Question

i am using C++ win32 API…

i have these values.

pwdlastset date(ex:25-9-2012), current date(ex:1-11-2012), maxpwdage
count(ex 54 days) pwdwarningdays(14 days)…

Now i want to calculate password expiry date…

i have try the below code…

if(lastpwdchmon==currentMonth)
                        {
                        lCount=currentDay-lastpwdchday;
                        }
                        else if(lastpwdchmon<currentMonth)
                        {
                            lCount=((currentDay+30)-lastpwdchday);
                        }

but,i have a problem…

i mean,just i need to calculate how many days between the currentdate & pwdlastset date?

How to achieve this?

Answer 1

DATE is COM approach to hold date/time. its integral part contain number of days from an epoch(doesn’t matter here) and fractional part indicate time of the day. So to compute number of days between 2 DATE you can do this:

DATE d1 = get_date1(), d2 = get_date2();
int number_of_days = static_cast<int>( d1 - d2 );

To get current date as DATE you can use:

DATE get_now( bool asUTC = false ) {
    SYSTEMTIME stm;
    (asUTC ? ::GetSystemTime : ::GetLocalTime)( &stm );
    DATE res;
    SystemTimeToVariantTime( &stm, &res );
    return res;
}

To convert fields of date/time into DATE you may use:

DATE to_date( int year, WORD month, WORD day,
    WORD h = 0, WORD m = 0, WORD s = 0, WORD ms = 0 )
{
    SYSTEMTIME stm = { year, month, 0, day, h, m, s, ms };
    DATE res;
    if( !SystemTimeToVariantTime(&stm, &res) ) {/* Handle error */}
    return res;
}