Defining element initialization order when constructing std::tuple

Question

I would like to store the initialization values for elements in a tuple inside a separate tuple, so that I can use the same values as a preset for other tuples of the respective

Answer 1

There is no requirement in the standard for the order of std::tuple member initialisation, I am afraid.

You can iterate over a tuple in a specific order though, e.g.:

#include 
#include 

#include 
#include 

int main()
{
    auto a = std::make_tuple(true, 42, 3.14, "abc");
    boost::fusion::for_each(a, [](auto& value) {
            std::cout << value << '\n';
        });
}

Outputs:

1
42
3.14
abc