//
// This is example code from Chapter 9.8 "The Date class" of 
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

#include <iostream>

using namespace std;

// file Chrono.h

namespace Chrono {

   //------------------------------------------------------------------------------

   enum class Month {
      jan=1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec
         };


   class Date {
   public:
      class Invalid { };                 // to throw as exception

      Date(int y, Month m, int d);       // check for valid date and initialize
      Date();                            // default constructor
      // the default copy operations are fine

      // non-modifying operations:
      int   day()   const { return d; }
      Month month() const { return m; }
      int   year()  const { return y; }

      // modifying operations:
      void add_day(int n);        
      void add_month(int n);
      void add_year(int n);
   private:
      int   y;
      Month m;
      int   d;
   };

   //------------------------------------------------------------------------------

   bool is_date(int y, Month m, int d); // true for valid date

   //------------------------------------------------------------------------------

   bool leapyear(int y);                  // true if y is a leap year

   //------------------------------------------------------------------------------

   bool operator==(const Date& a, const Date& b);
   bool operator!=(const Date& a, const Date& b);

   //------------------------------------------------------------------------------

   ostream& operator<<(ostream& os, const Date& d);
   istream& operator>>(istream& is, Date& dd);

   //------------------------------------------------------------------------------

} // Chrono