std::multimap - Man Page

typedef _Alloc allocator_type
typedef _Rep_type::const_iterator const_iterator
typedef _Alloc_traits::const_pointer const_pointer
typedef _Alloc_traits::const_reference const_reference
typedef _Rep_type::const_reverse_iterator const_reverse_iterator
typedef _Rep_type::difference_type difference_type
typedef _Rep_type::iterator iterator
typedef _Compare key_compare
typedef _Key key_type
typedef _Tp mapped_type
using node_type
typedef _Alloc_traits::pointer pointer
typedef _Alloc_traits::reference reference
typedef _Rep_type::reverse_iterator reverse_iterator
typedef _Rep_type::size_type size_type
typedef std::pair< const _Key, _Tp > value_type

multimap ()=default
Default constructor creates no elements.
template<typename _InputIterator > multimap (_InputIterator __first, _InputIterator __last)
Builds a multimap from a range.
template<typename _InputIterator > multimap (_InputIterator __first, _InputIterator __last, const _Compare &__comp, const allocator_type &__a=allocator_type())
Builds a multimap from a range.
template<typename _InputIterator > multimap (_InputIterator __first, _InputIterator __last, const allocator_type &__a)
Allocator-extended range constructor.
multimap (const _Compare &__comp, const allocator_type &__a=allocator_type())
Creates a multimap with no elements.
multimap (const allocator_type &__a)
Allocator-extended default constructor.
multimap (const multimap &)=default
Multimap copy constructor.
multimap (const multimap &__m, const __type_identity_t< allocator_type > &__a)
Allocator-extended copy constructor.
multimap (initializer_list< value_type > __l, const _Compare &__comp=_Compare(), const allocator_type &__a=allocator_type())
Builds a multimap from an initializer_list.
multimap (initializer_list< value_type > __l, const allocator_type &__a)
Allocator-extended initialier-list constructor.
multimap (multimap &&)=default
Multimap move constructor.
multimap (multimap &&__m, const __type_identity_t< allocator_type > &__a) noexcept(is_nothrow_copy_constructible< _Compare >::value &&_Alloc_traits::_S_always_equal())
Allocator-extended move constructor.
~multimap ()=default
const_iterator begin () const noexcept
iterator begin () noexcept
const_iterator cbegin () const noexcept
const_iterator cend () const noexcept
void clear () noexcept
const_reverse_iterator crbegin () const noexcept
const_reverse_iterator crend () const noexcept
template<typename... _Args> iterator emplace (_Args &&... __args)
Build and insert a std::pair into the multimap.
template<typename... _Args> iterator emplace_hint (const_iterator __pos, _Args &&... __args)
Builds and inserts a std::pair into the multimap.
bool empty () const noexcept
const_iterator end () const noexcept
iterator end () noexcept
size_type erase (const key_type &__x)
Erases elements according to the provided key.
iterator erase (const_iterator __first, const_iterator __last)
Erases a [first,last) range of elements from a multimap.
node_type extract (const key_type &__x)
Extract a node.
node_type extract (const_iterator __pos)
Extract a node.
allocator_type get_allocator () const noexcept
Get a copy of the memory allocation object.
template<typename _InputIterator > void insert (_InputIterator __first, _InputIterator __last)
A template function that attempts to insert a range of elements.
iterator insert (const_iterator __hint, node_type &&__nh)
Re-insert an extracted node.
void insert (initializer_list< value_type > __l)
Attempts to insert a list of std::pairs into the multimap.
iterator insert (node_type &&__nh)
Re-insert an extracted node.
key_compare key_comp () const
size_type max_size () const noexcept
template<typename _Cmp2 > void merge (map< _Key, _Tp, _Cmp2, _Alloc > &&__source)
template<typename _Cmp2 > void merge (map< _Key, _Tp, _Cmp2, _Alloc > &__source)
template<typename _Cmp2 > void merge (multimap< _Key, _Tp, _Cmp2, _Alloc > &&__source)
template<typename _Cmp2 > void merge (multimap< _Key, _Tp, _Cmp2, _Alloc > &__source)
multimap & operator= (const multimap &)=default
Multimap assignment operator.
multimap & operator= (initializer_list< value_type > __l)
Multimap list assignment operator.
multimap & operator= (multimap &&)=default
Move assignment operator.
const_reverse_iterator rbegin () const noexcept
reverse_iterator rbegin () noexcept
const_reverse_iterator rend () const noexcept
reverse_iterator rend () noexcept
size_type size () const noexcept
void swap (multimap &__x) noexcept(/*conditional */)
Swaps data with another multimap.
value_compare value_comp () const

iterator insert (const value_type &__x)
Inserts a std::pair into the multimap.
iterator insert (value_type &&__x)
Inserts a std::pair into the multimap.
template<typename _Pair > __enable_if_t< is_constructible< value_type, _Pair >::value, iterator > insert (_Pair &&__x)
Inserts a std::pair into the multimap.

iterator insert (const_iterator __position, const value_type &__x)
Inserts a std::pair into the multimap.
iterator insert (const_iterator __position, value_type &&__x)
Inserts a std::pair into the multimap.
template<typename _Pair > __enable_if_t< is_constructible< value_type, _Pair && >::value, iterator > insert (const_iterator __position, _Pair &&__x)
Inserts a std::pair into the multimap.

iterator erase (const_iterator __position)
Erases an element from a multimap.
_GLIBCXX_ABI_TAG_CXX11 iterator erase (iterator __position)
Erases an element from a multimap.

iterator find (const key_type &__x)
Tries to locate an element in a multimap.
template<typename _Kt > auto find (const _Kt &__x) -> decltype(_M_t._M_find_tr(__x))
Tries to locate an element in a multimap.

const_iterator find (const key_type &__x) const
Tries to locate an element in a multimap.
template<typename _Kt > auto find (const _Kt &__x) const -> decltype(_M_t._M_find_tr(__x))
Tries to locate an element in a multimap.

size_type count (const key_type &__x) const
Finds the number of elements with given key.
template<typename _Kt > auto count (const _Kt &__x) const -> decltype(_M_t._M_count_tr(__x))
Finds the number of elements with given key.

bool contains (const key_type &__x) const
Finds whether an element with the given key exists.
template<typename _Kt > auto contains (const _Kt &__x) const -> decltype(_M_t._M_find_tr(__x), void(), true)
Finds whether an element with the given key exists.

iterator lower_bound (const key_type &__x)
Finds the beginning of a subsequence matching given key.
template<typename _Kt > auto lower_bound (const _Kt &__x) -> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
Finds the beginning of a subsequence matching given key.

const_iterator lower_bound (const key_type &__x) const
Finds the beginning of a subsequence matching given key.
template<typename _Kt > auto lower_bound (const _Kt &__x) const -> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
Finds the beginning of a subsequence matching given key.

iterator upper_bound (const key_type &__x)
Finds the end of a subsequence matching given key.
template<typename _Kt > auto upper_bound (const _Kt &__x) -> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
Finds the end of a subsequence matching given key.

const_iterator upper_bound (const key_type &__x) const
Finds the end of a subsequence matching given key.
template<typename _Kt > auto upper_bound (const _Kt &__x) const -> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))
Finds the end of a subsequence matching given key.

std::pair< iterator, iterator > equal_range (const key_type &__x)
Finds a subsequence matching given key.
template<typename _Kt > auto equal_range (const _Kt &__x) -> decltype(pair< iterator, iterator >(_M_t._M_equal_range_tr(__x)))
Finds a subsequence matching given key.

std::pair< const_iterator, const_iterator > equal_range (const key_type &__x) const
Finds a subsequence matching given key.
template<typename _Kt > auto equal_range (const _Kt &__x) const -> decltype(pair< const_iterator, const_iterator >(_M_t._M_equal_range_tr(__x)))
Finds a subsequence matching given key.

template<typename _K1 , typename _T1 , typename _C1 , typename _A1 > bool operator< (const multimap< _K1, _T1, _C1, _A1 > &, const multimap< _K1, _T1, _C1, _A1 > &)
template<typename _K1 , typename _T1 , typename _C1 , typename _A1 > bool operator== (const multimap< _K1, _T1, _C1, _A1 > &, const multimap< _K1, _T1, _C1, _A1 > &)
template<typename , typename > struct std::_Rb_tree_merge_helper

class std::multimap< _Key, _Tp, _Compare, _Alloc >"A standard container made up of (key,value) pairs, which can be retrieved based on a key, in logarithmic time.

Since

C++98

Template Parameters

Meets the requirements of a container, a reversible container, and an associative container (using equivalent keys). For a multimap<Key,T> the key_type is Key, the mapped_type is T, and the value_type is std::pair<const Key,T>.

Multimaps support bidirectional iterators.

The private tree data is declared exactly the same way for map and multimap; the distinction is made entirely in how the tree functions are called (*_unique versus *_equal, same as the standard).

Default constructor creates no elements.

Creates a multimap with no elements.

Parameters

Multimap copy constructor. Whether the allocator is copied depends on the allocator traits.

Multimap move constructor. The newly-created multimap contains the exact contents of the moved instance. The moved instance is a valid, but unspecified multimap.

Builds a multimap from an initializer_list.

Parameters

Create a multimap consisting of copies of the elements from the initializer_list. This is linear in N if the list is already sorted, and NlogN otherwise (where N is __l.size()).

Allocator-extended default constructor.

Allocator-extended copy constructor.

Allocator-extended move constructor.

Allocator-extended initialier-list constructor.

Allocator-extended range constructor.

Builds a multimap from a range.

Parameters

Create a multimap consisting of copies of the elements from [__first,__last). This is linear in N if the range is already sorted, and NlogN otherwise (where N is distance(__first,__last)).

Builds a multimap from a range.

Parameters

Create a multimap consisting of copies of the elements from [__first,__last). This is linear in N if the range is already sorted, and NlogN otherwise (where N is distance(__first,__last)).

The dtor only erases the elements, and note that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Returns a read-only (constant) iterator that points to the first pair in the multimap. Iteration is done in ascending order according to the keys.

Returns a read/write iterator that points to the first pair in the multimap. Iteration is done in ascending order according to the keys.

Returns a read-only (constant) iterator that points to the first pair in the multimap. Iteration is done in ascending order according to the keys.

Returns a read-only (constant) iterator that points one past the last pair in the multimap. Iteration is done in ascending order according to the keys.

Erases all elements in a multimap. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

[inline]"

Finds whether an element with the given key exists.

Parameters

Returns

True if there is any element with the specified key.

Finds whether an element with the given key exists.

Parameters

Returns

True if there is any element with the specified key.

[inline]"

Finds the number of elements with given key.

Parameters

Returns

Number of elements with specified key.

Finds the number of elements with given key.

Parameters

Returns

Number of elements with specified key.

Returns a read-only (constant) reverse iterator that points to the last pair in the multimap. Iteration is done in descending order according to the keys.

Returns a read-only (constant) reverse iterator that points to one before the first pair in the multimap. Iteration is done in descending order according to the keys.

Build and insert a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function builds and inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted.

Insertion requires logarithmic time.

References std::forward().

Builds and inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

For more on hinting, see: https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints

Insertion requires logarithmic time (if the hint is not taken).

References std::forward().

Returns true if the multimap is empty.

Returns a read-only (constant) iterator that points one past the last pair in the multimap. Iteration is done in ascending order according to the keys.

Returns a read/write iterator that points one past the last pair in the multimap. Iteration is done in ascending order according to the keys.

Referenced by std::multimap< _Key, _Tp, _Compare, _Alloc >::extract().

[inline]"

Finds a subsequence matching given key.

Parameters

Returns

Pair of iterators that possibly points to the subsequence matching given key.

This function is equivalent to

std::make_pair(c.lower_bound(val),
               c.upper_bound(val))

(but is faster than making the calls separately).

     _M_t._M_equal_range_tr(__x))) [inline]"

Finds a subsequence matching given key.

Parameters

Returns

Pair of read-only (constant) iterators that possibly points to the subsequence matching given key.

This function is equivalent to

std::make_pair(c.lower_bound(val),
               c.upper_bound(val))

(but is faster than making the calls separately).

Finds a subsequence matching given key.

Parameters

Returns

Pair of iterators that possibly points to the subsequence matching given key.

This function is equivalent to

std::make_pair(c.lower_bound(val),
               c.upper_bound(val))

(but is faster than making the calls separately).

Finds a subsequence matching given key.

Parameters

Returns

Pair of read-only (constant) iterators that possibly points to the subsequence matching given key.

This function is equivalent to

std::make_pair(c.lower_bound(val),
               c.upper_bound(val))

(but is faster than making the calls separately).

Erases elements according to the provided key.

Parameters

Returns

The number of elements erased.

This function erases all elements located by the given key from a multimap. Note that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Erases a [first,last) range of elements from a multimap.

Parameters

Returns

The iterator __last.

This function erases a sequence of elements from a multimap. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Erases an element from a multimap.

Parameters

Returns

An iterator pointing to the element immediately following position prior to the element being erased. If no such element exists, end() is returned.

This function erases an element, pointed to by the given iterator, from a multimap. Note that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Erases an element from a multimap.

Parameters

Returns

An iterator pointing to the element immediately following position prior to the element being erased. If no such element exists, end() is returned.

This function erases an element, pointed to by the given iterator, from a multimap. Note that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Extract a node.

Extract a node.

References std::multimap< _Key, _Tp, _Compare, _Alloc >::end().

[inline]"

Tries to locate an element in a multimap.

Parameters

Returns

Iterator pointing to sought-after element, or end() if not found.

This function takes a key and tries to locate the element with which the key matches. If successful the function returns an iterator pointing to the sought after pair. If unsuccessful it returns the past-the-end ( end() ) iterator.

[inline]"

Tries to locate an element in a multimap.

Parameters

Returns

Read-only (constant) iterator pointing to sought-after element, or end() if not found.

This function takes a key and tries to locate the element with which the key matches. If successful the function returns a constant iterator pointing to the sought after pair. If unsuccessful it returns the past-the-end ( end() ) iterator.

Tries to locate an element in a multimap.

Parameters

Returns

Iterator pointing to sought-after element, or end() if not found.

This function takes a key and tries to locate the element with which the key matches. If successful the function returns an iterator pointing to the sought after pair. If unsuccessful it returns the past-the-end ( end() ) iterator.

Tries to locate an element in a multimap.

Parameters

Returns

Read-only (constant) iterator pointing to sought-after element, or end() if not found.

This function takes a key and tries to locate the element with which the key matches. If successful the function returns a constant iterator pointing to the sought after pair. If unsuccessful it returns the past-the-end ( end() ) iterator.

Get a copy of the memory allocation object.

A template function that attempts to insert a range of elements.

Parameters

Complexity similar to that of the range constructor.

Inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted.

Insertion requires logarithmic time.

References std::forward().

Inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted.

Insertion requires logarithmic time.

Referenced by std::multimap< _Key, _Tp, _Compare, _Alloc >::insert().

Re-insert an extracted node.

References std::move().

Inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

For more on hinting, see: https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints

Insertion requires logarithmic time (if the hint is not taken).

References std::forward().

Inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

For more on hinting, see: https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints

Insertion requires logarithmic time (if the hint is not taken).

Inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

For more on hinting, see: https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints

Insertion requires logarithmic time (if the hint is not taken).

References std::move().

Attempts to insert a list of std::pairs into the multimap.

Parameters

Complexity similar to that of the range constructor.

References std::multimap< _Key, _Tp, _Compare, _Alloc >::insert().

Re-insert an extracted node.

References std::move().

Inserts a std::pair into the multimap.

Parameters

Returns

An iterator that points to the inserted (key,value) pair.

This function inserts a (key, value) pair into the multimap. Contrary to a std::map the multimap does not rely on unique keys and thus multiple pairs with the same key can be inserted.

Insertion requires logarithmic time.

References std::move().

Returns the key comparison object out of which the multimap was constructed.

[inline]"

Finds the beginning of a subsequence matching given key.

Parameters

Returns

Iterator pointing to first element equal to or greater than key, or end().

This function returns the first element of a subsequence of elements that matches the given key. If unsuccessful it returns an iterator pointing to the first element that has a greater value than given key or end() if no such element exists.

[inline]"

Finds the beginning of a subsequence matching given key.

Parameters

Returns

Read-only (constant) iterator pointing to first element equal to or greater than key, or end().

This function returns the first element of a subsequence of elements that matches the given key. If unsuccessful the iterator will point to the next greatest element or, if no such greater element exists, to end().

Finds the beginning of a subsequence matching given key.

Parameters

Returns

Iterator pointing to first element equal to or greater than key, or end().

This function returns the first element of a subsequence of elements that matches the given key. If unsuccessful it returns an iterator pointing to the first element that has a greater value than given key or end() if no such element exists.

Finds the beginning of a subsequence matching given key.

Parameters

Returns

Read-only (constant) iterator pointing to first element equal to or greater than key, or end().

This function returns the first element of a subsequence of elements that matches the given key. If unsuccessful the iterator will point to the next greatest element or, if no such greater element exists, to end().

Returns the maximum size of the multimap.

Multimap assignment operator. Whether the allocator is copied depends on the allocator traits.

Multimap list assignment operator.

Parameters

This function fills a multimap with copies of the elements in the initializer list __l.

Note that the assignment completely changes the multimap and that the resulting multimap's size is the same as the number of elements assigned.

Move assignment operator.

Returns a read-only (constant) reverse iterator that points to the last pair in the multimap. Iteration is done in descending order according to the keys.

Returns a read/write reverse iterator that points to the last pair in the multimap. Iteration is done in descending order according to the keys.

Returns a read-only (constant) reverse iterator that points to one before the first pair in the multimap. Iteration is done in descending order according to the keys.

Returns a read/write reverse iterator that points to one before the first pair in the multimap. Iteration is done in descending order according to the keys.

Returns the size of the multimap.

Swaps data with another multimap.

Parameters

This exchanges the elements between two multimaps in constant time. (It is only swapping a pointer, an integer, and an instance of the Compare type (which itself is often stateless and empty), so it should be quite fast.) Note that the global std::swap() function is specialized such that std::swap(m1,m2) will feed to this function.

Whether the allocators are swapped depends on the allocator traits.

[inline]"

Finds the end of a subsequence matching given key.

Parameters

Returns

Iterator pointing to the first element greater than key, or end().

[inline]"

Finds the end of a subsequence matching given key.

Parameters

Returns

Read-only (constant) iterator pointing to first iterator greater than key, or end().

Finds the end of a subsequence matching given key.

Parameters

Returns

Iterator pointing to the first element greater than key, or end().

Finds the end of a subsequence matching given key.

Parameters

Returns

Read-only (constant) iterator pointing to first iterator greater than key, or end().

Returns a value comparison object, built from the key comparison object out of which the multimap was constructed.