procedure TForm1.Button1Click(Sender: TObject);
vari: Real;
begini := 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;