/*This program counts the days between two dates input by the user*/
#include <stdio.h>
 
int yr1; /*global variables because all these need to be visible by multiple functions*/
int yr2; /*I don't know how to use pointers to return more than 1 variable from a function*/
int m1;
int m2;
int d1;
int d2;
int leap;
 
main()
{
      int numdays [13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; /*13 members*/
      int totaldays; /*so that 1 would match up with January, fixing notation problems*/
      int year;
      int month;
      int day; 
      inputdata();
      for (year = (yr1 + 1); year < yr2; year ++) /*processes complete years*/
      {
          leapyr(year);
          if (leap == 1)
             totaldays += 366;
             else totaldays += 365;
      }
      year = yr1;
      for(month = m1 + 1; month <= 12; month++) /*processes incomplete year 1*/
      {
          leapyr (year);
          if (leap == 1)
             numdays[2] = 29;
             else numdays[2] = 28;
          totaldays = totaldays + numdays[month];
      }
      month = m1;
      for(day = d1; day <= numdays [month]; day++) /*processes incomplete month 1*/
      {   
          leapyr (year);
          if (leap == 1)
          numdays[2] = 29;
          totaldays += 1;
      }
 
      year = yr2;
      for(month = m2 - 1; month >= 1; month--) /*processes incomplete year 2*/
      {
          leapyr (year);
          if (leap == 1)
          numdays[2] = 29;
          totaldays += numdays[month];
      }
      month = m2;
      for(day = d2; day > 1; --day) /*processes incomplete month 2*/
      {
          totaldays += 1; /*no need for leapyr function here- don't need to know month max*/
      }
      printf("Total number of days between two given dates is: %d days", totaldays);
      getch();
 
 
}
 
int inputdata() /*function works as planned- already tested*/
{
     printf("This program calculates the number of days between two given dates\n");
     printf("Enter beginning date in form month/day/year: ");
     scanf( "%d/%d/%d", &m1, &d1, &yr1);
     printf("Enter ending date in form month/day/year: ");
     scanf("%d/%d/%d", &m2, &d2, &yr2);
}
 
int leapyr (year)
{
    int leap = 0;
    if (year % 4 == 0)
       leap = 1;
       else
       if (year % 100 == 0)
          leap = 0;
          else
          if (year % 400 == 0)
             leap = 1;
    printf("leap is: %d\n", leap);
    return leap;
}

leapyr (year);
if (leap == 1)

leap = leapyr(year)

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
 
time_t tokenizedate(const char* datestr)
{
    struct tm tm;
    memset(&tm,0,sizeof(struct tm));
    tm.tm_mday = ((datestr[0] - '0') * 10) + (datestr[1] - '0');
    tm.tm_mon = ((datestr[2] - '0') * 10) + (datestr[3] - '0') - 1;
    tm.tm_year = atoi(&datestr[4]) - 1900;
    return mktime(&tm);
}
 
int main()
{
    time_t t1, t2;
    char date1[40], date2[40];
    time_t seconds = 0, minutes = 0, hours = 0, days = 0, months = 0;
    printf("Enter first date (DDMMYYYY format)\n");
    fgets(date1, sizeof(date1), stdin);
    printf("Enter second date (DDMMYYYY format)\n");
    fgets(date2, sizeof(date2), stdin);
    t1 = tokenizedate(date1);
    t2 = tokenizedate(date2);
    seconds = t2 - t1;
    minutes = seconds / 60;
    hours = seconds /(60 * 60);
    days = seconds / (60 * 60 * 24);
 
 
}

 returnValue = myFunction(argument);

int leapyr(void)
{
    int leap;   // locally defined, not the same variable in "main"
 
    // do your stuff
 
    return leap;
}

leap = leapyr();