Revision as of 13:28, 20 November 2008 view source rosettacode>Mwn3d m →‎{{header\|Java}}: Changed the name of the interface class ← Older edit		Revision as of 13:30, 20 November 2008 view source rosettacode>Dmitry-kazakov m Typos Newer edit →
Line 2: [[Category:Encyclopedia]] [[Category:Object oriented]] '''Abstract type''' is a type without instances. In [[object-oriented programming]] abstract types are used for partial implementation of other types, which are later derived from it. Abstract type may provide implementation of some operations and/or components. Abstract types without any implementation are called '''interfaces'''. In the languages that do not support multiple [[inheritance]] ([[Ada]], [[Java]]), interfaces are usually allowed to be multiply inherited from. The languages with multiple inheritance (like [[C++]]), usually make no distinction between partially implementable abstract types and interfaces. Because the abstract type's implementation is incomplete, if any, it makes no sense to have any instances (objects) of it. Therefore an [[object-oriented programming \| OO]] language would prevent creation of such objects. Line 31: end record; overriding procedure Finalize (X : in out Node); -- Removes the node from its list if any overriding procedure Dequeue (Lounge : in out ~~Queue~~Node; Item : in out Element); overriding procedure Enqueue (Lounge : in out ~~Queue~~Node; Item : in out Element); procedure Process (X : in out Node) is abstract; -- To be implemented </ada>

Abstract type: Difference between revisions