package body pila is

   top : Integer := 0;
   stack: array (1..100) of Integer;

   function Empty return Boolean is
   begin
      return top = 0;
   end Empty;

   procedure Push(E:Elemento) is
   begin
      if (top /= 100) then
         top := top + 1;
         stack(top) := Integer(E);
      end if;
   end Push;

   procedure Pop(E: out Elemento) is
   begin
      E := Elemento(stack(top));
      top := top - 1;
   end Pop;


end pila;