tuple_transform.cpp

template<int N, typename Tupl, typename Op>
struct tuple_transform_impl
{
    static void increment(Tupl& tuple, Op op)
    {
        std::get<N>(tuple) = op(std::get<N>(tuple));
        tuple_transform_impl<N - 1, Tupl, Op>::increment(tuple, op);
    }
};

template<typename Tupl, typename Op>
struct tuple_transform_impl<-1, Tupl, Op>
{
    static void increment(Tupl&, Op) {}
};

template<template<typename...> typename Tupl, typename... Elems, typename Op>
void increment_tuple(Tupl<Elems...>& tuple, Op op)
{
    tuple_transform_impl<sizeof...(Elems) - 1, Tupl<Elems...>, Op>::increment(tuple, op);
}

int main()
{
    auto tuple = std::make_tuple(1, 3, 6, 8);
    auto expected = std::make_tuple(2, 4, 7, 9);
    
    increment_tuple(tuple, [] (auto x) { return x + 1; });
    
    assert(tuple == expected);
}