I am new in Delphi
programming.
While going through the Data Types
in Delphi
I found TDateTime
.
While using it in my test application I come to know that the TDateTime
Object provide me a Float\Double
value.
I am little curious about TDateTime
How it calculate the Date Time
to Double
value.
Below is the example code which I had used:
var
LDateTime: TDateTime;
LFloat: Double;
begin
LDateTime := now;// current DateTime
LFloat:= LDateTime; // provide me a float value
end;
Is it using any formula to calculate Date and Time Value
from Windows?
Can anyone suggest/provide me for some more information about working of TDateTime
?
Thanks in advance.
The float represents the number of days since 30.12.1899. So float value = 1 would be 31.12.1899, 2 = 01.01.1900 and so on. The time is saved as a fraction of the day. 0.25 = 06:00, 0.5 = 12:00, 0.75 = 18.00 ...
So the 31.12.1899 12:00 would be equal to 1.5.
This makes TDateTime really easy to work with. To get the difference in days just substract two DateTimes.
02.01.2015 - 01.01.2015 = 1
Simple as it can be. To get the difference in hours just multiply by 24.
Also have a look at the functions in Unit DateUtils. They come in handy at times.