// Class-Definitionen:

class Func
{   static double Dummy;
  public:
    virtual double eval(double) = 0;
    virtual void print(char*) = 0;
    virtual ~Func();
    virtual int isconst(double &val = Dummy);
};

class KonstN: public Func
{  double Konst;
  public:
   double eval(double)
     { return Konst; }
   int isconst(double &);
   KonstN(double);
   void print(char*);
};

class VarN: public Func
{ public:
    double eval(double x)
      { return x; }
    void print(char*);
};

class ErrorN: public Func
{ public:
    double eval(double)
      { return 1; }
    void print(char*);
};

enum UnOps { Op_neg, Op_sqr, Op_sqrt, Op_sin, Op_cos, Op_exp, Op_ln};

enum BinOps { Op_add, Op_sub, Op_mult, Op_div, Op_pot };

class UnOpN: public Func
{  UnOps oper;
   Func *arg;
  public:
   double eval(double);
   UnOpN(UnOps, Func*);
   void print(char*);
   ~UnOpN();
};

class BinOpN: public Func
{  BinOps oper;
   Func *l, *r;
  public:
   double eval(double);
   BinOpN(BinOps, Func*, Func*);
   void print(char*);
   ~BinOpN();
};

Func *Parse(char*);