type
   TMyMass = class
   private
     { Private declarations }
   public
     MyMass : Array of Integer;
     Procedure MyMassInit(i:integer; x:integer);
   end;

var
   Form3: TForm3;
   Mass: TMyMass;
   i: integer;

Procedure TMyMass.MyMassInit(i:integer; x:integer);
begin
Setlength(MyMass,i+1);
MyMass[i]:=x;
end;

procedure TForm3.FormCreate(Sender: TObject);
begin
Mass := TMyMass.Create;

randomize();

for i := 0 to 10 do
begin
Mass.MyMassInit(i,random(100));
memo1.Lines.Add(inttostr(Mass.MyMass[i]))
end;

Mass.Free;
end;