java - 我的代码有什么问题吗？泽勒同余算法代码

Question

我的代码有什么问题吗？出于某种原因，我总是把休息日推迟一天？例如，今天是 2013 年 26 号，是星期二，但程序告诉我今天是星期三。我正在使用 Zeller 的同余算法。

import javax.swing.JOptionPane;
public class zeller {
    public static void main(String[] args) {
        String yearString = JOptionPane.showInputDialog("Enter the year:");

        int year = Integer.parseInt(yearString);

        String monthString = JOptionPane.showInputDialog("Enter the month (3-12)(January and Feburary are 13 and 14):");
        int month = Integer.parseInt(monthString);

        String dayString = JOptionPane.showInputDialog("Enter the day 1-31: ");  
        int day = Integer.parseInt(dayString);

        switch (month) {
            case 13:  monthString = "January";
                break;
            case 14:  monthString = "February";
                break;
            case 3:  monthString = "March";
                break;
            case 4:  monthString = "April";
                break;
            case 5:  monthString = "May";
                break;
            case 6:  monthString = "June";
                break;
            case 7:  monthString = "July";
                break;
            case 8:  monthString = "August";
                break;
            case 9:  monthString = "September";
                break;
            case 10: monthString = "October";
                break;
            case 11: monthString = "November";
                break;
            case 12: monthString = "December";
                break;
            default: monthString = "Invalid month";
                break;
        }

        int j = year / 100;
        int k = year % 100 ;
        double h = (day + ((26*(month + 1)) / 10) + k + (k / 4) +(j / 4) + (5 * j)) % 7;
        int h1 = (int)h;

        switch (h1) {
            case 0:  dayString = "Saturday";
                break;
            case 1:  dayString = "Sunday";
                break;
            case 2:  dayString = "Monday";
                break;
            case 3:  dayString = "Tuesday";
                break;
            case 4:  dayString = "Wednesday";
                break;
            case 5:  dayString = "Thursday";
                break;
            case 6:  dayString = "Friday";
                break;

            default: monthString = "Invalid month";
                break;
        }

        System.out.println("Day of the week is: " + dayString);
    }
}

Answer 1

1. 1 月和 2 月分别算作上一年的第 13 个月和第 14 个月，因此如果您希望用户输入一月或二月的实际月份 1 或 2，您可以添加如下代码:

if (month == 1 ){
    month = 13;
     year -=1;
 }
else if (month == 2) {
     month = 14;
     year -=1;
}