BUPT JAVA: 打印日历

打印日历

题目描述:

请按要求打印日历

输入:

只有一行, 为两个用空格分隔的整数, 第一个代表年份 (大于等于 1900 且小于等于 3000), 第二个代表月份 (保证在 1 到 12 之间).

输出:

该月的月历, 具体格式见样例.
注意: 输出中每一列都是 4 个字符, 如果不足 4 个则前边用空格填补. 第一列也是.

输入样例:

2021 4

输出样例:

Mon Tue Wed Thu Fri Sat Sun
              1   2   3   4
  5   6   7   8   9  10  11
 12  13  14  15  16  17  18
 19  20  21  22  23  24  25
 26  27  28  29  30

Java

// 2023/04/03
// 打印日历
import java.util.*;

public class Main {
    public static void main(String[] args) {

        var input = new Scanner(System.in);
        int year = input.nextInt(), month = input.nextInt();
        month--; // 注意, 输入的 month 值和 Java 默认的 month 值差一
        // 设置日历的年月日, 主要月份是从 (0 ~ 11)
        var calendar = new GregorianCalendar(year, month, 1);

        // 定义一周的起始星期
        int firstDayOfWeek = GregorianCalendar.MONDAY;
        calendar.setFirstDayOfWeek(Calendar.MONDAY);

        // 获取这个月 1 号是星期几, (周日: 1 --- 周六: 7 )
        int weekday = calendar.get(Calendar.DAY_OF_WEEK);

        // 确定第一行的缩进
        int indent = (weekday >= firstDayOfWeek) ? (weekday - firstDayOfWeek) : 6;

        String[] weekdayNames = new String[]{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
        for (String weekdayName : weekdayNames)
            System.out.printf("%4s", weekdayName);
        System.out.println();

        for (int i = 1; i <= indent; i++)
            System.out.print("    " );

        do {
            int day = calendar.get(Calendar.DAY_OF_MONTH);
            System.out.printf("%4d", day);

            // 日期后移
            calendar.add(Calendar.DAY_OF_MONTH, 1);
            weekday = calendar.get(Calendar.DAY_OF_WEEK);

            // 又到了一周的开始, 开启下一行
            if (weekday == firstDayOfWeek)
                System.out.println();
        }
        while (calendar.get(Calendar.MONTH) == month);

        if (weekday != firstDayOfWeek)
            System.out.println();
    }
}

2023-04-03 
IP属地: 北京