Create std::tuple of types “contained” in another std::tuple

Question

I have a std::tuple created from a variadic template function

std::tuple<Args&...> mytup(args...);

Each object in args has defined a type value_type .

Now, I want to create a std::tuple called mynewtup of the same length of mytup but of types the different types value_type . Moreover, each args has a method f() which return a value_type and mynewtup need to be created calling that function.

In other words, I would like to do something like (pseudocode)

std::tuple<typename args1::value_type,....> mynewtup(args1.f(),....);

Is it possible to do that? How?

Answer 1

只需使用std::make_tuple如下所示：

auto mynewtup = std::make_tuple(args.f()...);