how to return the last type of a variadic template?

Question

For example

template<typename... Ts>
LastTypeOfTs f();

How to return the last type of a variadic template?

Answer 1

You could do a template recursion as below:

template<typename T, typename... Ts>
struct LastTypeOfTs {
   typedef typename LastTypeOfTs<Ts...>::type type;
};

template<typename T>
struct LastTypeOfTs<T> {
  typedef T type;
};

template<typename... Ts>
typename LastTypeOfTs<Ts...>::type f() {
  //...
}

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