# std::tuple<Types...>::operator=

From cppreference.com
< cpp‎ | utility‎ | tuple

| (1) |
tuple& operator=( const tuple& other ); |  | (since C++11) (until C++20)
constexpr tuple& operator=( const tuple& other ); |  | (since C++20)
| (2) |
tuple& operator=( tuple&& other ) noexcept(/* see below */); |  | (since C++11) (until C++20)
constexpr tuple& operator=( tuple&& other ) noexcept(/* see below */); |  | (since C++20)
| (3) |
template< class... UTypes > tuple& operator=( const tuple<UTypes...>& other ); |  | (since C++11) (until C++20)
template< class... UTypes > constexpr tuple& operator=( const tuple<UTypes...>& other ); |  | (since C++20)
| (4) |
template< class... UTypes > tuple& operator=( tuple<UTypes...>&& other ); |  | (since C++11) (until C++20)
template< class... UTypes > constexpr tuple& operator=( tuple<UTypes...>&& other ); |  | (since C++20)
| (5) |
template< class U1, class U2 > tuple& operator=( const pair<U1,U2>& p ); |  | (since C++11) (until C++20)
template< class U1, class U2 > constexpr tuple& operator=( const pair<U1,U2>& p ); |  | (since C++20)
| (6) |
template< class U1, class U2 > tuple& operator=( pair<U1,U2>&& p ); |  | (since C++11) (until C++20)
template< class U1, class U2 > constexpr tuple& operator=( pair<U1,U2>&& p ); |  | (since C++20)

Replaces the contents of the tuple with the contents of another tuple or a pair.

1) Copy assignment operator. Assigns each element of other to the corresponding element of *this.

2) Move assignment operator. For all `i`, assigns std::forward <Ti>(get<i>(other)) to get<i>(*this).

3) For all `i`, assigns std::get<i>(other) to std::get<i>(*this).

4) For all `i`, assigns std::forward <Ui>(std::get<i>(other)) to std::get<i>(*this).

5) Assigns p.first to the first element of *this and p.second to the second element of *this.

6) Assigns std::forward <U1>(p.first) to the first element of *this and std::forward <U2>(p.second) to the second element of *this.

The behavior of these functions is undefined unless:

- For (1), std::is_copy_assignable <T_i>::value is true for all `T_i` in `Types`.
- For (2), std::is_move_assignable <T_i>::value is true for all `T_i` in `Types`.
- For (3), sizeof...(UTypes) == sizeof...(Types) and std::is_assignable <T_i&, const U_i&>::value is true for all corresponding pairs of types `T_i` in `Types` and `U_i` in `UTypes`.
- For (4), sizeof...(UTypes) == sizeof...(Types) and std::is_assignable <T_i&, U_i&&>::value is true for all corresponding pairs of types `T_i` in `Types` and `U_i` in `UTypes`.
- For (5), sizeof...(Types) == 2 and std::is_assignable <T_0&, const U1&>::value and std::is_assignable <T_1&, const U2&>::value are both true, where `T_0` and `T_1` are the two types constituting `Types`.
- For (6), sizeof...(Types) == 2 and std::is_assignable <T_0&, U1&&>::value and std::is_assignable <T_1&, U2&&>::value are both true, where `T_0` and `T_1` are the two types constituting `Types`.

(until C++17)

These functions do not participate in overload resolution (or, for the copy assignment operator, is defined as deleted) if any required assignment operation is invalid or if there is a size mismatch. Specifically:

- (1) is defined as deleted unless std::is_copy_assignable <T_i>::value is true for all `T_i` in `Types`.
- (2) does not participate in overload resolution unless std::is_move_assignable <T_i>::value is true for all `T_i` in `Types`.
- (3) does not participate in overload resolution unless sizeof...(UTypes) == sizeof...(Types) and std::is_assignable <T_i&, const U_i&>::value is true for all corresponding pairs of types `T_i` in `Types` and `U_i` in `UTypes`.
- (4) does not participate in overload resolution unless sizeof...(UTypes) == sizeof...(Types) and std::is_assignable <T_i&, U_i&&>::value is true for all corresponding pairs of types `T_i` in `Types` and `U_i` in `UTypes`.
- (5) does not participate in overload resolution unless sizeof...(Types) == 2, std::is_assignable <T_0&, const U1&>::value and std::is_assignable <T_1&, const U2&>::value are both true, where `T_0` and `T_1` are the two types constituting `Types`.
- (6) does not participate in overload resolution unless std::is_assignable <T_0&, U1&&>::value and std::is_assignable <T_1&, U2&&>::value are both true, where `T_0` and `T_1` are the two types constituting `Types`.

(since C++17)

### Parameters

other | - | tuple to replace the contents of this tuple
p | - | pair to replace the contents of this 2-tuple

### Return value

*this

### Exceptions

1) (none)

2)
`noexcept` specification:
noexcept(

is_nothrow_move_assignable<T0>::value &&
is_nothrow_move_assignable<T1>::value &&
is_nothrow_move_assignable<T2>::value &&
...

)

3-6) (none)

### Example

| This section is incomplete Reason: no example

### See also

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/utility/tuple/operator%3D&oldid=107586"