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std::array<T,N>::swap

void swap( array& other ) noexcept(/* see below */);		(since C++11) (until C++20)
constexpr void swap( array& other ) noexcept(/* see below */);		(since C++20)

Exchanges the contents of the container with those of other. Does not cause iterators and references to associate with the other container.

Parameters

other

container to exchange the contents with

Return value

(none).

Exceptions

`noexcept` specification: `noexcept(noexcept(swap(std::declval<T&>(), std::declval<T&>())))` In the expression above, the identifier `swap` is looked up in the same manner as the one used by the C++17 `std::is_nothrow_swappable` trait.	(until C++17)
`noexcept` specification: `noexcept(std::is_nothrow_swappable_v<T>)`	(since C++17)

For zero-sized arrays,

noexcept specification:

noexcept

Complexity

Linear in size of the container.

Example

#include <array>
#include <iostream>
 
template<class Os, class V> Os& operator<<(Os& os, const V& v)
{
    os << '{';
    for (auto i : v)
        os << ' ' << i;
    return os << " } ";
}
 
int main()
{
    std::array<int, 3> a1{1, 2, 3}, a2{4, 5, 6};
 
    auto it1 = a1.begin();
    auto it2 = a2.begin();
    int& ref1 = a1[1];
    int& ref2 = a2[1];
 
    std::cout << a1 << a2 << *it1 << ' ' << *it2 << ' ' << ref1 << ' ' << ref2 << '\n';
    a1.swap(a2);
    std::cout << a1 << a2 << *it1 << ' ' << *it2 << ' ' << ref1 << ' ' << ref2 << '\n';
 
    // Note that after swap iterators and references stay associated with their original
    // array, e.g. `it1` still points to element a1[0], `ref1` still refers to a1[1].
}

Output:

{ 1 2 3 } { 4 5 6 } 1 4 2 5
{ 4 5 6 } { 1 2 3 } 4 1 5 2

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