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std::map< _Key, _Tp, _Compare, _Alloc >(3cxx) std::map< _Key, _Tp, _Compare, _Alloc >(3cxx)

NAME

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

SYNOPSIS

Public Types


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
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

Public Member Functions


map ()=default
Default constructor creates no elements. template<typename _InputIterator > map (_InputIterator __first, _InputIterator __last)
Builds a map from a range. template<typename _InputIterator > map (_InputIterator __first, _InputIterator __last, const _Compare &__comp, const allocator_type &__a=allocator_type())
Builds a map from a range. template<typename _InputIterator > map (_InputIterator __first, _InputIterator __last, const allocator_type &__a)
Allocator-extended range constructor. map (const _Compare &__comp, const allocator_type &__a=allocator_type())
Creates a map with no elements. map (const allocator_type &__a)
Allocator-extended default constructor. map (const map &)=default
Map copy constructor. map (const map &__m, const allocator_type &__a)
Allocator-extended copy constructor. map (initializer_list< value_type > __l, const _Compare &__comp=_Compare(), const allocator_type &__a=allocator_type())
Builds a map from an initializer_list. map (initializer_list< value_type > __l, const allocator_type &__a)
Allocator-extended initialier-list constructor. map (map &&)=default
Map move constructor. map (map &&__m, const allocator_type &__a) noexcept(is_nothrow_copy_constructible< _Compare >::value &&_Alloc_traits::_S_always_equal())
Allocator-extended move constructor. ~map ()=default
mapped_type & at (const key_type &__k)
Access to map data. const mapped_type & at (const key_type &__k) const
const_iterator begin () const noexcept
iterator begin () noexcept
const_iterator cbegin () const noexcept
const_iterator cend () const noexcept
const_reverse_iterator crbegin () const noexcept
const_reverse_iterator crend () const noexcept
template<typename... _Args> std::pair< iterator, bool > emplace (_Args &&... __args)
Attempts to build and insert a std::pair into the map. template<typename... _Args> iterator emplace_hint (const_iterator __pos, _Args &&... __args)
Attempts to build and insert a std::pair into the map. _GLIBCXX_NODISCARD bool empty () const noexcept
const_iterator end () const noexcept
iterator end () noexcept
allocator_type get_allocator () const noexcept
Get a copy of the memory allocation object. size_type max_size () const noexcept
map & operator= (const map &)=default
Map assignment operator. map & operator= (initializer_list< value_type > __l)
Map list assignment operator. map & operator= (map &&)=default
Move assignment operator. mapped_type & operator[] (const key_type &__k)
Subscript ( [] ) access to map data. mapped_type & operator[] (key_type &&__k)
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


std::pair< iterator, bool > insert (const value_type &__x)
Attempts to insert a std::pair into the map. std::pair< iterator, bool > insert (value_type &&__x)
Attempts to insert a std::pair into the map. template<typename _Pair > __enable_if_t< is_constructible< value_type, _Pair >::value, pair< iterator, bool > > insert (_Pair &&__x)
Attempts to insert a std::pair into the map. void insert (std::initializer_list< value_type > __list)
Attempts to insert a list of std::pairs into the map. iterator insert (const_iterator __position, const value_type &__x)
Attempts to insert a std::pair into the map. iterator insert (const_iterator __position, value_type &&__x)
Attempts to insert a std::pair into the map. template<typename _Pair > __enable_if_t< is_constructible< value_type, _Pair >::value, iterator > insert (const_iterator __position, _Pair &&__x)
Attempts to insert a std::pair into the map. template<typename _InputIterator > void insert (_InputIterator __first, _InputIterator __last)
Template function that attempts to insert a range of elements. iterator erase (const_iterator __position)
Erases an element from a map. _GLIBCXX_ABI_TAG_CXX11 iterator erase (iterator __position)
Attempts to insert a std::pair into the map. 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 map. void swap (map &__x) noexcept(/*conditional */)
Swaps data with another map. void clear () noexcept
key_compare key_comp () const
value_compare value_comp () const
iterator find (const key_type &__x)
Tries to locate an element in a map. template<typename _Kt > auto find (const _Kt &__x) -> decltype(_M_t._M_find_tr(__x))
Attempts to insert a std::pair into the map. const_iterator find (const key_type &__x) const
Tries to locate an element in a map. template<typename _Kt > auto find (const _Kt &__x) const -> decltype(_M_t._M_find_tr(__x))
Attempts to insert a std::pair into the map. 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))
Attempts to insert a std::pair into the map. 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)))
Attempts to insert a std::pair into the map. 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)))
Attempts to insert a std::pair into the map. 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)))
Attempts to insert a std::pair into the map. 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)))
Attempts to insert a std::pair into the map. 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)))
Attempts to insert a std::pair into the map. 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)))
Attempts to insert a std::pair into the map. template<typename _K1 , typename _T1 , typename _C1 , typename _A1 > bool operator== (const map< _K1, _T1, _C1, _A1 > &, const map< _K1, _T1, _C1, _A1 > &)
Attempts to insert a std::pair into the map. template<typename _K1 , typename _T1 , typename _C1 , typename _A1 > bool operator< (const map< _K1, _T1, _C1, _A1 > &, const map< _K1, _T1, _C1, _A1 > &)
Attempts to insert a std::pair into the map.

Detailed Description

template<typename _Key, typename _Tp, typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >>

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

Template Parameters

_Key Type of key objects.
_Tp Type of mapped objects.
_Compare Comparison function object type, defaults to less<_Key>.
_Alloc Allocator type, defaults to allocator<pair<const _Key, _Tp>.

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

Maps 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).

Definition at line 100 of file stl_map.h.

Constructor & Destructor Documentation

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map () [default]

Default constructor creates no elements.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (const _Compare & __comp, const allocator_type & __a = allocator_type()) [inline], [explicit]

Creates a map with no elements.

Parameters

__comp A comparison object.
__a An allocator object.

Definition at line 192 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (const map< _Key, _Tp, _Compare, _Alloc > &) [default]

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

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (map< _Key, _Tp, _Compare, _Alloc > &&) [default]

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

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (initializer_list< value_type > __l, const _Compare & __comp = _Compare(), const allocator_type & __a = allocator_type()) [inline]

Builds a map from an initializer_list.

Parameters

__l An initializer_list.
__comp A comparison object.
__a An allocator object.

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

Definition at line 226 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (const allocator_type & __a) [inline], [explicit]

Allocator-extended default constructor.

Definition at line 234 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (const map< _Key, _Tp, _Compare, _Alloc > & __m, const allocator_type & __a) [inline]

Allocator-extended copy constructor.

Definition at line 238 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (map< _Key, _Tp, _Compare, _Alloc > && __m, const allocator_type & __a) [inline], [noexcept]

Allocator-extended move constructor.

Definition at line 242 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::map (initializer_list< value_type > __l, const allocator_type & __a) [inline]

Allocator-extended initialier-list constructor.

Definition at line 248 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _InputIterator > std::map< _Key, _Tp, _Compare, _Alloc >::map (_InputIterator __first, _InputIterator __last, const allocator_type & __a) [inline]

Allocator-extended range constructor.

Definition at line 254 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _InputIterator > std::map< _Key, _Tp, _Compare, _Alloc >::map (_InputIterator __first, _InputIterator __last) [inline]

Builds a map from a range.

Parameters

__first An input iterator.
__last An input iterator.

Create a map 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)).

Definition at line 271 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _InputIterator > std::map< _Key, _Tp, _Compare, _Alloc >::map (_InputIterator __first, _InputIterator __last, const _Compare & __comp, const allocator_type & __a = allocator_type()) [inline]

Builds a map from a range.

Parameters

__first An input iterator.
__last An input iterator.
__comp A comparison functor.
__a An allocator object.

Create a map 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)).

Definition at line 288 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::map< _Key, _Tp, _Compare, _Alloc >::~map () [default]

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.

Member Function Documentation

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> mapped_type& std::map< _Key, _Tp, _Compare, _Alloc >::at (const key_type & __k) [inline]

Access to map data.

Parameters

__k The key for which data should be retrieved.

Returns

A reference to the data whose key is equivalent to __k, if such a data is present in the map.

Exceptions

std::out_of_range If no such data is present.

Definition at line 535 of file stl_map.h.

References std::map< _Key, _Tp, _Compare, _Alloc >::end(), std::map< _Key, _Tp, _Compare, _Alloc >::key_comp(), and std::map< _Key, _Tp, _Compare, _Alloc >::lower_bound().

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::begin () const [inline], [noexcept]

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

Definition at line 363 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::begin () [inline], [noexcept]

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

Definition at line 354 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::cbegin () const [inline], [noexcept]

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

Definition at line 427 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::cend () const [inline], [noexcept]

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

Definition at line 436 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> void std::map< _Key, _Tp, _Compare, _Alloc >::clear () [inline], [noexcept]

Erases all elements in a map. 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.

Definition at line 1132 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::count (const _Kt & __x) const -> decltype(_M_t._M_count_tr(__x))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1220 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> size_type std::map< _Key, _Tp, _Compare, _Alloc >::count (const key_type & __x) const [inline]

Finds the number of elements with given key.

Parameters

__x Key of (key, value) pairs to be located.

Returns

Number of elements with specified key.

This function only makes sense for multimaps; for map the result will either be 0 (not present) or 1 (present).

Definition at line 1214 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_reverse_iterator std::map< _Key, _Tp, _Compare, _Alloc >::crbegin () const [inline], [noexcept]

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

Definition at line 445 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_reverse_iterator std::map< _Key, _Tp, _Compare, _Alloc >::crend () const [inline], [noexcept]

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

Definition at line 454 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename... _Args> std::pair<iterator, bool> std::map< _Key, _Tp, _Compare, _Alloc >::emplace (_Args &&... __args) [inline]

Attempts to build and insert a std::pair into the map.

Parameters

__args Arguments used to generate a new pair instance (see std::piecewise_contruct for passing arguments to each part of the pair constructor).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to build and insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 574 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename... _Args> iterator std::map< _Key, _Tp, _Compare, _Alloc >::emplace_hint (const_iterator __pos, _Args &&... __args) [inline]

Attempts to build and insert a std::pair into the map.

Parameters

__pos An iterator that serves as a hint as to where the pair should be inserted.
__args Arguments used to generate a new pair instance (see std::piecewise_contruct for passing arguments to each part of the pair constructor).

Returns

An iterator that points to the element with key of the std::pair built from __args (may or may not be that std::pair).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument emplace() does. 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.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

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

Definition at line 604 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> _GLIBCXX_NODISCARD bool std::map< _Key, _Tp, _Compare, _Alloc >::empty () const [inline], [noexcept]

Returns true if the map is empty. (Thus begin() would equal end().)

Definition at line 463 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::end () const [inline], [noexcept]

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

Definition at line 381 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::end () [inline], [noexcept]

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

Definition at line 372 of file stl_map.h.

Referenced by std::map< _Key, _Tp, _Compare, _Alloc >::at().

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::equal_range (const _Kt & __x) -> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1357 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::equal_range (const _Kt & __x) const -> decltype(pair<const_iterator, const_iterator>(

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

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1386 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::pair<iterator, iterator> std::map< _Key, _Tp, _Compare, _Alloc >::equal_range (const key_type & __x) [inline]

Finds a subsequence matching given key.

Parameters

__x Key of (key, value) pairs to be located.

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).

This function probably only makes sense for multimaps.

Definition at line 1351 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::pair<const_iterator, const_iterator> std::map< _Key, _Tp, _Compare, _Alloc >::equal_range (const key_type & __x) const [inline]

Finds a subsequence matching given key.

Parameters

__x Key of (key, value) pairs to be located.

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).

This function probably only makes sense for multimaps.

Definition at line 1380 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> size_type std::map< _Key, _Tp, _Compare, _Alloc >::erase (const key_type & __x) [inline]

Erases elements according to the provided key.

Parameters

__x Key of element to be erased.

Returns

The number of elements erased.

This function erases all the elements located by the given key from a map. 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.

Definition at line 1067 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::erase (const_iterator __first, const_iterator __last) [inline]

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

Parameters

__first Iterator pointing to the start of the range to be erased.
__last Iterator pointing to the end of the range to be erased.

Returns

The iterator __last.

This function erases a sequence of elements from a map. 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.

Definition at line 1087 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::erase (const_iterator __position) [inline]

Erases an element from a map.

Parameters

__position An iterator pointing to the element to be erased.

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 map. 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.

Definition at line 1030 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> _GLIBCXX_ABI_TAG_CXX11 iterator std::map< _Key, _Tp, _Compare, _Alloc >::erase (iterator __position) [inline]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1036 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::find (const _Kt & __x) -> decltype(_M_t._M_find_tr(__x))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1174 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::find (const _Kt & __x) const -> decltype(_M_t._M_find_tr(__x))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1199 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::find (const key_type & __x) [inline]

Tries to locate an element in a map.

Parameters

__x Key of (key, value) pair to be located.

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.

Definition at line 1168 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::find (const key_type & __x) const [inline]

Tries to locate an element in a map.

Parameters

__x Key of (key, value) pair to be located.

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.

Definition at line 1193 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> allocator_type std::map< _Key, _Tp, _Compare, _Alloc >::get_allocator () const [inline], [noexcept]

Get a copy of the memory allocation object.

Definition at line 344 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _InputIterator > void std::map< _Key, _Tp, _Compare, _Alloc >::insert (_InputIterator __first, _InputIterator __last) [inline]

Template function that attempts to insert a range of elements.

Parameters

__first Iterator pointing to the start of the range to be inserted.
__last Iterator pointing to the end of the range.

Complexity similar to that of the range constructor.

Definition at line 891 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Pair > __enable_if_t<is_constructible<value_type, _Pair>::value, pair<iterator, bool> > std::map< _Key, _Tp, _Compare, _Alloc >::insert (_Pair && __x) [inline]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 814 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::pair<iterator, bool> std::map< _Key, _Tp, _Compare, _Alloc >::insert (const value_type & __x) [inline]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 801 of file stl_map.h.

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

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Pair > __enable_if_t<is_constructible<value_type, _Pair>::value, iterator> std::map< _Key, _Tp, _Compare, _Alloc >::insert (const_iterator __position, _Pair && __x) [inline]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 873 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::insert (const_iterator __position, const value_type & __x) [inline]

Attempts to insert a std::pair into the map.

Parameters

__position An iterator that serves as a hint as to where the pair should be inserted.
__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

An iterator that points to the element with key of __x (may or may not be the pair passed in).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument insert() does. 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.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

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

Definition at line 858 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::insert (const_iterator __position, value_type && __x) [inline]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 868 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> void std::map< _Key, _Tp, _Compare, _Alloc >::insert (std::initializer_list< value_type > __list) [inline]

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

Parameters

__list A std::initializer_list<value_type> of pairs to be inserted.

Complexity similar to that of the range constructor.

Definition at line 828 of file stl_map.h.

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

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> std::pair<iterator, bool> std::map< _Key, _Tp, _Compare, _Alloc >::insert (value_type && __x) [inline]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 808 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> key_compare std::map< _Key, _Tp, _Compare, _Alloc >::key_comp () const [inline]

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

Definition at line 1141 of file stl_map.h.

Referenced by std::map< _Key, _Tp, _Compare, _Alloc >::at().

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::lower_bound (const _Kt & __x) -> decltype(iterator(_M_t._M_lower_bound_tr(__x)))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1263 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::lower_bound (const _Kt & __x) const -> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1288 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::lower_bound (const key_type & __x) [inline]

Finds the beginning of a subsequence matching given key.

Parameters

__x Key of (key, value) pair to be located.

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.

Definition at line 1257 of file stl_map.h.

Referenced by std::map< _Key, _Tp, _Compare, _Alloc >::at().

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::lower_bound (const key_type & __x) const [inline]

Finds the beginning of a subsequence matching given key.

Parameters

__x Key of (key, value) pair to be located.

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 it returns an iterator pointing to the first element that has a greater value than given key or end() if no such element exists.

Definition at line 1282 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> size_type std::map< _Key, _Tp, _Compare, _Alloc >::max_size () const [inline], [noexcept]

Returns the maximum size of the map.

Definition at line 473 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> map& std::map< _Key, _Tp, _Compare, _Alloc >::operator= (const map< _Key, _Tp, _Compare, _Alloc > &) [default]

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

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> map& std::map< _Key, _Tp, _Compare, _Alloc >::operator= (initializer_list< value_type > __l) [inline]

Map list assignment operator.

Parameters

__l An initializer_list.

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

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

Definition at line 335 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> map& std::map< _Key, _Tp, _Compare, _Alloc >::operator= (map< _Key, _Tp, _Compare, _Alloc > &&) [default]

Move assignment operator.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> mapped_type& std::map< _Key, _Tp, _Compare, _Alloc >::operator[] (const key_type & __k) [inline]

Subscript ( [] ) access to map data.

Parameters

__k The key for which data should be retrieved.

Returns

A reference to the data of the (key,data) pair.

Allows for easy lookup with the subscript ( [] ) operator. Returns data associated with the key specified in subscript. If the key does not exist, a pair with that key is created using default values, which is then returned.

Lookup requires logarithmic time.

Definition at line 490 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_reverse_iterator std::map< _Key, _Tp, _Compare, _Alloc >::rbegin () const [inline], [noexcept]

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

Definition at line 399 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> reverse_iterator std::map< _Key, _Tp, _Compare, _Alloc >::rbegin () [inline], [noexcept]

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

Definition at line 390 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_reverse_iterator std::map< _Key, _Tp, _Compare, _Alloc >::rend () const [inline], [noexcept]

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

Definition at line 417 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> reverse_iterator std::map< _Key, _Tp, _Compare, _Alloc >::rend () [inline], [noexcept]

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

Definition at line 408 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> size_type std::map< _Key, _Tp, _Compare, _Alloc >::size () const [inline], [noexcept]

Returns the size of the map.

Definition at line 468 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> void std::map< _Key, _Tp, _Compare, _Alloc >::swap (map< _Key, _Tp, _Compare, _Alloc > & __x) [inline], [noexcept]

Swaps data with another map.

Parameters

__x A map of the same element and allocator types.

This exchanges the elements between two maps 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.

Definition at line 1121 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::upper_bound (const _Kt & __x) -> decltype(iterator(_M_t._M_upper_bound_tr(__x)))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1308 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _Kt > auto std::map< _Key, _Tp, _Compare, _Alloc >::upper_bound (const _Kt & __x) const -> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))

[inline]"

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Definition at line 1328 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> iterator std::map< _Key, _Tp, _Compare, _Alloc >::upper_bound (const key_type & __x) [inline]

Finds the end of a subsequence matching given key.

Parameters

__x Key of (key, value) pair to be located.

Returns

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

Definition at line 1302 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> const_iterator std::map< _Key, _Tp, _Compare, _Alloc >::upper_bound (const key_type & __x) const [inline]

Finds the end of a subsequence matching given key.

Parameters

__x Key of (key, value) pair to be located.

Returns

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

Definition at line 1322 of file stl_map.h.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> value_compare std::map< _Key, _Tp, _Compare, _Alloc >::value_comp () const [inline]

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

Definition at line 1149 of file stl_map.h.

Friends And Related Function Documentation

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _K1 , typename _T1 , typename _C1 , typename _A1 > bool operator< (const map< _K1, _T1, _C1, _A1 > &, const map< _K1, _T1, _C1, _A1 > &) [friend]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

template<typename _Key , typename _Tp , typename _Compare = std::less<_Key>, typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >> template<typename _K1 , typename _T1 , typename _C1 , typename _A1 > bool operator== (const map< _K1, _T1, _C1, _A1 > &, const map< _K1, _T1, _C1, _A1 > &) [friend]

Attempts to insert a std::pair into the map.

Parameters

__x Pair to be inserted (see std::make_pair for easy creation of pairs).

Returns

A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the map. A map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the map.

Insertion requires logarithmic time.

Author

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