calendar object
This method will add a number of days to the day property.
bool add_days(int days)
Parameters:
days
The number of days to add.
Return value:
true on success, false on failure.
Remarks:
A negative value in the days parameter will subtract days from the current day.
Any number of days can be added or subtracted. The month and year properties will adjust accordingly.
Example:

    // Create a calendar and set it to October 7, 1767 at 09:00 and add a week.

    void main()
    {
    calendar test;
    test.set(1767, 10, 7, 9, 0, 0);
    test.add_days(7);
    alert("Date", "The date is "+test.weekday_name+", "+test.month_name+" "+test.day+", "+test.year+", at "+test.hour+":"+test.minute+":"+test.second);
    }