Example: DaysInMonth in Java

// DaysInMonth
import java.util.Scanner;

// Main class containing the entry point of the program
public class Main {
    public static void main(String[] args) {
        // Step 1: Create a Scanner object to read user input
        Scanner scanner = new Scanner(System.in);

        // Step 2: Prompt the user to enter the month (1-12)
        System.out.print("Enter the month (1-12): ");
        int month = scanner.nextInt();

        // Step 3: Prompt the user to enter the year
        System.out.print("Enter the year: ");
        int year = scanner.nextInt();

        // Step 4: Declare a variable to store the number of days
        int numberOfDays = 0;

        // Step 5: Use a switch statement to determine days based on month
        switch (month) {
            case 1: // January
            case 3: // March
            case 5: // May
            case 7: // July
            case 8: // August
            case 10: // October
            case 12: // December
                numberOfDays = 31;
                break;
            case 4: // April
            case 6: // June
            case 9: // September
            case 11: // November
                numberOfDays = 30;
                break;
            case 2: // February
                // Check for leap year
                if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
                    numberOfDays = 29; // Leap year
                } else {
                    numberOfDays = 28; // Common year
                }
                break;
            default:
                System.out.println("Invalid month entered.");
                return; // Exit the program if month is invalid
        }

        // Step 6: Display the result
        if (numberOfDays != 0) {
            System.out.println("Number of days in " + getMonthName(month) + " " + year + ": " + numberOfDays);
        }

        // Step 7: Close the scanner
        scanner.close();
    }

    // Helper method to get month name (optional, for better output)
    public static String getMonthName(int month) {
        String[] monthNames = {"", "January", "February", "March", "April", "May", "June",
                               "July", "August", "September", "October", "November", "December"};
        if (month >= 1 && month <= 12) {
            return monthNames[month];
        }
        return "Invalid Month";
    }
}