std::swap(std::multimap)

 

C++

Compiler support

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Feature test macros (C++20)

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Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

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Iterator invalidation

Member function table

Non-member function table

 

std::multimap

Member functions

multimap::multimap

multimap::~multimap

multimap::operator=

multimap::get_allocator

Iterators

multimap::beginmultimap::cbegin (C++11)

multimap::endmultimap::cend (C++11)

multimap::rbeginmultimap::crbegin (C++11)

multimap::rendmultimap::crend (C++11)

Capacity

multimap::empty

multimap::size

multimap::max_size

Modifiers

multimap::clear

multimap::insert

multimap::insert_range (C++23)

multimap::emplace (C++11)

multimap::emplace_hint (C++11)

multimap::erase

multimap::swap

multimap::extract (C++17)

multimap::merge (C++17)

Lookup

multimap::count

multimap::find

multimap::contains (C++20)

multimap::equal_range

multimap::lower_bound

multimap::upper_bound

Observers

multimap::key_comp

multimap::value_comp

Non-member functions

std::swap

erase_if (C++20)

operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Deduction guides(C++17)

 

Defined in header <map>
template< class Key, class T, class Compare, class Alloc > void swap( std::multimap<Key, T, Compare, Alloc>& lhs,            std::multimap<Key, T, Compare, Alloc>& rhs );		(until C++17)
template< class Key, class T, class Compare, class Alloc > void swap( std::multimap<Key, T, Compare, Alloc>& lhs,            std::multimap<Key, T, Compare, Alloc>& rhs ) noexcept(/* see below */);		(since C++17)

Specializes the std::swap algorithm for std::multimap. Swaps the contents of lhs and rhs. Calls lhs.swap(rhs).

Parameters

lhs, rhs

-

containers whose contents to swap

Return value

(none)

Complexity

Constant.

Exceptions

noexcept specification:   noexcept(noexcept(lhs.swap(rhs)))

(since C++17)

Notes

Although the overloads of std::swap for container adaptors are introduced in C++11, container adaptors can already be swapped by std::swap in C++98. Such calls to std::swap usually have linear time complexity, but better complexity may be provided.

Example

Run this code

#include <algorithm>
#include <iostream>
#include <map>
 
int main()
{
    std::multimap<int, char> alice{{1, 'a'}, {2, 'b'}, {3, 'c'}};
    std::multimap<int, char> bob{{7, 'Z'}, {8, 'Y'}, {9, 'X'}, {10, 'W'}};
 
    auto print = [](std::pair<const int, char>& n) { 
        std::cout << " " << n.first << '(' << n.second << ')'; 
    };
 
    // Print state before swap
    std::cout << "alice:";
    std::for_each(alice.begin(), alice.end(), print);
    std::cout << "\n" "bob  :";
    std::for_each(bob.begin(), bob.end(), print);
    std::cout << '\n';
 
    std::cout << "-- SWAP\n";
    std::swap(alice, bob);
 
    // Print state after swap
    std::cout << "alice:";
    std::for_each(alice.begin(), alice.end(), print);
    std::cout << "\n" "bob  :";
    std::for_each(bob.begin(), bob.end(), print);
    std::cout << '\n';
}

Output:

alice: 1(a) 2(b) 3(c)
bob  : 7(Z) 8(Y) 9(X) 10(W)
-- SWAP
alice: 7(Z) 8(Y) 9(X) 10(W)
bob  : 1(a) 2(b) 3(c)

See also

swap	swaps the contents (public member function)