时间的运算

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Real;
begin
  i := StrToDate('2008-1-1') - StrToDate('2007-1-1');
  ShowMessage(FloatToStr(i));  //返回的结果是365天

  i := StrToDate('2009-1-1') - StrToDate('2008-1-1');
  ShowMessage(FloatToStr(i));  //返回的结果是366天
end;