缘由根据当天日期输出明天的日期(需对闰年做判定)。日期类型结构体如下： struct data{ int year; int month; int day;};-编程语言-CSDN问答

struct mdata{ int year; int month; int day; }mdata;
int 天数(int year, int month)
{
	switch (month)
	{
	case 1: case 3: case 5: case 7: case 8:case 10:case 12:
		return 31; break;
	case 4:case 6:case 9:case 11:
		return 30; break;
	case 2: return 28 + ((year % 4 == 0 && year % 100 != 0 || year % 400 == 0) ? 1 : 0);  break;
	}
}
void 明天()
{//缘由https://ask.csdn.net/questions/7718476
	scanf_s("%d %d %d", &mdata.year, &mdata.month, &mdata.day);
	if (mdata.day == 0 || mdata.day > 天数(mdata.year, mdata.month)) printf_s("非法日期：%d %d %d", mdata.year, mdata.month, mdata.day);
	else
	{
		if (mdata.month < 12)if (mdata.day == 天数(mdata.year, mdata.month))++mdata.month, mdata.day = 1; else ++mdata.day;
		else if (mdata.day == 天数(mdata.year, mdata.month))++mdata.year, mdata.month = mdata.day = 1; else ++mdata.day;
		printf_s("%d %d %d", mdata.year, mdata.month, mdata.day);
	}
}



	明天();