std::array swap() method
- since C++20
- until C++20
// Non-const version only
constexpr void swap( array& other ) noexcept(/* see below */);
// Non-const version only
void swap( array& other ) noexcept(/* see below */);
The noexcept specification for these two looks like follows:
- until C++17
- since C++17
noexcept(noexcept(swap(std::declval<T&>(), std::declval<T&>())))
noexcept(std::is_nothrow_swappable_v<T>)
Exchanges the contents of the container with those of other.
Parameters
other
- the other array to exchange the contents with
Return value
(none)
Complexity
Linear in the 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].
}
Possible output
{ 1 2 3 } { 4 5 6 } 1 4 2 5
{ 4 5 6 } { 1 2 3 } 4 1 5 2
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