NAME

std::basic_string::swap - std::basic_string::swap

Synopsis

void swap( basic_string& other ); (until C++17)
void swap( basic_string& other ) noexcept(/* see below */); (since C++17)
(until C++20)
constexpr void swap( basic_string& other ) noexcept(/* see below */); (since C++20)

Exchanges the contents of the string with those of other. All iterators and
references may be invalidated.

The behavior is undefined if Allocator does not propagate on swap and (since C++11)
the allocators of *this and other are unequal.

Parameters

other - string to exchange the contents with

Return value

(none)

Complexity

Constant.

Exceptions

(since
noexcept specification: C++17)
noexcept(std::allocator_traits<Allocator>::propagate_on_container_swap::value
|| std::allocator_traits<Allocator>::is_always_equal::value)

Example

// Run this code

#include <string>
#include <iostream>

int main()
{
std::string a = "AAA";
std::string b = "BBB";

std::cout << "before swap" << '\n';
std::cout << "a: " << a << '\n';
std::cout << "b: " << b << '\n';

a.swap(b);

std::cout << "after swap" << '\n';
std::cout << "a: " << a << '\n';
std::cout << "b: " << b << '\n';
}

Output:

before swap
a: AAA
b: BBB
after swap
a: BBB
b: AAA