std::pair<T1,T2>::swap
From cppreference.com
void swap(pair& other) noexcept(/* see below */); |
(since C++11) (until C++20) |
|
constexpr void swap(pair& other) noexcept(/* see below */); |
(since C++20) | |
Swaps first
with other.first
and second
with other.second
.
Parameters
other | - | pair of values to swap |
Return value
(none)
Exceptions
noexcept specification:
noexcept( noexcept(swap(first, other.first)) && In the expression above, the identifier |
(until C++17) |
noexcept specification:
noexcept( std::is_nothrow_swappable_v<first_type> && |
(since C++17) |
Example
Run this code
#include <iostream> #include <utility> #include <string> int main() { std::pair<int, std::string> p1, p2; p1 = std::make_pair(10, "test"); p2.swap(p1); std::cout << "(" << p2.first << ", " << p2.second << ")\n"; }
Output:
(10, test)
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 2456 | C++11 | the noexcept specification is ill-formed
|
made to work |
See also
swaps the values of two objects (function template) |