这几天学到了结构体，写了代码，但是出错，请各位给我看看：

#include <stdio.h>
#include <string.h>
struct data
{
    int year,day;
    int month[12]={31,28,31,30,31,30,31,31,30,31,30,31};
}find;
void yearmonthday()
{
    int sum,i,j;
    printf("please input the year month and day:\n");
    scanf("%d %d %d",&find.year,&i,&find.day);
    if(find.year%4==0&&find.year%100==0||find.year%400==0)
    {find.month[1]=29;}
    for(j=0;j<i;j++)
    {
        sum=sum+find.month[j];
    }
    sum=sum+find.day;
    printf("the day is %d",sum);
}
void yearday()
{  
    int i,sum=0;int month1,day1;
    printf("please input the year and day:\n");
    scanf("%d %d",&find.year,&find.day);
    if(find.year%4==0&&find.year%100==0||find.year%400==0)
    {find.month[1]=29;}
    month1=find.day/30;
    day1=find.day%30;
    printf("month=%d,day=%d",month1,day1);
   
}
void main()
{  
    int switches;
    printf("please input the case:\n");
    printf("1.please input the year,day,give your month day.\n");
    printf("2.please input the year month day give your data.\n");
    printf("plase chose (1\2):\n");
    scanf("%d",&switches);
    switch(swithes)
    {
    case 1:yearday();break;
    case 2:yearmonthday();break;
    default:printf("error!\n");break;break;
    }
   
}

第一个函数是：给定年、月、日，求天数。
第二个函数是：给定年和天数求日月，第二个函数也不会写。
各位高手帮帮忙啊！