[Overview][Constants][Procedures and functions][Index] Reference for unit 'DateUtils' (#rtl)

# HourSpan

Calculate the approximate number of hours between two TDateTime values.

## Declaration

Source position: dateutil.inc line 288

 function HourSpan( const ANow: TDateTime; const AThen: TDateTime ):Double;

## Arguments

 ANow First moment in time AThen Second moment in time

## Function result

Number (fractions included) of hours between ANow and AThen

## Description

HourSpan returns the number of Hours between ANow and AThen, including any fractional parts of a Hour.

## See also

 YearSpan Calculate the approximate number of years between two TDateTime values. MonthSpan Calculate the approximate number of months between two TDateTime values. WeekSpan Calculate the approximate number of weeks between two TDateTime values. DaySpan Calculate the approximate number of days between two TDateTime values. MinuteSpan Calculate the approximate number of minutes between two TDateTime values. SecondSpan Calculate the approximate number of seconds between two TDateTime values. MilliSecondSpan Calculate the approximate number of milliseconds between two TDateTime values. HoursBetween Calculate the number of whole hours between two TDateTime values.

## Example

```Program Example67;

{ This program demonstrates the HourSpan function }

Uses SysUtils,DateUtils;

Procedure Test(ANow,AThen : TDateTime);

begin
Write('Number of hours between ');
Write(DateTimeToStr(AThen),' and ',DateTimeToStr(ANow));
Writeln(' : ',HourSpan(ANow,AThen));
end;

Var
D1,D2 : TDateTime;

Begin
D1:=Now;
D2:=D1-(59*OneMinute);
Test(D1,D2);
D2:=D1-(61*OneMinute);
Test(D1,D2);
D2:=D1-(122*OneMinute);
Test(D1,D2);
D2:=D1-(306*OneMinute);
Test(D1,D2);
D2:=D1-(5.4*OneHour);
Test(D1,D2);
D2:=D1-(2.5*OneHour);
Test(D1,D2);
End.
```