TCustomUser = class
  protected
    fRealName: string;
  public
    MegaInfo: TMegaUserInfo;
    function GetRealName: string;
    constructor Create(username: string);
    destructor Destroy; override;
    (* метод Destroy здесь перекрывает одноименный метод родительского
    класса, поэтому использована инструкция override *)
 end;

 TUser = class (TCustomUser) // наследование (Объявление Tuser как предок TCustomUser)
  private
    fLogin: string;
    fPassword: string;
    procedure setPassword(newpass: string);
  published
    property Login: string read fLogin write fLogin;
    property Password: string read fPassword write setPassword;
    constructor Create(username, userlogin: string);
 end;

function TCustomUser.GetRealName: string;
begin
 result:=fRealName;
 writeln(' >> Calls TCustomUser.GetRealName');
end;

constructor TCustomUser.Create(username: string);
begin
 inherited Create;
 MegaInfo:=TMegaUserInfo.Create;
 fRealName:=username;
 writeln(' >> Calls TCustomUser.Create with '+username);
end;

destructor TCustomUser.Destroy;
begin
 MegaInfo.Free;
 inherited Destroy;
 writeln(' >> Calls TCustomUser.Destroy');
end;

constructor TUser.Create(username, userlogin: string);
begin
 inherited Create(username);     // Полиморфизм (ключевое слово inherited отсылает нас к
 fLogin:=userlogin;              // предку (для Tuser это TCustomUser)
 fPassword:='password';
 writeln(' >> Calls TUser.Create with '+username+' and '+userlogin);
end;

procedure TUser.setPassword(newpass: string);
begin
 if Length(newpass)>3 then fPassword:=newpass
   else writeln('Error! Password is too short!');
 writeln(' >> Calls TUser.setPassword with '+newpass);
end;

var
 User: TUser;

begin
 writeln('Press ENTER to create a new TUser insance');
 readln;
 User:=TUser.Create('Ivan Ivanovich','Vano');
 writeln(#10+'Press ENTER to access to parent class method');
 readln;
 writeln(User.GetRealName);
 writeln(#10+'Press ENTER to access to TAddress record');
 readln;
 with User.MegaInfo.Address do begin
   PostIndex:=119071;
   City:='Moscow';
   writeln(PostIndex);
   writeln(User.MegaInfo.Address.City);
 end;
 writeln(#10+'Press ENTER to destroy TUser instance');
 readln;
 User.Destroy;
 writeln(#10+'Press ENTER to exit');
 readln;
end.