const int July = 7;
const int Feb = 2;
int daysInJuly = System.DateTime.DaysInMonth(2001, July);
Console.WriteLine(daysInJuly);
// daysInFeb gets 28 because the year 1998 was not a leap year.
int daysInFeb = System.DateTime.DaysInMonth(1998, Feb);
Console.WriteLine(daysInFeb);
// daysInFebLeap gets 29 because the year 1996 was a leap year.
int daysInFebLeap = System.DateTime.DaysInMonth(1996, Feb);
Console.WriteLine(daysInFebLeap);