# Java Notes

# Leap Year Program

This program reads a year and tells the user if it's a leap year or not. It uses boolean operators instead of if statements, which would also be a perfectly fine solution.

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    // LeapYear.java - Tells whether a give year is leap year or not.
    // Michael Maus, 22 Sept 2004

    import javax.swing.*;

    public class LeapYear {

        //===================================================================== main
        public static void main(String[] args) {
            //... Variables
            String yearStr;    // String version of year before conversion to int.
            int    year;       // year
            String leapResult; // Tell's whether it's a leap year or not.

            //... Input
            yearStr = JOptionPane.showInputDialog(null, "Enter a year.");
            year = Integer.parseInt(yearStr);

            //... Computation and output
            if (isLeapYear(year)) {
                leapResult = " is a leap year";
            } else {
                leapResult = year + " isn't a leap year";
            }

            //... Output
            JOptionPane.showMessageDialog(null, leapResult);

            System.exit(0);  // Stop GUI program
        }

        //=============================================================== isLeapYear
        static boolean isLeapYear(int yr) {
            return (yr%400 == 0) || ((yr%4 == 0) && (yr%100 != 0));
        }
    }