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YearSpan function

In unit DateUtils

Calculate the approximate number of years between two TDateTime values.

Declaration

pascal
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).

See also

Example: ex63

pascal
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.

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.