generic iterators to access elements of vectors without using Templates c++

I am creating a function which should take as input iterators to vector for example:

vector<int> a;
foo(a.begin(),a.end())

The vector can hold any type.

Now the simple way to do this is using templates

template <typename Iterator>
void foo(Iterator first, Iterator last) {
    for (Iterator it = first; it!=last; ++it) {
        cout << *it;
    }
}

I want to know if there is a way to achieve the same functionality without using templates. Since using Templates would force me to include these functions in Header file of a public API which I don't want to. So I wanted to know is there an alternate way to access the iterators without using Templates.