std::multimap
Defined in header <map>
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||
template< class Key, |
(1) | |
namespace pmr { template <class Key, class T, class Compare = std::less<Key>> |
(2) | (since C++17) |
Multimap is an associative container that contains a sorted list of key-value pairs, while multiple entries with the same key is permitted. 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 Compare
concept, equivalence is determined by using the equivalence relation as described on Compare
. 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 Container
, AllocatorAwareContainer
, AssociativeContainer
and ReversibleContainer
.
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
|
| ||||
const_reference
|
| ||||
pointer
|
| ||||
const_pointer
|
| ||||
iterator
|
BidirectionalIterator | ||||
const_iterator
|
Constant bidirectional iterator | ||||
reverse_iterator
|
std::reverse_iterator<iterator> | ||||
const_reverse_iterator
|
std::reverse_iterator<const_iterator> | ||||
node_type
|
a specialization of node handle representing a container node (since C++17) |
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 | |
returns an iterator to the beginning (public member function) | |
returns an iterator to the end (public member function) | |
returns a reverse iterator to the beginning (public member function) | |
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) | |
(C++17) |
extracts nodes from the container (public member function) |
(C++17) |
splices nodes from another container (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
lexicographically compares the values in the multimap (function template) | |
specializes the std::swap algorithm (function template) |