std::basic_string<CharT,Traits,Allocator>::swap (3) - Linux Manuals

std::basic_string<CharT,Traits,Allocator>::swap: std::basic_string<CharT,Traits,Allocator>::swap

NAME

std::basic_string<CharT,Traits,Allocator>::swap - std::basic_string<CharT,Traits,Allocator>::swap

Synopsis

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

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 the allocators of *this and other are unequal. (since C++11)

Parameters

other - string to exchange the contents with

Return value

(none)

Exceptions

                                                                              (since C++17)
noexcept specification:
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

Complexity

Constant.