java编写日历打印程序

题目：java编写日历打印程序

实现代码：

package practice;
import java.util.Scanner;
public class MyData {
	
	public static void main(String[] args) {
	      Scanner input = new Scanner(System.in);
	      // Prompt the user to enter year
	      System.out.print("Enter full year (e.g., 2001): ");
	      int year = input.nextInt();
	      // Prompt the user to enter month
	      System.out.print("Enter month in number between 1 and 12: ");
	      int month = input.nextInt();
	      input.close();
	      // Print calendar for the month of the year
	      printMonth(year, month);
	}

	public static void printMonth(int year, int month) {
	      printMonthTitle(year, month);
	      printMonthBody(year, month);
	}

	public static void printMonthTitle(int year, int month) {
	      System.out.println("         " + getMonthName(month) + " " + year);
	      System.out.println("-----------------------------");
	      System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
	}
	
	public static void printMonthBody(int year, int month) {
	      int startDay = getStartDay(year, month);
	      int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);
	      int i = 0;
	      // Pad space before the first day of the month
	      for (i = 0; i < startDay; i++)
	            System.out.print("    ");
	      for (i = 1; i <= numberOfDaysInMonth; i++) {
	            System.out.printf("%4d", i);
	            if ((i + startDay) % 7 == 0)  System.out.println();
	      }
	      System.out.println();
	}

	public static String getMonthName(int month) {
	      String monthName = "";
	      switch (month) { //学习数组后，应将月名字符串存储在数组中，
	            case 1:            //当月份有效时，return names[month-1];
	                  monthName = "January"; break;
	            case 2:
	                  monthName = "February"; break;
	            case 3:
	                  monthName = "March"; break;
	            case 4:
	                  monthName = "April"; break;
	            case 5:
	                  monthName = "May"; break;
	            case 6:
	                  monthName = "June"; break;
	            case 7:
	                  monthName = "July"; break;
	            case 8:
	                  monthName = "August"; break;
	            case 9:
	                  monthName = "September"; break;
	            case 10:
	                  monthName = "October"; break;
	            case 11:
	                  monthName = "November"; break;
	            case 12:
	                  monthName = "December"; break;

	      }
	      return monthName;
	}

	public static int getStartDay(int year, int month) {
	      final int START_DAY_FOR_JAN_1_1800 = 3;
	      // Get total number of days from 1/1/1800 to month/1/year
	      int totalNumberOfDays = getTotalNumberOfDays(year, month);

	      // Return the start day for month/1/year
	      return (totalNumberOfDays + START_DAY_FOR_JAN_1_1800) % 7;
	}

	public static int getTotalNumberOfDays(int year, int month) {
	    int total = 0;
	    // Get the total days from 1800 to 1/1/year
	    for (int i = 1800; i < year; i++)
	        if (isLeapYear(i))
	            total = total + 366;
	        else
	            total = total + 365;
	    // Add days from Jan to the month prior to the calendar month
	    for (int i = 1; i < month; i++)
	          total = total + getNumberOfDaysInMonth(year, i);
	    return total;
	}

	public static int getNumberOfDaysInMonth(int year, int month) {
	    if (month == 1 || month == 3 || month == 5 || month == 7 || 
	        month == 8  || month == 10 || month == 12)
		return 31;
	    if (month == 4 || month == 6 || month == 9 || month == 11)
		return 30;
	    if (month == 2)
		return isLeapYear(year) ? 29 : 28;
	    return 0; // If month is incorrect
	}

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

}

运行截图：