// Code derived from Stroustrup's PPP2 book
// § 9.4.2 Member functions and constructors
//  -and beginning on p 311

// simple D// simple Date:
// guarantee initialization with constructor
// provide some notational convenience
struct Date {
  Date(int y, int m, int d);  // check for valid date and initialize

  void add_day(int n);  // increase the Date by n days

  int y, m, d;  // year, month, day
};

Date::Date(int y, int m, int d) : y{y}, m{m}, d{d} {}

// naive
void Date::add_day(int n) { d += n; }

int main()
{
  // Date my_birthday;          // error: my_birthday not initialized
  Date today{12, 24, 2007};  // oops! run-time error
  Date last{2000, 12, 31};   // OK (colloquial style; that is, prefer this form)

  [[maybe_unused]] Date next = {2014, 2, 14};  // also OK (slightly verbose)

  [[maybe_unused]] Date christmas =
      Date{1976, 12, 24};  // also OK (verbose style)

  // We can now try to use our newly defined variables:

  last.add_day(1);
  // add_day(2);  // error: what date?
}