How can add a "less than" statement into this program - switch-statement

Question

I've been tasked with creating a program using a switch statement to print the month names according to the exact number of days in the month. The program also needs to display an "error" message if the number of days entered does not correspond to any month. My code achieves these two goals. However i am wondering if there is shorter way to get the "error" message using a "less than" statement for when the user enters a number less than 28
import java.util.Scanner;
public class months {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
int numb_days = 0;
System.out.println("Enter the # of days");
numb_days = keyboard.nextInt();
//This program will print 'May' when you run it.
String monthName;
switch (numb_days) {
case 30: monthName = "April, June, September, November ";
break;
case 31: monthName = "January, March, May, July, August, November, October, December ";
break;
case 28: monthName = "February";
break;
case 29: monthName = "February (only on leap years)";
break;
case 1: monthName = "Unknown";
break;
case 2: monthName = "Unknown";
break;
case 3: monthName = "Unknown";
break;
case 4: monthName = "Unknown";
break;
case 5: monthName = "Unknown";
break;
case 6: monthName = "Unknown";
break;
case 7: monthName = "Unknown";
break;
case 8: monthName = "Unknown";
break;
case 9: monthName = "Unknown";
break;
case 10: monthName = "Unknown";
break;
case 11: monthName = "Unknown";
break;
case 12: monthName = "Unknown";
break;
case 13: monthName = "Unknown";
break;
case 14: monthName = "Unknown";
break;
case 15: monthName = "Unknown";
break;
case 16: monthName = "Unknown";
break;
case 17: monthName = "Unknown";
break;
case 18: monthName = "Unknown";
break;
case 19: monthName = "Unknown";
break;
case 20: monthName = "Unknown";
break;
case 21: monthName = "Unknown";
break;
case 22: monthName = "Unknown";
break;
case 23: monthName = "Unknown";
break;
case 24: monthName = "Unknown";
break;
case 25: monthName = "Unknown";
break;
case 26: monthName = "Unknown";
break;
case 27: monthName = "Unknown";
break;
default: monthName = "Unknown";
break;
}
System.out.println(monthName);
}
}

Answer 1

The default statement is sufficient for handling all other cases that aren't caught by the specific cases for 28-31. So you can remove all other cases 1-27.
If you are required to use a less than statement you can use it before using the switch statement:
if (numb_days < 28) {
month_name = "unknown";
} else {
// Switch statement goes here
}