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

# YearSpan

Calculate the approximate number of years between two DateTime values.

## Declaration

Source position: dateutil.inc line 271

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

## Arguments

 ANow First moment in time AThen Second moment in time

## Function result

Number (fractions included) of years between ANow and AThen

## Description

YearSpan returns the number of years between ANow and AThen, including any fractional parts of a year. This number is an approximation, based on an average number of days of 365.25 per year (average over 4 years).

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

## Example

Program Example63;

{ This program demonstrates the YearSpan function }

Uses SysUtils,DateUtils;

Procedure Test(ANow,AThen : TDateTime);

begin
Write('Number of years between ');
Write(DateToStr(AThen),' and ',DateToStr(ANow));
Writeln(' : ',YearSpan(ANow,AThen));
end;

Var
D1,D2 : TDateTime;

Begin
D1:=Today;
D2:=Today-364;
Test(D1,D2);
D2:=Today-365;
Test(D1,D2);
D2:=Today-366;
Test(D1,D2);
D2:=Today-390;
Test(D1,D2);
D2:=Today-368;
Test(D1,D2);
D2:=Today-1000;
Test(D1,D2);
End.