#ifndef STACK_H_
#define STACK_H_

class Stack
{
public:
  Stack();

  bool empty() const;
  void push(int const&);
  void pop();
  int top() const;
  
private:

  class Element
  {
  public:
    Element(int const& i, Element* n = nullptr);
    
    int data;
    Element* next;
  };

  Element* first;
};

#endif