输入两个日期， 求之间的天数？

不知哪里有问题， 指教。。。
#include<stdio.h>
struct date{
    int days;
    int monthes;
    int year;
};

int main(void)
{
    
long int N(struct date day);
long double N1,N2,result;
        
struct date thisday, nextday;
printf("Enter the date of start:");
scanf("%d%d%d", &thisday.monthes, &thisday.days, &thisday.year);
printf("Enter the date of end:");
scanf("%d%d%d", &nextday.monthes, &nextday.days, &nextday.year);
  N1=N(nextday);
  N2=N(thisday);
   result=N1-N2;
  printf("the days is: %ld\n", result);
return 0;
}
long int N(struct date day)
{
   int f(struct date a), g(struct date b);
   long int Days;
Days=1461*f(day)/4+153*g(day)/5+day.days;
      return Days;
}
int f(struct date a)
{
long int p;
if(a.monthes<=2)
p=a.year-1;
else p=a.year;
return p;
}

int g(struct date b)
{
long int q;
if(b.monthes<=2)
q=b.monthes+13;
else q=b.monthes+1;
return q;
}
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你找一下07年上半年的程序员考试的下午题目上面有类似的题目
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