/*
    MultiwayBranch6.java
    CIS 160
    David G. Klick
    2007-09-25
 
    Demonstrates switch statement with fall-through
    (purposefully missing 'break' statements). This
    version takes leap years into account. This version
    also has some basic input error checking.
*/
import java.util.Scanner;

public class MultiwayBranch6 {
    public static void main(String[] args) {
        int days = 0;
        int month = 0;
        int year = 0;
        boolean valid = true;
        Scanner kbd = new Scanner(System.in);
        
        // get month and check for validity
        System.out.print("What month number is it? ");
        month = kbd.nextInt();
        if ( (month < 1) || (month > 12)) {
            System.out.println("Invalid month specified");
            valid = false;
        }

        // get year and check for validity
        if (valid) {
            System.out.print("What year is it? ");
            year = kbd.nextInt();
            if (year < 1900) {
                System.out.println("Year must be 1900 or greater");
                valid = false;
            }
        }
        
        // do number of days in month calculation
        if (valid) {
            switch (month) {
                case  1: 
                case  3: 
                case  5: 
                case  7: 
                case  8: 
                case  10: 
                case  12: 
                    days = 31;
                    break;
                case  4: 
                case  6: 
                case  9: 
                case 11: 
                    days = 30;
                    break;
                case  2:
                    if ( ((year % 4 == 0) && !(year % 100 == 0))
                        || (year % 400 == 0)) {
                            days = 29;
                    } else {
                        days = 28;
                    }
                    break;
                default:
                    // should never get here since we have a previous check
                    System.out.println("*Invalid month specified*");
                    valid = false;
            }
        }
        
        // display results
        if (valid) {
           System.out.print(month + "/" + year + " has " + days + " days");
        }
    }
}