#include <stdio.h>

// 判断闰年
int isLeapYear(int year) {
    return ((year % 4 == 0 && year % 100!= 0) || year % 400 == 0);
}

// 计算给定日期是周几（蔡氏公式）
int dayOfWeek(int year, int month, int day) 
{
    if (month < 3) {
        year--;
        month += 12;
    }
    int c = year / 100;
    int y = year % 100;
    int d = (day + (13 * (month + 1) / 5) + y + (y / 4) + (c / 4) + (5 * c)) % 7;
    return d;
}

// 输出单列日历
void printSingleColumnCalendar(int year) {//printSingleColumnCalendar打印单个月日历空间
    char *months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
    int daysInMonth[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};//储存一年每月的天数
    if (isLeapYear(year)) {
        daysInMonth[1] = 29;//特殊年份
    }
    for (int m = 0; m < 12; m++) {//输出一年的月份
        printf("%s %d\n", months[m], year);
        printf("Sun Mon Tue Wed Thu Fri Sat\n");
        int weekDay = dayOfWeek(year, m + 1, 1);
        for (int i = 0; i < weekDay; i++) {
            printf("    ");
        }
        for (int d = 1; d <= daysInMonth[m]; d++) {
            printf("%3d ", d);
            if ((weekDay + d) % 7 == 0) {
                printf("\n");
            }
        }
        printf("\n\n");
    }
}

// 输出双列日历
void printDoubleColumnCalendar(int year) {//printDoubleColumnCalendar打印并排月的日历
    char *months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
    int daysInMonth[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    if (isLeapYear(year)) {
        daysInMonth[1] = 29;
    }
    for (int m = 0; m < 12; m++) {
        printf("%s %d\t\t", months[m], year);
        if (m % 2 == 0) {
            printf("\n");
        }
        printf("Sun Mon Tue Wed Thu Fri Sat\t\tSun Mon Tue Wed Thu Fri Sat\n");
        int weekDay = dayOfWeek(year, m + 1, 1);
        for (int i = 0; i < weekDay; i++) {
            printf("    ");
        }
        for (int d = 1; d <= daysInMonth[m]; d++) {
            printf("%3d ", d);
            if ((weekDay + d) % 7 == 0) {
                printf("\n");
            }
        }
        printf("\n\n");
    }
}

// 菜单显示
void menu() {
    int choice, year,a;
    printf("1.输出对应年份全年的日历：\n");
    printf("2.判断输入年份是否为闰年：\n");
    printf("3.对应日期为周几：\n");
    printf("4.退出：\n");
    scanf("%d",&a);
    if(a==1)
    {
    	printf("1. 输出单列日历\n2. 输出双列日历\n3. 退出\n: ");
    scanf("%d", &choice);
    if (choice == 1 || choice == 2) {
        printf("请输入年份: ");
        scanf("%d", &year);
        if (year < 1900 || year > 2100) {//报错范围
            printf("年份超出范围，请重新输入\n");
            menu();
            return;
        }
        if (choice == 1) {
            printSingleColumnCalendar(year);//选择单列
        } else {
            printDoubleColumnCalendar(year);//选择双列
        }
    } else if (choice == 3) {
        return;
    } else {
        printf("无效选择，请重新选择\n");
        menu();
    }
}
    else if(a==2)
    {
    	printf("请输入年份：\n");
    scanf("%d",&year);
    if((year % 4 == 0 && year % 100!= 0) || year % 400 == 0)
    printf("闰年");
    else
    printf("平年");
	}
    else if(a==3)
    {

    
}
	}


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