Java闰年判断程序无法输出结果，在线课程求助无门求解决

Hey there! Let's break down why your leap year program isn't showing any results—there are two main things going wrong here:

1. You're Missing the Full Implementation of the isLeap Method #

In the code you shared, you call isLeap(year) in your main method, but you never actually wrote what this method does. Without that, your code won't even compile, let alone run and output a result.

2. You're Not Using the Result of isLeap to Output Anything #

Even if you had the isLeap method written, right now you're just calling it and doing nothing with its return value. There's no code to print whether the year is a leap year or not.

Here's the Full, Fixed Code #

I've filled in the missing parts and added the output logic for you:

import java.util.Scanner;
public class LeapYear {
    public static void main(String[] args) {
        displayInstructions();
        int year = getYear();
        // Grab the leap year check result and print it
        boolean isLeapYear = isLeap(year);
        if (isLeapYear) {
            System.out.println(year + " is a leap year!");
        } else {
            System.out.println(year + " is not a leap year.");
        }
    }

    public static void displayInstructions() {
        System.out.println("This program asks you to enter a year as a 4 digit number. The program will tell you if it's a leap year.");
    }

    // You called getYear() but didn't implement it—here's how to get the user's input
    public static int getYear() {
        Scanner inputScanner = new Scanner(System.in);
        System.out.print("Please enter a 4-digit year: ");
        return inputScanner.nextInt();
    }

    // The actual leap year logic, following the standard rules
    public static boolean isLeap(int year) {
        // A year is a leap year if:
        // - It's divisible by 4 but NOT divisible by 100, OR
        // - It's divisible by 400
        return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
    }
}

What Changed? #

• Added the getYear method: You had a call to this method but no code for it—this handles getting the year input from you.
• Implemented the isLeap method: Used the standard leap year rules to correctly check if the year is a leap year.
• Added output logic: After checking if the year is a leap year, the code now prints a clear message telling you the result.

Just replace your existing code with this, run it, and you should see the output you're expecting!

内容的提问来源于stack exchange，提问作者user9579405