std::experimental::ranges::exchange

< cpp‎ | experimental‎ | ranges
template< MoveConstructible T, class U = T >

    requires Assignable<T&, U>

constexpr T exchange(T& obj, U&& new_val) noexcept(/* see below */);
 (ranges TS)

Replaces the value of obj with new_value and returns the old value of obj, as if by

T old_value = std::move(obj);
obj = std::forward<U>(new_value);
return old_value;

Parameters

obj - object whose value to replace
new_value - the value to assign to obj

Return value

The old value of obj

Exceptions

noexcept specification:  
noexcept(std::is_nothrow_move_constructible<T>::value &&
         std::is_nothrow_assignable<T&, U>::value)

Example

This section is incomplete
Reason: no example

See also

(C++14)
 replaces the argument with a new value and returns its previous value
(function template)