#ifndef CalcFace__SEEN
#define CalcFace__SEEN
///////    File CalcFace.h    ///////
#include <iostream.h>
#include <ctype.h>
// number of significant digits
const int PREC = 6;

// function input: returns op in c and input number if any
//     return value == OPONLY means only op is entered
//     return value == OFF means no more input 

class CalcFace
{   public:
        CalcFace(char* k = "+-*/=NnAaCcQq")
        {  keys = k; }
        int input(char& c, double& number);
        void show_number(double number);
        enum {OPONLY = 1, OFF};
    private:
        int inchar() {  return(cin.get()); }
        void extract_number(double&);
        void build_number(char c, int& i);
        int nump(char c);
        char   nbuf[PREC+2];     // buffer for input number
        char*  keys;             // keys recognized
};

#endif