// 处理每个月的天数 int days_in_month;

switch (month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: days_in_month = 31; break; case 4: case 6: case 9: case 11: days_in_month = 30; break; case 2: // 判断是否是闰年 if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) { days_in_month = 29; } else { days_in_month = 28; } break; default: days_in_month = 0; // 无效的月份 break; }

printf("%d\n", days_in_month); return 0;