How to check whether given year is leap year or not in Java?

Problem Description :

Write a program in Java that checks whether given year is leap year or not with proper validations.

Year is leap year or not?

Concept :

A leap year is a year containing one additional day. Leap year has 366 days. If any year satisfies any one of following two conditions than we can say that year is a leap year.

• It is evenly divisible by 4 but not 100.
• It is evenly divisible by 400.

Examples : 2000,2004, 2008 etc.

Java Program :

	package com.javamultiplex.datetime;
	import java.util.Scanner;
	/**
	*
	* @author Rohit Agarwal
	* @category Date and Time
	* @problem Year is leap year or not?
	*
	*/
	public class LeapYear {
	/*
	* Year is called leap year if.
	* 1) It is evenly divisible by 4 and not by 100.
	* 2) It is evenly divisible by 400.
	*/
	public static void main(String[] args) {
	Scanner input = null;
	try {
	input = new Scanner(System.in);
	System.out.println("Enter year : ");
	String year = input.next();
	if (isValidYear(year)) {
	if (isLeapYear(year)) {
	System.out.println("This is leap year.");
	} else {
	System.out.println("This is not leap year.");
	}
	} else {
	System.out.println("Year should be 4 digit long.");
	}
	} finally {
	if (input != null) {
	input.close();
	}
	}
	}
	private static boolean isValidYear(String year) {
	boolean result = false;
	// Regular expression that matches a String contains 4 digits.
	String pattern = "[0-9]{4}";
	if (year.matches(pattern)) {
	result = true;
	}
	return result;
	}
	private static boolean isLeapYear(String year) {
	boolean result = false;
	// Converting String to int.
	int myYear = Integer.parseInt(year);
	if ((myYear % 4 == 0 && myYear % 100 != 0) || myYear % 400 == 0) {
	result = true;
	}
	return result;
	}
	}

view raw LeapYear.java hosted with ❤ by GitHub

Output :

Case 1 :

Output - Given year is not leap year.

Case 2 :

Output - Given year is leap year.

References :

https://en.wikipedia.org/wiki/Leap_year

https://en.wikipedia.org/wiki/Regular_expression

https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html

Thank you friends, I hope you have clearly understood the solution of this problem. If you have any doubt, suggestion or query please feel free to comment below. You can also discuss this solution in our forum.

Tags : Date and Time problems, Leap year, Solution in Java, String, Regular expressions, if else statement.

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