#include <stdio.h>
#include <stdlib.h>

// 判断是否为闰年
int isLeapYear(int year) {
    return (year % 4 == 0 && year % 100!= 0) || (year % 400 == 0);
}
// 计算某月有多少天
int daysInMonth(int year, int month) {
    int days[] = {31, 28 + isLeapYear(year), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
     return days[month - 1];
}

// 计算1900年1月1日到给定日期的总天数
int totalDays(int year, int month, int day) {
    int total = 0;
    int y;
    for (y = 1900; y < year; y++) {
        total += 365 + isLeapYear(y);
    }
    int m;
    for (m = 0; m < month; m++) {
        total += daysInMonth(year, m);
    }
    total += day;
    return total;
}

// 打印日历
void printCalendar(int year, int singleColumn) {
    int startDay = (totalDays(year, 1, 1) + 1) % 7;
    printf("Calendar - %d\n", year);
    if (singleColumn) {
    	int month;
        for ( month = 1; month <= 12; month++) {
            int days = daysInMonth(year, month);
            printf("\n\t%d月\n", month);
            printf("\tMon\tTue\tWed\tThu\tFri\tSat\tSun\n");
            int i;
            for (i = 0; i < startDay; i++)
                printf("\t");
                int day;
            for (day = 1; day <= days; day++) {
                printf("\t%d", day);
                if ((startDay + day) % 7 == 0)
                    printf("\n");
            }
            if ((startDay + days) % 7!= 0)
                printf("\n");
            startDay = (startDay + days) % 7;
        }
    } else {
        printf("\tMon\tTue\tWed\tThu\tFri\tSat\tSun\t\tMon\tTue\tWed\tThu\tFri\tSat\tSun\n");
        int month;
        for (month = 1; month <= 12; month++) {
            int days = daysInMonth(year, month);
            int currentStartDay = (totalDays(year, month, 1) + 1) % 7;
            int i;
            for (i = 0; i < currentStartDay; i++)
                printf("\t");
                int day;
            for (day = 1; day <= days; day++) {
                printf("\t%d", day);
                if ((currentStartDay + day) % 7 == 0)
                    printf("\t\t");
            }
            printf("\n");
        }
    }
}

// 查询某日期是周几
void queryDay() {
    int year, month, day;
    printf("请输入日期(年 月 日)：");
    scanf("%d %d %d", &year, &month, &day);
    int total = totalDays(year, month, day);
    int weekDay = (total - 1) % 7;
    char *weekDays[] = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat","Sun"};
    printf("%d年%d月%d日是 %s\n", year, month, day, weekDays[weekDay]);
    printf("该年是 %s年\n", isLeapYear(year)? "闰" : "平");
}

// 菜单
void menu() {
    int choice;
    int year;
    int singleColumn = 1;
    while (1) {
        printf("\n1. 查询某日期是周几并判断是否为闰年\n");
        printf("2. 打印某一年的日历(单列)\n");
        printf("3. 打印某一年的日历(双列)\n");
        printf("4. 退出\n");
        printf("请选择操作：");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                queryDay();
                break;
            case 2:
                printf("请输入年份：");
                scanf("%d", &year);
                printCalendar(year, singleColumn);
                break;
            case 3:
                singleColumn = 0;
                printf("请输入年份：");
                scanf("%d", &year);
                printCalendar(year, singleColumn);
                singleColumn = 1;
                break;
            case 4:
                exit(0);
            default:
                printf("无效的选择，请重新选择\n");
        }
    }
}

int main() {
    menu();
    return 0;
}