通过具体日期来求出总天数，代码运行没有错误，但运行显示结果有错误。

#include <stdio.h>
int main()
{
    int year,month,day,sum=0;
    printf("请输入你的年 月 日：\n");
    scanf("%d%d%d",&year,&month,&day); 
    switch(month)
    {
        case2:sum=31;break;
        case3:sum=28+31;break;
        case4:sum=28+31+30;break;
        case5:sum=28+31+30+30;break;
        case6:sum=28+31+30+30+31;break;
        case7:sum=28+31+30+30+31+30;break;
        case8:sum=28+31+30+30+31+30+31;break;
        case9:sum=28+31+30+30+31+30+31+31;break;
        case10:sum=28+31+30+30+31+30+31+31+30;break;
        case11:sum=28+31+30+30+31+30+31+31+30+31;break;
        case12:sum=28+31+30+30+31+30+31+31+30+31+31;break;
    }
        sum=sum+day;
        if(year%400==0||(year%4==0&&year%100!=0))
        {
            if(month>2){
            sum++;
            }
        }
        printf("%d\n",sum);
    return 0;
    
}

代码运行没有错误，但运行出来结果有错。

case2 case中间是不是少了一个空格？

#include <stdio.h>
int main()
{
    int year, month, day, sum = 0;
    printf("请输入你的年 月 日：\n");
    scanf("%d%d%d", &year, &month, &day);
    switch (month)
    {
    case 2:sum = 31; break;
    case 3:sum = 28 + 31; break;
    case 4:sum = 28 + 31 + 30; break;
    case 5:sum = 28 + 31 + 30 + 30; break;
    case 6:sum = 28 + 31 + 30 + 30 + 31; break;
    case 7:sum = 28 + 31 + 30 + 30 + 31 + 30; break;
    case 8:sum = 28 + 31 + 30 + 30 + 31 + 30 + 31; break;
    case 9:sum = 28 + 31 + 30 + 30 + 31 + 30 + 31 + 31; break;
    case 10:sum = 28 + 31 + 30 + 30 + 31 + 30 + 31 + 31 + 30; break;
    case 11:sum = 28 + 31 + 30 + 30 + 31 + 30 + 31 + 31 + 30 + 31; break;
    case 12:sum = 28 + 31 + 30 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 31; break;
    }
    sum = sum + day;
    if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
    {
        if (month > 2) {
            sum++;
        }
    }
    printf("%d\n", sum);
    return 0;
}