stack class using a templace vector class overloading [] problem

I have built a vector template class and I am now building a stack class that uses the vector class.

When I overload the [] operator I am getting a cannot convert int to vector <T> c2440
definiton of {} are

      Vector<T> & operator[](int index);
      const Vector<T> & operator[](int index) const;

func is
template<typename T>Vector<T> & Vector<T>::operator[](int index) // Returns an object at location index without bounds checking
{
      return vec_array[index];
}

template<typename T>const Vector<T> & Vector<T>::operator[](int index) const // Returns an object at location index without bounds checking
{
      return vec_array[index];
}

Stack is
template <class T>
class stack: Vector <T>
{
  private:
      Vector<T> stack_array;

instantiated using

 stack<int> Stack1;