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

# YearSpan

Calculate the approximate number of years between two TDateTime values.

## Declaration

Source position: dateutil.inc line 284

`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

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.
HourSpan |  | Calculate the approximate number of hours 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.
YearsBetween |  | Calculate the number of whole years between two TDateTime 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.