std::swap(std::queue)
From cppreference.com
| Defined in header <queue>
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template< class T, class Container > void swap( std::queue<T, Container>& lhs, std::queue<T, Container>& rhs ); |
(since C++11) (until C++17) |
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template< class T, class Container > void swap( std::queue<T, Container>& lhs, std::queue<T, Container>& rhs ) noexcept(/* see below */); |
(since C++17) | |
Specializes the std::swap algorithm for std::queue. Swaps the contents of lhs and rhs. Calls lhs.swap(rhs).
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This overload participates in overload resolution only if |
(since C++17) |
Parameters
| lhs, rhs | - | containers whose contents to swap |
Return value
(none)
Complexity
Same as swapping the underlying containers.
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 <queue>
int main()
{
std::queue<int> alice;
std::queue<int> bob;
auto print = [](const auto& title, const auto& cont)
{
std::cout << title << " size=" << cont.size();
std::cout << " front=" << cont.front();
std::cout << " back=" << cont.back() << '\n';
};
for (int i = 1; i < 4; ++i)
alice.push(i);
for (int i = 7; i < 11; ++i)
bob.push(i);
// Print state before swap
print("Alice:", alice);
print("Bobby:", bob);
std::cout << "-- SWAP\n";
std::swap(alice, bob);
// Print state after swap
print("Alice:", alice);
print("Bobby:", bob);
}
Output:
Alice: size=3 front=1 back=3
Bobby: size=4 front=7 back=10
-- SWAP
Alice: size=4 front=7 back=10
Bobby: size=3 front=1 back=3
See also
(C++11) |
swaps the contents (public member function) |