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Introduction to Java

Java Program: Leap Year Check Using Logical Operators

Leap Year Condition

A year is a leap year if:

✅ Uses logical operators: &&, ||, !=

import java.util.Scanner;
 
public class LeapYearCheck {
    public static void main(String[] args) {
 
        Scanner sc = new Scanner(System.in);
 
        System.out.print("Enter a year: ");
        int year = sc.nextInt();
 
        // Leap year condition using logical operators
        boolean isLeap = (year % 400 == 0) ||
                         (year % 4 == 0 && year % 100 != 0);
 
        if (isLeap) {
            System.out.println(year + " is a Leap Year.");
        } else {
            System.out.println(year + " is NOT a Leap Year.");
        }
 
        sc.close();
    }
}
 

 

EXAMPLE 1:

INPUT:
Enter a year: 2024
 
OUTPUT :
2024 is a Leap Year.
 
EXAMPLE 2:

INPUT:
Enter a year: 1900
 
OUTPUT :
1900 is NOT a Leap Year.
 

Explanation

✅ 1. What makes a year a leap year?

A year is a leap year if any of the following is true:

1. Divisible by 400 → Leap year
2. Divisible by 4 but not divisible by 100 → Leap year
3. Else → NOT a leap year

These rules ensure the calendar stays aligned with the earth’s revolution.

✅ 2. Logical Operators Used

• && → AND
• || → OR
• != → NOT equal

The condition:

(year % 400 == 0) || (year % 4 == 0 && year % 100 != 0)

Means:

• If divisible by 400 → leap
• OR
• If divisible by 4 AND NOT divisible by 100 → leap

✅ 3. Why 1900 is not a leap year?

• 1900 % 4 == 0 ✅
• 1900 % 100 == 0 ✅
• 1900 % 400 != 0 ❌

Fails the 400 rule → NOT a leap year.