19. Adding a range of values to a container

Writing functions with any number of arguments is possible using variadic function templates. The function should have the container as the first parameter, followed by a variable number of arguments representing the values to be added at the back of the container. However, writing such a function template can be significantly simplified using fold expressions. Such an implementation is shown here:

template<typename C, typename... Args>
void push_back(C& c, Args&&... args)
{
   (c.push_back(args), ...);
}

Examples of using this function template, with various container types, can be seen in the following listing:

int main()
{
   std::vector<int> v;
   push_back(v, 1, 2, 3, 4);
   std::copy(std::begin(v), std::end(v), 
             std::ostream_iterator<int>(std::cout, " "));

   std::list<int> l;
   push_back(l, 1, 2, 3, 4);
   std::copy(std::begin(l), std::end(l), 
             std::ostream_iterator<int>(std::cout, " "));
}