# std::get(std::tuple)

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< cpp‎ | utility‎ | tuple

template< std::size_t I, class... Types > typename std::tuple_element <I, tuple<Types...> >::type& get( tuple<Types...>& t ) noexcept; | (1) | (since C++11) (constexpr since C++14)
template< std::size_t I, class... Types > typename std::tuple_element <I, tuple<Types...> >::type&& get( tuple<Types...>&& t ) noexcept; | (2) | (since C++11) (constexpr since C++14)
template< std::size_t I, class... Types > typename std::tuple_element <I, tuple<Types...> >::type const& get( const tuple<Types...>& t ) noexcept; | (3) | (since C++11) (constexpr since C++14)
template< std::size_t I, class... Types > typename std::tuple_element <I, tuple<Types...> >::type const&& get( const tuple<Types...>&& t ) noexcept; | (4) | (since C++11) (constexpr since C++14)
template< class T, class... Types > constexpr T& get(tuple<Types...>& t) noexcept; | (5) | (since C++14)
template< class T, class... Types > constexpr T&& get(tuple<Types...>&& t) noexcept; | (6) | (since C++14)
template< class T, class... Types > constexpr const T& get(const tuple<Types...>& t) noexcept; | (7) | (since C++14)
template< class T, class... Types > constexpr const T&& get(const tuple<Types...>&& t) noexcept; | (8) | (since C++14)

1-4) Extracts the `Ith` element from the tuple. `I` must be an integer value in `[0, sizeof...(Types))`.
5-8) Extracts the element of the tuple `t` whose type is `T`. Fails to compile unless the tuple has exactly one element of that type.

### Parameters

t | - | tuple whose contents to extract

### Return value

A reference to the selected element of `t`.

### 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 2485 | C++11 | there are no overloads for const tuple&& | the overloads are added

### Example

Run this code

    #include <iostream>
    #include <string>
    #include <tuple>

    int main()
    {
        auto t = std::make_tuple(1, "Foo", 3.14);
        // index-based access
        std::cout << "(" << std::get<0>(t) << ", " << std::get<1>(t)
                  << ", " << std::get<2>(t) << ")\n";
        // type-based access
        std::cout << "(" << std::get<int>(t) << ", " << std::get<const char*>(t)
                  << ", " << std::get<double>(t) << ")\n";
        // Note: std::tie and structured binding may also be used to decompose a tuple
    }

Output:

    (1, Foo, 3.14)
    (1, Foo, 3.14)

### See also

std::get(std::array) | accesses an element of an `array` (function template)
std::get(std::pair) (C++11) | accesses an element of a `pair` (function template)
std::get(std::variant) (C++17) | reads the value of the variant given the index or the type (if the type is unique), throws on error (function template)

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