Use Enum Instead of Hard-Coded Numbers

Do

enum Months { 
  January = 1, 
  February = 2, 
  March = 3, 
  April = 4, 
  May = 5, 
  June = 6, 
  July = 7, 
  August = 8, 
  September = 9, 
  October = 10, 
  November = 11,
  December = 12 
} 

if((Months)month == Months.February) { 
  days = 28; 
}

Don't

if(month == 2) { 
  days = 28; 
}