Writing variadic template constructor

Question

Recently I asked this question but now I would like to expand it. I wrote the following class:

template 
class X{
public:
    vector v;
          


        

Answer 1

There is no need for recursion in the first place -
you can use the "temporary array" idiom and write

template 
X(E&&... e) {
    int temp[] = {(v.push_back(e), 0)...};
}

The proper (and more complicated) version of this approach looks like this:

template 
X(E&&... e) {
    (void)std::initializer_list{(v.push_back(std::forward(e)), void(), 0)...};
}

Live version

Note, than the next version of C++ will probably have the Fold Expressions
(v.push_back(e), ...);