SmartPascal
DaySpan
Function		 Gives the fractional number of days between 2 dates DateUtils unit
 function DaySpan ( const ToDate, FromDate : TDateTime ) : Double;
Description
The DaySpan function subtracts the FromDate from the ToDate, returning the fractional days difference.
 
The Double return value contains the number of days as the integral part, and the part-day remainder as the fractional part.
 
For example, a difference of 2 days and 6 hours would give a value of 2.25
Related commands
DaysBetween Gives the whole number of days between 2 dates
DaysInAMonth Gives the number of days in a month
DaysInAYear Gives the number of days in a year
 
Example code : Find the days difference between two date+time values.
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
 
unit Unit1;
 
interface
 
uses
  DateUtils,   // Unit containing the DaySpan command
  SysUtils,
  Forms, Dialogs;
 
type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  end;
 
var
  Form1: TForm1;
 
implementation
{$R *.dfm} // Include form definitions
 
procedure TForm1.FormCreate(Sender: TObject);
var
  fromdate, toDate : TDateTime;

begin
  // Set up our date variables
  fromDate := EncodeDateTime(2000, 01, 01, 0, 0, 0, 0);
  toDate   := EncodeDateTime(2000, 01, 02, 12, 0, 0, 0);

  // Display these dates and the days between them
  ShowMessage('From date = '+DateTimeToStr(fromDate));
  ShowMessage('To   date = '+DateTimeToStr(toDate));
  ShowMessage('Fractional days difference = '+
              FloatToStr(DaySpan(toDate, fromDate))+' days');
end;
 
end.
Hide full unit code
   From date = 01/01/2000
   To   date = 02/01/2000 12:00:00
   Fractional days difference = 1.5 days