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# std::tuple_cat

From cppreference.com
< cpp‎ | utility‎ | tuple

Defined in header `<tuple>` |  |

template< class... Tuples > std::tuple<CTypes...> tuple_cat(Tuples&&... args); |  | (since C++11) (until C++14)
template< class... Tuples > constexpr std::tuple<CTypes...> tuple_cat(Tuples&&... args); |  | (since C++14)

Constructs a tuple that is a concatenation of all tuples in `args`.

### [edit] Parameters

args | - | zero or more tuples to concatenate

### [edit] Return value

A std::tuple object composed of all elements of all argument tuples constructed from std::get<i>(std::forward<Ti>(arg)) for each individual element.

### [edit] Example

Run this code

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

    // helper function to print a tuple of any size
    template<class Tuple, std::size_t N>
    struct TuplePrinter {
        static void print(const Tuple& t)
        {
            TuplePrinter<Tuple, N-1>::print(t);
            std::cout << ", " << std::get<N-1>(t);
        }
    };

    template<class Tuple>
    struct TuplePrinter<Tuple, 1> {
        static void print(const Tuple& t)
        {
            std::cout << std::get<0>(t);
        }
    };

    template<class... Args>
    void print(const std::tuple<Args...>& t)
    {
        std::cout << "(";
        TuplePrinter<decltype(t), sizeof...(Args)>::print(t);
        std::cout << ")\n";
    }
    // end helper function

    int main()
    {
        std::tuple<int, std::string, float> t1(10, "Test", 3.14);
        int n = 7;
        auto t2 = std::tuple_cat(t1, std::make_pair("Foo", "bar"), t1, std::tie(n));
        n = 10;
        print(t2);
    }

Output:

    (10, Test, 3.14, Foo, bar, 10, Test, 3.14, 10)

### [edit] See also

make_tuple | creates a `tuple` object of the type defined by the argument types (function template) [edit]
tie | creates a `tuple` of lvalue references or unpacks a tuple into individual objects (function template) [edit]
forward_as_tuple | creates a `tuple` of rvalue references (function template) [edit]

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