LeapYears.java

import java.util.Scanner;

public class LeapYears {

    /* Determine whether a particular year is a leap year or not and use this method
     inside a new method to determine a subsequent leap year. */

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        System.out.println("This program calculates leap years.");
        System.out.print("Enter the year: ");
        int year = scan.nextInt();

        if (year<1582) {
            System.out.println("Error! Gregorian Calendar only started in 1582.");
            return;
        } // if

        if (isLeapYear(year)) {
            System.out.println (year +" is a leap year.");
        } else {
            System.out.println (year +" is not a leap year.");
        } // if

        year = findNextLeapYear(year);

        System.out.println ("The next leap year is " + year);

    } // main()

    public static int findNextLeapYear(int year) {
        while (!isLeapYear(++year));
        return year;
    } // findNextLeapYear()

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

} // class LeapYears