请问如何用两个时间相减获得相差的年数阿？

Question

当前时间减去生日得出的就是时间差。procedure TForm1.Button1Click(Sender: TObject);
var
  a: TDateTime;
begin
  a:=date-EncodeDate(1999,8,18);
  showmessage(datetostr(a));
end;

Answer 1

var
  a, b: TDateTime;
  Yeara, Yearb, temp: Word;DecodeDate(a, Yeara, temp, temp);
DecodeDate(b, Yearb, temp, temp);
ShowMessage(IntToStr(a - b));

Answer 2

var
   Iage:Integer;
   BirthdayDate,TodayDate:TDateTime;
begin
     ages:=StrToInt(copy(DateToStr(TodayDate),1,4))-
           StrToInt(copy(DateToStr(BirthdayDate),1,4));
end;

Answer 3

Age=StrToInt(FormatDateTime('yyyy', Now()))-StrToInt(copy(DateToStr(BirthdayDate),1,4));