How do you return two values from a single method?

Question

When your in a situation where you need to return two things in a single method, what is the best approach?

I understand the philosophy that a method should do one t

Answer 1

Personally I try to use languages that allow functions to return something more than a simple integer value.

First, you should distinguish what you want: an arbitrary-length return or fixed-length return.

If you want your method to return an arbitrary number of arguments, you should stick to collection returns. Because the collections--whatever your language is--are specifically tied to fulfill such a task.

But sometimes you just need to return two values. How does returning two values--when you're sure it's always two values--differ from returning one value? No way it differs, I say! And modern languages, including perl, ruby, C++, python, ocaml etc allow function to return tuples, either built-in or as a third-party syntactic sugar (yes, I'm talking about boost::tuple). It looks like that:

tuple add_multiply_divide(int a, int b) {
  return make_tuple(a+b, a*b, double(a)/double(b));
}

Specifying an "out parameter", in my opinion, is overused due to the limitations of older languages and paradigms learned those days. But there still are many cases when it's usable (if your method needs to modify an object passed as parameter, that object being not the class that contains a method).

The conclusion is that there's no generic answer--each situation has its own solution. But one common thing there is: it's not violation of any paradigm that function returns several items. That's a language limitation later somehow transferred to human mind.