#include<stdio.h>
struct
{
    int year;
    int month[12];
    int day;
}days[2];
days[0].month[12]={31,28,31,30,31,30,31,31,30,31,30,31};
days[1].month[12]={31,29,31,30,31,30,31,31,30,31,30,31};
void sxrn();
void dit();
void sxrn(int year)
{
    if(year%4!=0)
        printf("该年不是闰年");
    else if(year%400==0 || year%4==0 && year%100!=0)
        printf("该年为闰年");
}
void dit(int year,int month,int day)
{
    int m,i,day_s=0;
    if(year%400==0 || year%4==0 && year%100!=0)
        m=1;
    else if(year%4!=0)
        m=0;
    for(i=0;i<month-1;i++)
        day_s+=days[m].month[i];
        day_s=day_s+day;
        printf("您输入的日期为该年的第%d天",day_s);
}
void main()
{
    int year,month,day;
    printf("请输入您要输入的日期");
    while(1)
    {
        scanf("%d %d %d",&year,&month,&day);
        if(month>=1 && month<=12)
            break;
    }
    sxrn(year);
    dit(year,month,day);
}
谢谢了

struct data
{
    int year;
    int month[12];
    int day;
}days[2] =  {0,31,28,31,30,31,30,31,31,30,31,30,31,0,0,31,29,31,30,31,30,31,31,30,31,30,31,0};        //在这里初始化

//days[0].month[12]={31,28,31,30,31,30,31,31,30,31,30,31};
//days[1].month[12]={31,29,31,30,31,30,31,31,30,31,30,31};

不会吧 和我想的一样的 我就是这样改的
哈哈