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std::swap(std::unordered_set)

From cppreference.com
 
 
 
 
Defined in header <unordered_set>
template< class Key, class Hash, class KeyEqual, class Alloc >

void swap( std::unordered_set<Key,Hash,KeyEqual,Alloc>& lhs,

           std::unordered_set<Key,Hash,KeyEqual,Alloc>& rhs );
(since C++11)
(until C++14)
template< class Key, class Hash, class KeyEqual, class Alloc >

void swap( std::unordered_set<Key,Hash,KeyEqual,Alloc>& lhs,

           std::unordered_set<Key,Hash,KeyEqual,Alloc>& rhs ) noexcept(/* see below */);
(since C++14)

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


Contents

[edit] Parameters

lhs, rhs - containers whose contents to swap

[edit] Return value

(none)

[edit] Complexity

Constant.

[edit] Exceptions

noexcept specification:  
noexcept(noexcept(lhs.swap(rhs)))
(since C++14)


[edit] Example

#include <algorithm>
#include <iostream>
#include <unordered_set>
 
int main()
{
    std::unordered_set<int> alice{1, 2, 3};
    std::unordered_set<int> bob{7, 8, 9, 10};
 
    auto print = [](const int& n) { std::cout << " " << n; };
 
    // Print state before swap
    std::cout << "alice:";
    std::for_each(alice.begin(), alice.end(), print);
    std::cout << '\n';
    std::cout << "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';
    std::cout << "bob  :";
    std::for_each(bob.begin(), bob.end(), print);
    std::cout << '\n';
}

Possible output:

alice: 1 2 3
bob  : 7 8 9 10
-- SWAP
alice: 7 8 9 10
bob  : 1 2 3

[edit] See also

swaps the contents
(public member function) [edit]