template <typename T>
string join(const vector<T> &v, const string &sep)
{
    ostringstream oss;

    for (const T &element: v)
        oss << element << sep;

    const string out = oss.str();

    return v.empty() ?
                out :
                out.substr(0, out.length() - sep.length());
}

// example usage
// cout << join(output, ", ") << endl;
// cout << join(vector<float>(5, 1.1f), ", ") << endl;