class Stac {
  // default is private access
  static int MAXVAL;    // maximum size of stack
  int _sp;              // next free stack position
  double *_val;         // value stack
  
 public:
  Stac();
  Stac(int);
  Stac(const Stac&);
  ~Stac(void);
  
  void push(double f);
  double pop(void);
  void maxval(int max);
  void maxval(void);
};