indexing
description: "Structures that can hold zero or more items"
library: "Gobo Eiffel Structure Library"
author: "Eric Bezault <ericb@gobo.demon.co.uk>"
copyright: "Copyright (c) 1997, Eric Bezault"
deferred class interface
DS_CONTAINER [G]
feature -- Measurement
count: INTEGER
-- Number of items in structure
feature -- Comparison
is_equal (other: like Current): BOOLEAN
-- Is current structure equal to other?
require -- from GENERAL
other_not_void: other /= void
ensure -- from GENERAL
symmetric: Result implies other.is_equal (Current);
consistent: standard_is_equal (other) implies Result
ensure then
same_count: Result implies count = other.count
feature -- Status report
is_empty: BOOLEAN
-- Is structure empty?
feature -- Removal
wipe_out
-- Remove all items from structure.
ensure
wipe_out: is_empty
invariant
-- from GENERAL
reflexive_equality: standard_is_equal (Current);
reflexive_conformance: conforms_to (Current);
positive_count: count >= 0;
empty_definition: is_empty = (count = 0);
end -- class DS_CONTAINER