So if I want add a year to a date and time I just have to add the number of seconds in a year which sounds ludicrously easy I agree. I want to know the exact d

So if I want add a year to a date and time I just have to add the number of seconds in a year which sounds ludicrously easy I agree. I want to know the exact date and time one year from February the 29th at 12:00 hours 2012. I want the answer to be consistent so what is the date and how many seconds do I add? I would also like to know the exact date and time one year from February the 28th at 12:00 hours 2011. I want the answer to be consistent so what is the date and how many seconds do I add?