// Days.java -- A Java program illustrating "case" class Days { private static final int DEFAULT_YEAR = 2021; public static void main (final String[] args) { final int month = Integer.parseInt (args[0]); final int year = args.length>1?Integer.parseInt (args[1]):DEFAULT_YEAR; final int numDays; // Blank final declaration switch (month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: numDays = 31; break; case 4: case 6: case 9: case 11: numDays = 30; break; case 2: if (((year%4==0) && !(year%100==0)) || (year%400==0)) { numDays = 29; } else { numDays = 28; } break; default: numDays = 0; break; } System.out.printf ("Number of days = %d%n", num_days); } }