range-based for in c++11

in c++ 11 if we have a set<int> S; we could say:

for (auto i: S)
    cout << i << endl;

but can we force i to be a iterator, I mean write a code that is equivalent to:

for (auto i = S.begin(); i != S.end(); i++)
    cout << (i != s.begin()) ? " " : "" << *i;

or could we do something that we can understand the index of i in the set(or vector)?

and another question is how could we say that don't do this for all elements in S but for first half of them or all of them except the first one.

or when we have a vector<int> V, and want to print its first n values what should we do? I know we can create a new vector but it takes time to copy a vector to a new vector.