import java.util.*; public class Date { private int year; private int month; private int day; public Date(int year, int month, int day) { this.year = year; this.month = month; this.day = day; } public int getDayOfYear() { int[] daysOfMonth = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; int dayOfYear = daysOfMonth[month - 1] + day; if (isLeapYear() && month > 2) { dayOfYear++; } return dayOfYear; } public boolean isLeapYear() { if (year % 4 == 0) { if (year % 100 == 0) { return year % 400 == 0; } else { return true; } } else { return false; } } public static void main(String[] args) { Scanner scan = new Scanner(System.in); int year = scan.nextInt(); int month = scan.nextInt(); int day = scan.nextInt(); Date date = new Date(year, month, day); System.out.println(date.getDayOfYear()); } }报错：Main.java:3: error: class Date is public, should be declared in a file named Date.java public class Date { ^ 1 error，修改代码

你需要将 `Date` 类保存到一个名为 `Date.java` 的文件中，并在 `Main.java` 中使用它。在 `Main.java` 文件中，你可以使用 `import` 语句来导入 `Date` 类。

下面是修改后的代码：

Date.java 文件：

public class Date {
    private int year;
    private int month;
    private int day;

    public Date(int year, int month, int day) {
        this.year = year;
        this.month = month;
        this.day = day;
    }

    public int getDayOfYear() {
        int[] daysOfMonth = {
            0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
        };
        int dayOfYear = daysOfMonth[month - 1] + day;
        if (isLeapYear() && month > 2) {
            dayOfYear++;
        }
        return dayOfYear;
    }

    public boolean isLeapYear() {
        if (year % 4 == 0) {
            if (year % 100 == 0) {
                return year % 400 == 0;
            } else {
                return true;
            }
        } else {
            return false;
        }
    }
}

Main.java 文件：

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int year = scan.nextInt();
        int month = scan.nextInt();
        int day = scan.nextInt();
        Date date = new Date(year, month, day);
        System.out.println(date.getDayOfYear());
    }
}