判断这一天是这一年的第几天！

 //方法1
 1 #include "stdio.h"
 2 
 3 int main()
 4 {
 5     int year, month, day,sum=0;
 6     int days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; //初始化一年的十二个月，二月默认为28天 如果闰年修改days[1]
 7     printf("请输入年-月-日：");
 8     scanf_s("%d-%d-%d", &year, &month, &day);
 9     if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0)//判断是否是闰年 是闰年把days[1] = 29
10     {
11         days[1] = 29;
12     }
13     for (int i = 0; i < month-1; i++)
14     {
15         sum += days[i];      //累加求和
16     }
17     printf("这是这一年的%d天！",sum+day);
18 }

//方法二
#include "stdio.h"

int main()
{
	int year, month, day,days=0,d;
	printf("请输入年-月-日：");
	scanf_s("%d-%d-%d",&year,&month,&day);
	for (int i = 1; i < month; i++)
	{
		switch (i)
		{
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12:d = 31; break;
		
		
		case 4:
		case 6:
		case 9:
		case 11:d = 30; break;

		case 2: 
		if (year % 4 == 0 && year % 100 != 0 || year % 400 ==0 )
		{
			d = 29;
		}
		else
		{
			d = 28;
		}
		break;
		}
		days += d;
	}
	printf("这是这一年的%d天！",days+day);
}