std::swap(std::pair)
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                    |   Defined in header  <utility>
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| (1) | ||
|  (since C++11)  (until C++20)  | 
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| (since C++20) | ||
| (2) | (since C++23) | |
Swaps the contents of x and y. Equivalent to x.swap(y).
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 1) This overload participates in overload resolution only if std::is_swappable_v<first_type> && std::is_swappable_v<second_type> is true. 
2) This overload participates in overload resolution only if std::is_swappable_v<const first_type> && std::is_swappable_v<const second_type> is true. 
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(since C++17) | 
Parameters
| x, y | - | pairs whose contents to swap | 
Return value
(none)
Exceptions
noexcept specification:  
noexcept(noexcept(x.swap(y)))
See also
|    swaps the values of two objects   (function template)  | |
|    (C++11)  | 
   specializes the std::swap algorithm   (function template)  |