二、Java之萬年曆

import java.util.Scanner;

public class index {

    // 每個月的天數

    public static int monthday(int month, int year) {

        if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {

            int[] day = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

            return day[month];

        } else {

            int[] day = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

            return day[month];

        }

    }

    // 月份總天數

    public static int monthdays(int month, int year) {

        int totaldays = 0;

        for (int i = 1; i < month; i++) {

            totaldays = totaldays + monthday(i, year);

        }

        return totaldays;

    }

    // 距離 1900 年的年份總天數

    public static int yeardays(int year){

        int yeardays = 0;

        for (int i = 1900;i<year;i++){

            if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0) {

                yeardays = yeardays+366;

            } else {

                yeardays = yeardays+365;

            }

        }

        System.out.println(year+" 年距離 1900 年的總天數 "+yeardays);

        return yeardays;

    }

    // 輸出日曆

    public static void printCalendar(int month,int year){

        int totaldays = 0;

        if (year > 0) {

            if (month > 0 && month < 13) {

                // 距離 1900 年 1 月 1 日總天數

                totaldays = monthdays(month,year)+yeardays(year);

                System.out.println(year+" 年 "+month+" 月 1 日距離 1900 年的總天數 :"+totaldays);

                System.out.外匯跟單gendan5.comprintln("\n**********"+year+" 年 "+month+" 月的日曆為 **********");

                System.out.println(" 一 \t 二 \t 三 \t 四 \t 五 \t 六 \t 日 \t");

                int week = 1+totaldays%7;

                // 根據 1 日為周幾輸出空格

                for(int i=1;i<week;i++){

                    System.out.print(" \t");

                }

                // 輸入具體日期

                for(int i=1;i<=monthday(month,year);i++){

                    System.out.print(i+"\t");

                    if(week==7){

                        week = 1;// 重置為星期一

                        System.out.println();

                    }else{

                        week++;

                    }

                }

            } else {

                System.out.println(" 輸入的月份不合法！ ");

            }

        } else {

            System.out.println(" 輸入的年份不合法！ ");

        }

    }

    // 主函式

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        System.out.println("*********************** 歡迎使用萬年曆 **************************");

        System.out.println("********* 請選擇你需要進行的操作（輸入進行操作之前的數字） **********");

        System.out.println("********************1. 查詢某年某月的日曆 ************************");

        System.out.println("********************2. 結束操作 *********************************");

        System.out.print("\n 請選擇你需要進行的操作： ");

        int a = scanner.nextInt();

        for (int i=0;i>=0;i++) {

            switch (a) {

                case 1:

                    System.out.print(" 請選擇年份： ");

                    int year = scanner.nextInt();

                    System.out.print(" 請選擇月份： ");

                    int month = scanner.nextInt();

                    printCalendar(month, year);

                    System.out.print("\n 請選擇你需要進行的操作： ");

                    a = scanner.nextInt();

                    break;

                case 2:

                    System.out.println(" 退出程式成功！ ");

                    return;

            }

        }

    }

}