Нужно рассчитать день, который будет "послезавтра", по заданной дате

#include <iostream>

#include <iostream>
 
struct Date{
    unsigned day;
    unsigned month;
    unsigned year;
};
 
bool isLeapYear(int year)
{
 
    return ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0));
}
 
Date next_day(Date now, unsigned days){
 
    unsigned leap = isLeapYear(now.year);
    unsigned last_days[] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 
    last_days[2] += leap;
 
 
    if ( (now.day + days) < last_days[now.month])
    {
        now.day += days;
        return now;
    }
 
    now.day = days - leap;
 
    if (now.month < 12){
        now.month++;
        return now;
    }
 
    now.month = 1;
    now.year++;
    return now;
}
 
 
int  main()
{
    Date d = { 28, 2, 2008 };
    Date r = next_day(d, 2);
 
    std::cout << r.day << " " << r.month << " " << r.year << std::endl;
 
    d.year = 2009;
    r = next_day(d, 2);
 
    std::cout << r.day << " " << r.month << " " << r.year << std::endl;
    return 0;
}