Удалить все элементы стека, равные последнему

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
  stek=^pstek;
 pstek=record
 info:integer;
 next:stek;
 end;
var
  Form1: TForm1;
 p,q,bs1,bs2,bs:stek;
implementation
 
{$R *.dfm}
 procedure first_element(x:integer; var bs:stek);
begin
new(bs);
bs^.next:=q;
bs^.info:=x;
q:=bs;
end;
procedure vivod_steka(bs:stek; var label1:TLabel);
begin
q:=bs;
repeat
 label1.caption:=label1.caption+inttostr(q^.info)+#13;
 q:=q^.next;
until q=nil;
end;
 
procedure push(x:integer; var bs:stek);
begin
new(bs);
bs^.next:=q;
bs^.info:=x;
q:=bs;
end;
 
procedure pop(a3:stek; var c:integer; var a4:stek);
begin
c:=a3^.info;
a4:=a3^.next;
dispose(a3);
end;
procedure TForm1.Button1Click(Sender: TObject);
  var
a,i:integer;
b:stek;
n:stek;
begin
label1.Caption:='';
label2.Caption:='';
randomize;
a:=random(10);
first_element(a,bs1);
for i:=1 to 10 do
 begin
 a:=random(10);
 push(a,bs1);
 end;
repeat
 label1.caption:=label1.caption+inttostr(bs1^.info)+#13;
 b:=bs1;
 bs1:=bs1^.next;
until bs1=nil;
bs1:=q;
repeat
if bs1^.info<>b^.info then
 begin
 n:=bs1;
 label2.caption:=label2.caption+inttostr(n^.info)+#13;
 bs:=bs1;
 end;
bs1:=bs1^.next;
until bs1=nil;
end;
end.