How can i found the time(hh:mm:ss) between two tdatetime 1

[Szilveszter]

Hi,
I need a time between to date.
I want to count the time between log in and log out.
If I press a button "log in" then a date will be the begindate, and if I press the button "log out" then will be written out that how many hour, minute and second i have spend between log in and log out.
thanks for the answers, if it can be understand me

 

[DjangMan]

The time apart in seconds would be:

(LogOutTime - LogInTime) * 24 * 60 * 60

and from there you can figure out the number of hours, minutes and seconds.