std::swap(std::pair) - cppreference.com (original) (raw)
| Defined in header | ||
|---|---|---|
| (1) | ||
| template< class T1, class T2 > void swap( std::pair<T1,T2>& x, std::pair<T1,T2>& y ) noexcept(/* see below */); | (since C++11) (until C++20) | |
| template< class T1, class T2 > constexpr void swap( std::pair<T1,T2>& x, std::pair<T1,T2>& y ) noexcept(/* see below */); | (since C++20) | |
| template< class T1, class T2 > constexpr void swap( const std::pair<T1,T2>& x, const std::pair<T1,T2>& y ) noexcept(/* see below */); | (2) | (since C++23) |
Swaps the contents of x and y. Equivalent to x.swap(y).
[edit] Parameters
| x, y | - | pairs whose contents to swap |
|---|
[edit] Return value
(none)
[edit] Exceptions
specification:
noexcept(noexcept(x.swap(y)))
[edit] Example
#include #include int main() { auto p1 = std::make_pair(10, 3.14); auto p2 = std::pair(12, 1.23); // CTAD, since C++17 auto print_p1_p2 = [&](auto msg) { std::cout << msg << "p1 = {" << std::get<0>(p1) << ", " << std::get<1>(p1) << "}, " << "p2 = {" << std::get<0>(p2) << ", " << std::get<1>(p2) << "}\n"; }; print_p1_p2("Before p1.swap(p2): "); p1.swap(p2); print_p1_p2("After p1.swap(p2): "); std::swap(p1, p2); print_p1_p2("After swap(p1, p2): "); }
Output:
Before p1.swap(p2): p1 = {10, 3.14}, p2 = {12, 1.23} After p1.swap(p2): p1 = {12, 1.23}, p2 = {10, 3.14} After swap(p1, p2): p1 = {10, 3.14}, p2 = {12, 1.23}