unit ulist;
interface

type
	Plist=^Tlist;
	Tlist=record
		key:integer;
		pnext:plist;
	end;

function createElement(key:integer):plist;
procedure addfirstelement(var PH:plist; p:plist);
procedure addlastelement(var PH:plist; p:plist);
procedure InsertElement(prevEl:plist; p:plist);
function deleteElement(prevEl:plist):plist;
function deletefirstElement(var pH:plist):plist;
procedure disposeList(var pH:plist);
function countElements(pH:plist):integer;

type
 TlistAction=procedure(key:integer);
procedure listAction(ph:plist; proc:TListAction); 
  
implementation

function createElement(key:integer):plist;
begin
end;

procedure addfirstelement(var PH:plist; p:plist);
begin
end;

procedure addlastelement(var PH:plist; p:plist);
begin
end;

procedure InsertElement(prevEl:plist; p:plist);
begin
end;

function deleteElement(prevEl:plist):plist;
begin
end;

function deletefirstElement(var pH:plist):plist;
begin
end;

procedure disposeList(var pH:plist);
begin
end;

function countElements(pH:plist):integer;
begin
end;

procedure listAction(ph:plist; proc:TListAction); 
begin
end;

end.