What is a Leap Year?
Leap year is a year, occurring once every four years, that has 366 days including February 29 as an intercalary day.
- Is the year divisible by 4? If no – it’s not a leap year
- If yes – Is the year divisible by 100? If no – it’s a leap year
- If yes – Is the year divisible by 400? If no – it’s not a leap year
- If yes – it’s a leap year
- If yes – Is the year divisible by 400? If no – it’s not a leap year
- If yes – Is the year divisible by 100? If no – it’s a leap year
In this tutorial we will implement this logic and find out year is a Leap year or not?
Let’s get started:
Create class CrunchifyFindLeapYear.java. Just copy and paste below code.
Here there are two different ways we will check if year is a leap year or not?
package crunchify.com.java.tutorials;
import java.util.GregorianCalendar;
/**
* @author Crunchify.com
* Program: In Java how to find if Year is Leap Year or not?
* Two different methods.
*/
public class CrunchifyFindLeapYear {
public static void main(String[] args) {
CrunchifyFindLeapYear crunchifyInstance = new CrunchifyFindLeapYear();
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYear(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYear(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYear(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYear(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYearUsingGregorianCalendar(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYearUsingGregorianCalendar(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYearUsingGregorianCalendar(createRandomIntBetween(1900, 2021)));
crunchifyLog("Is it a leap year?: " + crunchifyInstance.isLeapYearUsingGregorianCalendar(createRandomIntBetween(1900, 2021)));
}
// Simple Crunchify Print Utility
private static void crunchifyLog(String s) {
System.out.println(s);
}
// Generate Random Year between 1900 and 2021
public static int createRandomIntBetween(int start, int end) {
int year = start + (int) Math.round(Math.random() * (end - start));
crunchifyLog("\n==> " + year + "");
return year;
}
// Method-1: Logic to find out if Year is a Leap year or not?
public boolean isLeapYear(int year) {
return (year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0));
}
// Method-2: Logic to find out if Year is a Leap year or not using GregorianCalendar.
public boolean isLeapYearUsingGregorianCalendar(int year) {
// GregorianCalendar is a concrete subclass of Calendar and provides the standard calendar system used by most of the world.
// GregorianCalendar is a hybrid calendar that supports both the Julian and Gregorian calendar systems with the support of a single discontinuity,
// which corresponds by default to the Gregorian date when the Gregorian calendar was instituted (October 15, 1582 in some countries, later in others).
// The cutover date may be changed by the caller by calling setGregorianChange().
GregorianCalendar crunchifyDates = (
GregorianCalendar) GregorianCalendar.getInstance();
// isLeapYear(): Determines if the given year is a leap year. Returns true if the given year is a leap year.
// To specify BC year numbers, 1 - year number must be given. For example, year BC 4 is specified as -3.
return crunchifyDates.isLeapYear(year);
}
}
IntelliJ IDEA Result:
Just run above program as Java Application and you will see result as below.
==> 2015 Is it a leap year : false ==> 1936 Is it a leap year : true ==> 1992 Is it a leap year : true ==> 1960 Is it a leap year : true ==> 1949 Is it a leap year : false ==> 1969 Is it a leap year : false ==> 1924 Is it a leap year : true ==> 1926 Is it a leap year : false Process finished with exit code 0
Let me know if you face any issue running above program.
The post In Java how to find if Year is Leap Year or not? Custom logic and GregorianCalendar appeared first on Crunchify.
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