万年历

 

package com.test2;

import java.util.Scanner;

public class Demo2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        System.out.println("请输入年份:");
        Scanner sc = new Scanner(System.in);
        int years = sc.nextInt();
        Year y = new Year();
        y.weekDay = y.firstWeekDay(years);
        y.year = years;
        System.out.println("\n "+years+"年      ");
        y.showMonth();

    }

}

class Year {
    public static int year, weekDay;

    public boolean isLeapYear(int year) {
        return ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0));
    }

    public int firstWeekDay(int year) {

        long day = year * 365;
        for (int i = 1; i < year; i++) {
            if (isLeapYear(i)) {
                day += 1;
            }
        }
        return (int) (day % 7);
    }

    public int getMonthDay(int month) {
        switch (month) {
        case 1:
        case 3:
        case 5:
        case 7:
        case 8:
        case 10:
        case 12:
            return 31;
        case 4:
        case 6:
        case 9:
        case 11:
            return 30;
        case 2:
            if (isLeapYear(year)) {
                return 29;
            } else {
                return 28;
            }
        default:
            return 0;
        }
    }

    public void showMonth() {
        for (int m = 1; m <= 12; m++) {
            System.out.println(m + "月");
            System.out.println(" Sunday  Monday Tuesday Wednesday Thursday Friday Saturday");
            for (int j = 1; j <= weekDay; j++) {
                System.out.print("        ");
            }
            int monthDay = getMonthDay(m);
            for (int d = 1; d <= monthDay; d++) {
                if (d < 10) {
                    System.out.print("   " + "0" + d + "   ");
                } else {
                    System.out.print("   " + d + "   ");
                }
                weekDay = (weekDay + 1) % 7;
                if (weekDay == 0) {
                    System.out.println();
                }
            }
            System.out.println();
        }

    }
}