Template tuple - calling a function on each element

Question

My question is in the code:

template
struct TupleOfVectors {
  std::tuple...> tuple;

  void do_something_t         


        

Answer 1

Here's one approach which may work well in your case:

template
struct TupleOfVectors {
    std::tuple...> tuple;

    void do_something_to_each_vec()
    {
        // First template parameter is just a dummy.
        do_something_to_each_vec_helper<0,Ts...>();
    }

    template
    void do_something_to_vec()
    {
        auto &vec = std::get(tuple);
        //do something to vec
    }

private:
    // Anchor for the recursion
    template 
    void do_something_to_each_vec_helper() { }

    // Execute the function for each template argument.
    template 
    void do_something_to_each_vec_helper()
    {
        do_something_to_each_vec_helper<0,Args...>();
        do_something_to_vec();
    }
};

The only thing that is a bit messy here is the extra dummy int template parameter to do_something_to_each_vec_helper. It is necessary to make the do_something_to_each_vec_helper still be a template when no arguments remain. If you had another template parameter you wanted to use, you could use it there instead.