Java Program to Check if a Year is a Leap Year

1. Introduction

Determining whether a year is a leap year is a common task in programming. A leap year occurs every 4 years to add an extra day to the calendar year, helping to keep our calendar in alignment with the Earth's revolutions around the Sun. However, simply being divisible by 4 does not guarantee that a year is a leap year. This blog post explains how to implement a Java program to check if a given year is a leap year, considering all the rules.

2. Program Steps

1. Import the Scanner class to read the year input from the user.

2. Prompt the user to enter a year.

3. Apply the leap year conditions to determine if the year is a leap year.

4. Display the result.

5. Close the Scanner object to prevent resource leaks.

3. Code Program

import java.util.Scanner;

public class LeapYearChecker {
    public static void main(String[] args) {
        // Create a Scanner object for reading input
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter a year:");
        int year = scanner.nextInt(); // Read the year entered by the user

        // Closing the scanner
        scanner.close();

        // Leap year conditions
        if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
            System.out.println(year + " is a leap year.");
        } else {
            System.out.println(year + " is not a leap year.");
        }
    }
}

Output:

Enter a year:
2000
2000 is a leap year.

Explanation:

1. The program starts by importing the Scanner class for reading user input.

2. It prompts the user to enter a year, which is read from the console and stored in the year variable.

3. To determine if the year is a leap year, the program applies the following conditions: A year is a leap year if it is divisible by 4 but not by 100, except if it is also divisible by 400. This is implemented using an if-else statement that checks these conditions.

4. Depending on the outcome of the condition check, the program prints a message indicating whether the entered year is a leap year or not.

5. Lastly, the Scanner object is closed to avoid resource leaks. This program effectively demonstrates the use of conditional statements in Java to solve a problem based on specific rules.