******** fig3.43 **********

	STACK
	create_stack( void )
	{
		STACK S;

		S = (STACK) malloc( sizeof( struct node ) );
		if( S == NULL )
			fatal_error("Out of space!!!");
		return S;
	}

	void
	make_null( STACK S )
	{
		if( S != NULL )
			S->next = NULL;
		else
			error("Must use create_stack first");
	}