保留小数问题。

procedure TForm1.edt15Exit(Sender: TObject);
var
  a,b,c:Double;
  begin

   if not TryStrToFloat(Trim(edt14.Text),a) then
begin
   ShowMessage('请输入数字');
   edt14.SetFocus;
   exit;
end;
if not TryStrToFloat(Trim(edt15.Text),b) then
begin
   ShowMessage('请输入数字');
   edt15.SetFocus;
   exit;
end;

  c:=b/(a+b)*100;
  edt22.Text:=FloatToStr(round(c))+'%' ;