#include <stdio.h>

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

int getDaysInMonth(int year, int month) 
{
    int daysInMonth[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    if (month == 1 && isLeapYear(year)) 
	{
        return 29;
    }
    return daysInMonth[month];
}

void printCalendarHeader() 
{
    printf("  Sun  Mon  Tue  Wed  Thu  Fri  Sat\n");
}

void printMonth(int year, int month) 
{
	int z;
    int days = getDaysInMonth(year, month);
    int firstDayOfMonth = (year * 365 + (year - 1) / 4 - (year - 1) / 100 + (year - 1) / 400) % 7;
    int i,day;
    for (i = 0; i < month; i++) 
	{
        firstDayOfMonth += getDaysInMonth(year, i);
    }
    firstDayOfMonth %= 7;
    printCalendarHeader();
    for (i = 0; i < firstDayOfMonth; i++) 
	{
        printf("     ");
    }
    for (day = 1; day <= days; day++) 
	{
        printf("%5d", day);
        if ((firstDayOfMonth + day) % 7 == 0) 
		{
            printf("\n");
        }
    }
}

int main(void) 
{
    int choice;
    printf("1. 查询对应年份日历\n");
    printf("2. 查询对应日期星期\n");
    printf("3. 判断所输入年份是否为闰年\n");
    printf("4. 退出\n");
    scanf("%d", &choice);
    int year,month,week,day,day_x,day_z=0,c=0;
    int i,j,k,l,m,n,b;
    char a;
    start:
    switch (choice) 
	{
        case 1:
            printf("请输入年份：");
            scanf("%d", &year);
            int month;
            int z;
            printf("1.单列输出\n2.双列输出\n");
            scanf("%d",&z);
            for (month = 0; month < 12; month++) 
			{
                printf("\n      %d月\n", month + 1);
                printMonth(year, month);
            }
            break;
        case 2:
            printf("请输入该查询的年份：\n");
            scanf("%d",&year);
            printf("请输入该查询的月份：\n");
            scanf("%d",&month);
            printf("请输入该查询的日期: \n");
            scanf("%d",&day);
            if(year<1 || year>9999)
			{
				printf("输入年份错误，请重新输入:");
				scanf("%d",&year);
			}
			if(month<1 || month>12)
			{
				printf("输入月份错误，请重新输入:");
				scanf("%d",&month); 
			}
			if(day<1 || day>31)
			{
				printf("输入日期错误，请重新输入：");
				scanf("%d",&day); 
			}
            if(month<3)
            {
            	year--;
            	month+=12;
			}
			if(year==1582 && month==10)
			{
				day_x=21;
				if(day>=15)
				{
			        k=year%100;j=year/100;l=day;m=month;
			        n=(l+(26*(m+1)/10)+k+(k/4)+(j/4)+5*j)%7;
			        switch(n)
			        {
				    case 0:
					    printf("星期六");
					    break;
				    case 1:
					    printf("星期日");
					    break;
				    case 2:
					    printf("星期一");
					    break;
				    case 3:
					    printf("星期二");
					    break;
				    case 4:
					    printf("星期三");
					    break;
				    case 5:
					    printf("星期四");
					    break;
				    case 6:
					    printf("星期五");
					    break;
			        }
			        break;
			    }
			    else
			    {
			    	l=day+10;
			    	k=year%100;j=year/100;m=month;
			        n=(l+(26*(m+1)/10)+k+(k/4)+(j/4)+5*j)%7;
			        switch(n)
			        {
				    case 0:
					    printf("星期六");
					    break;
				    case 1:
					    printf("星期日");
					    break;
				    case 2:
					    printf("星期一");
					    break;
				    case 3:
					    printf("星期二");
					    break;
				    case 4:
					    printf("星期三");
					    break;
				    case 5:
					    printf("星期四");
					    break;
				    case 6:
					    printf("星期五");
					    break;
			        }
				}
				break;
			}
			else
			{
				k=year%100;j=year/100;l=day;m=month;
			    n=(l+(26*(m+1)/10)+k+(k/4)+(j/4)+5*j)%7;
			    switch(n)
			    {
				case 0:
					printf("星期六");
					break;
				case 1:
					printf("星期日");
					break;
				case 2:
					printf("星期一");
					break;
				case 3:
					printf("星期二");
					break;
				case 4:
					printf("星期三");
					break;
				case 5:
					printf("星期四");
					break;
				case 6:
					printf("星期五");
					break;
			    }
			}
            break;
        case 3:
            printf("请输入年份：\n");
            scanf("%d",&year);
            if(year%4==0 && year%100!=0 || year%400==0)
            {
            	printf("%d是闰年\n",year);
			}
			else
			{
				printf("%d不是闰年\n",year);
			}
            break;
        case 4:
        	a=choice;
        	if(a==4)
        	{
        		return 0;
			}
            break;
        default:
            printf("无效的选择，请重新输入(1~4):\n");
            scanf("%d",&choice);
            do
            {
            	if(choice>4 ||  choice==0)
            	{
            		printf("无效选择，请重新输入:");
            		continue;
				}
				else
				{
					break;
				}
			}
			while(choice<=4 && choice!=0);
			goto start;
    }
    return 0;
}