difftime issues

Code:

#include<iostream.h>
#include<time.h>

int main()
{
    // Set first date (22/2/1998):
    struct tm date1_struct={0};
    time_t    date1_t;
    date1_struct.tm_year = (1998 - 1900);
    date1_struct.tm_mon  = 2;
    date1_struct.tm_mday  = 22;
    date1_t = mktime(&date1_struct);

    // Set second date (1/3/1998):
    struct tm date2_struct={0};
    time_t    date2_t;
    date2_struct.tm_year = (1998 - 1900);
    date2_struct.tm_mon  = 3;
    date2_struct.tm_mday  = 1;
    date2_t = mktime(&date2_struct);

    // Display difference:
    cout << "Difference in days: " 
         << (((difftime(date2_t, date1_t)/60)/60)/24) << endl;

    return 0;
}

returns a value of 10 instead of 7.... I have a funny feeling I am missing something very small here.....

Thanks for the help!!

Yes, this is homework!!

That months count from 0 (not 1 as you expect), so you're really looking at march to april, not february to march