removal operations have logarithmic complexity. | |
The order of the key-value pairs whose keys compare equivalent is the order of insertion and does not change. {{mark since c++11}} | The order of the key-value pairs whose keys compare equivalent is the order of insertion and does not change. {{mark since c++11}} | ||
Revision as of 21:19, 30 June 2016
| Defined in header <map>
|
||
| (1) | ||
| template< class Key, |
(until C++17) | |
| template< class Key, |
(since C++17) | |
| namespace pmr { template <class Key, class T, class Compare = std::default_order_t<Key>> |
(2) | (since C++17) |
std::multimap is an associative container that contains a sorted list of key-value pairs. Sorting is done according to the comparison function Compare, applied to the keys. Search, insertion, and removal operations have logarithmic complexity.
The order of the key-value pairs whose keys compare equivalent is the order of insertion and does not change. (since C++11)
Everywhere the standard library uses the Template:concept concept, equivalence is determined by using the equivalence relation as described on Template:concept. In imprecise terms, two objects a and b are considered equivalent if neither compares less than the other: !comp(a, b) && !comp(b, a).
std::multimap meets the requirements of Template:concept, Template:concept, Template:concept and Template:concept.
Contents |
Member types
| Member type | Definition | ||||
key_type
|
Key
| ||||
mapped_type
|
T
| ||||
value_type
|
std::pair<const Key, T> | ||||
size_type
|
Unsigned integer type (usually std::size_t) | ||||
difference_type
|
Signed integer type (usually std::ptrdiff_t) | ||||
key_compare
|
Compare
| ||||
allocator_type
|
Allocator
| ||||
reference
|
value_type& | ||||
const_reference
|
const value_type& | ||||
pointer
|
| ||||
const_pointer
|
| ||||
iterator
|
LegacyBidirectionalIterator to value_type
| ||||
const_iterator
|
LegacyBidirectionalIterator to const value_type | ||||
reverse_iterator
|
std::reverse_iterator<iterator> | ||||
const_reverse_iterator
|
std::reverse_iterator<const_iterator> |
Member classes
compares objects of type value_type (class) |
Member functions
constructs the multimap (public member function) | |
destructs the multimap (public member function) | |
| assigns values to the container (public member function) | |
| returns the associated allocator (public member function) | |
Iterators | |
| (C++11) |
returns an iterator to the beginning (public member function) |
| (C++11) |
returns an iterator to the end (public member function) |
| (C++11) |
returns a reverse iterator to the beginning (public member function) |
| (C++11) |
returns a reverse iterator to the end (public member function) |
Capacity | |
| checks whether the container is empty (public member function) | |
| returns the number of elements (public member function) | |
| returns the maximum possible number of elements (public member function) | |
Modifiers | |
| clears the contents (public member function) | |
| inserts elements or nodes(since C++17) (public member function) | |
| (C++11) |
constructs element in-place (public member function) |
| (C++11) |
constructs elements in-place using a hint (public member function) |
| erases elements (public member function) | |
| swaps the contents (public member function) | |
Lookup | |
| returns the number of elements matching specific key (public member function) | |
| finds element with specific key (public member function) | |
| returns range of elements matching a specific key (public member function) | |
| returns an iterator to the first element not less than the given key (public member function) | |
| returns an iterator to the first element greater than the given key (public member function) | |
Observers | |
| returns the function that compares keys (public member function) | |
returns the function that compares keys in objects of type value_type (public member function) | |
Non-member functions
| (removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20) |
lexicographically compares the values of two multimaps (function template) |
| specializes the std::swap algorithm (function template) |
