Chapter 4 Exercise 17, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*4.17 (Days of a month) Write a program that prompts the user to enter a year and the first three letters of a month name (with the first letter in uppercase) and displays the number of days in the month. Here is a sample run:

    Enter a year: 2001
    Enter a month: Jan
    Jan 2001 has 31 days
   
    Enter a year: 2016
    Enter a month: Feb
    Feb 2016 has 29 days

import java.util.Scanner;
 
public class ProgrammingEX4_17 {
 
 public static void main(String[] args) {
 
  Scanner input = new Scanner(System.in);
  System.out.print("Enter a year:");
  int year = input.nextInt();
 
  System.out.print("Enter a month:");
  String month = input.next();
 
  int days = 0;
 
  switch (month) {
  case "Feb":
   if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
    days = 29;
    break;
   }
   days = 28;
   break;
 
  case "Apr":
  case "Jun":
  case "Sep":
  case "Nov":
   days = 30;
   break;
 
  case "Jan":
  case "Mar":
  case "May":
  case "Jul":
  case "Aug":
  case "Oct":
  case "Dec":
   days = 31;
   break;
 
  default:
   System.out.println("Invalid month.");
   System.exit(0);
 
  }
 
  System.out.println(month + " " + year + " has " + days + " days");
 }
}