Namespaces
Variants
Views
Actions

Difference between revisions of "cpp/string/basic string/swap2"

From cppreference.com
< cpp‎ | string‎ | basic string
m (fmt)
m (example analog swap)
Line 48: Line 48:
 
int main()
 
int main()
 
{
 
{
−
     std::string a = "AAAA";
+
     std::string a = "AAA";
−
     std::string b = "BBB";
+
     std::string b = "BBBB";
 +
 +
    std::cout << "Before swap:\n"
 +
                "a = " << a << "\n"
 +
                "b = " << b << "\n\n";
  
−
     std::cout << "before swap" << '\n';
+
     std::swap(a, b);
−
    std::cout << "a: " << a << '\n';
+
−
    std::cout << "b: " << b << '\n';
+
  
−
    std::swap(a,b);
+
     std::cout << "After swap:\n"
−
 
+
                "a = " << a << "\n"
−
     std::cout << "after swap" << '\n';
+
                "b = " << b << '\n';
−
    std::cout << "a: " << a << '\n';
+
−
    std::cout << "b: " << b << '\n';
+
 
}
 
}
  
 
|output=
 
|output=
−
before swap
+
Before swap:
−
a: AAAA
+
a = AAA
−
b: BBB
+
b = BBBB
−
after swap
+
−
a: BBB
+
After swap:
−
b: AAAA
+
a = BBBB
 +
b = AAA
 
}}
 
}}
  

Revision as of 00:10, 3 June 2023

 
C++
 
Strings library
 
std::basic_string
Member functions
(C++23)
Element access
(DR*)
(DR*)
(C++17)
Iterators
(C++11)
(C++11)
(C++11)
(C++11)
Capacity
(DR*)
Modifiers
(C++23)
(DR*)
(C++23)
(C++23)
(C++23)  
Search
Operations
(C++20)
(C++20)
(C++23)
Constants
Non-member functions
swap(std::basic_string)
(C++20)(C++20)
I/O
Comparison
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Numeric conversions
(C++11)(C++11)(C++11)
(C++11)(C++11)
(C++11)(C++11)(C++11)
(C++11)
(C++11)
Literals
(C++14)
Helper classes
(C++11)
Deduction guides (C++17)

 
Defined in header <string>
template< class CharT, class Traits, class Alloc >

void swap( std::basic_string<CharT, Traits, Alloc>& lhs,

           std::basic_string<CharT, Traits, Alloc>& rhs );
 (until C++17)
template< class CharT, class Traits, class Alloc >

void swap( std::basic_string<CharT, Traits, Alloc>& lhs,

           std::basic_string<CharT, Traits, Alloc>& rhs ) noexcept(/* see below */);
 (since C++17)
(until C++20)
template< class CharT, class Traits, class Alloc >

constexpr void
    swap( std::basic_string<CharT, Traits, Alloc>& lhs,

          std::basic_string<CharT, Traits, Alloc>& rhs ) noexcept(/* see below */);
 (since C++20)

Specializes the std::swap algorithm for std::basic_string. Swaps the contents of lhs and rhs.

Equivalent to lhs.swap(rhs).

Contents

Parameters

lhs, rhs - strings whose contents to swap

Return value

(none)

Complexity

Constant.

Exceptions

noexcept specification:  
noexcept(noexcept(lhs.swap(rhs)))
 (since C++17)

Example

Run this code
#include <iostream>
#include <string>
 
int main()
{
    std::string a = "AAA";
    std::string b = "BBBB";
 
    std::cout << "Before swap:\n"
                 "a = " << a << "\n"
                 "b = " << b << "\n\n";
 
    std::swap(a, b);
 
    std::cout << "After swap:\n"
                 "a = " << a << "\n"
                 "b = " << b << '\n';
}

Output: 

Before swap:
a = AAA
b = BBBB
 
After swap:
a = BBBB
b = AAA

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 2064 C++11 non-member swap was noexcept and inconsistent with member swap noexcept removed

See also

 swaps the contents
(public member function) [edit]
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/string/basic_string/swap2&oldid=152737"