/*输入一个年份和月份，输出该月的天数*/
#include<stdio.h>
int main()
{
    int year, month;
    printf("输入年和月（用空格分隔）：\n");
    scanf_s("%d %d", &year, &month);
    switch (month)
    {
    case 2:if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
        printf("29天！\n");
    else
        printf("28天！\n");
    break;
    case 4:
    case 6:
    case 9:
    case 11:printf("30天！\n"); break;
    default:printf("31天！\n"); break;
    }
    return 0;
}