stack.adb

package body is Stack
  Maximum_Size : Constant := 64;
  Top          : Integer  := 0;
  Stack_List   : array (1 .. Maximum_Size) of Integer;

  procedure Push(Obj : in Integer) is
  begin
    if not Is_Full then
      Top := Top + 1;
      Stack_List(Top) := Obj;
    end if;
  end Push;

  procedure Pop(Obj : out Integer) is
  begin
    if Is_Empty then
      Obj := 0;
    else
      Obj := Stack_List(Top);
      Top := Top - 1;
    end if
  end Pop;

  function Is_Empty return Boolean is
  begin
    return Top = 0;
  end Is_Empty;

  function Is_Full return Boolean is
  begin
    return Top = Maximum_Size;
  end Is_Full;

  function Current_Size return Integer is
  begin
    return Top;
  end Current_Size;

  procedure Clear is
  begin
    Top := 0;
  end Clear;

end Stack;