stack6decl.hpp

The following code example is taken from the book
C++ Templates - The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, and Douglas Gregor,
Addison-Wesley, 2017
© Copyright David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor 2017


template<typename T>
class Stack {
  private:
    std::deque<T> elems;       // elements

  public:
    void push(T const&);       // push element
    void pop();                // pop element
    T const& top() const;      // return top element
    bool empty() const {       // return whether the stack is empty
        return elems.empty();
    }

    // assign stack of elements of type T2
    template<typename T2>
    Stack& operator= (Stack<T2> const&);
    // to get access to private members of \TStack<T2> for any type T2:
    template<typename> friend class Stack;
};