C language Calculation This is the first day of the year __c language

int day (int-year, int month, int day)
{
   int i;int days = 0;
   int months[12] = {31,0,31,30,31,30,31,31,30,31,30,31};
   Determine whether a year is a leap years to see if it satisfies one of the 2 conditions (which cannot be met at the same time) 
   if ((year% 400 = 0) | | (Year% 4 = 0) && (year% 100!= 0)) A multiple of 400 or divisible by 4 and not divisible by 
      months[1] =;
   else
      months[1] =;
   for (i = 1; i < month i++) days
      + + months[i];
   Days = day;
   return days;
}