with Text_IO; use Text_IO;

package Int_Set is
	type Integer_Set is private;

	function Empty_Integer_Set return Integer_Set;
	function Has_Integer(Set : Integer_Set; Value : Integer) return Boolean;
	procedure Add_Integer(Set : in out Integer_Set; Value : in Integer);
	procedure Remove_Integer(Set : in out Integer_Set; Value : in Integer);

private
	type List_Node;
	type List_Node_Access is access List_Node;
	type List_Node is record
		Value : Integer;
		Next : List_Node_Access;
	end record;

	type Integer_Set is record
		Head : List_Node_Access;
	end record;
end Int_Set;