How do I return hundreds of values from a C++ function?

Question

In C++, whenever a function creates many (hundreds or thousands of) values, I used to have the caller pass an array that my function then fills with the output values:

Answer 1

I'd use something like

std::auto_ptr<std::vector<int> > computeValues(int input);
{
   std::auto_ptr<std::vector<int> > r(new std::vector<int>);
   r->push_back(...) // Hundreds of these
   return r;
}

No copying overhead in the return or risk of leaking (if you use auto_ptr correctly in the caller).

Answer 2

One other option is boost::tuple: http://www.boost.org/doc/libs/1_38_0/libs/tuple/doc/tuple_users_guide.html

int x, y;
boost::tie(x,y) = bar();

Answer 3

I'd say your new solution is more general, and better style. I'm not sure I'd worry too much about style in c++, more about usability and efficiency.

If you're returning a lot of items, and know the size, using a vector would allow you to reserve the memory in one allocation, which may or may not be worth it.