From cppreference.com
voidswap(list&other);(until C++17)voidswap(list&other)noexcept(/* see below */);(since C++17)Exchanges the contents of the container with those of other. Does not invoke any move, copy, or swap operations on individual elements.
All iterators and references remain valid. It is unspecified whether an iterator holding the
value in this container will refer to this or the other container after the operation.
If std::allocator_traits<allocator_type>::propagate_on_container_swap::value is true, then the allocators are exchanged using an unqualified call to non-member swap. Otherwise, they are not swapped (and if get_allocator()!=other.get_allocator(), the behavior is undefined).
(since C++11)Parameters
other - container to exchange the contents with Complexity
Constant.
Exceptions
(none)
(until C++17)
specification:
noexcept(std::allocator_traits<Allocator>::is_always_equal::value)(since C++17)Example
Run this code
#include<list>#include<print>intmain(){std::list<int>a1{1,2,3},a2{4,5};autoit1=std::next(a1.begin());autoit2=std::next(a2.begin());int&ref1=*a1.begin();int&ref2=*a2.begin();std::println("{} {} {} {} {} {}",a1,a2,*it1,*it2,ref1,ref2);a1.swap(a2);std::println("{} {} {} {} {} {}",a1,a2,*it1,*it2,ref1,ref2);// Note that after swap the iterators and references stay associated with their// original elements, e.g., it1 that pointed to an element in 'a1' with value 2// still points to the same element, though this element was moved into 'a2'.}Output:
[1, 2, 3] [4, 5] 2 5 1 4 [4, 5] [1, 2, 3] 2 5 1 4 See also