Stefan Röttger

struct Date
{
   int day, month, year;
};

Date date = {1, 1, 2004};

date.year=2000;
date.month=13; -> inconsistent date

class Date
{
   public:

   Date()
   {
      day_=1;
      month_=1;
      year_=0;
   }

   Date(int day,int month,int year)
   {
      day_=day;
      month_=month;
      year_=year;
   }

   void get(int &day, int &month, int &year)
   {
      day=day_;
      month=month_;
      year=year_;
   }

   void set(const int &day, const int &month, const int &year)
   {
      if (day<1 || day>31) throw std::invalid_argument("invalid day")
      if (month<1 || month>12) throw std::invalid_argument("invalid month")

      day_=day;
      month_=month;
      year_=year;
   }

   bool isleapyear()
   {
      return((year_%4==0 && year_%100!=0) || year_%400==0);
   }

   protected:

   int day_, month_, year_;
};

Date date(1, 1, 2004);

date.year_=2000; -> compiler error due to access of protected member variable
date.set(1,13,2000); -> run time error due to uncatched exception

date.set(1,1,2000);
date.isleapyear() -> false;