Abstract type: Difference between revisions

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procedure Process (X : in out Node) is abstract; -- To be implemented</lang>

Here Node is an abstract type that is inherited from Limited_Controlled and implements a node of a [[Doubly-Linked List (element) | doubly linked list]]. It also implements the interface of a queue described above, because any node can be considered a head of the queue of linked elements. For the operation Finalize an implementation is provided to ensure that the element of a list is removed from there upon its finalization. The operation itself is inherited from the parent type Limited_Controlled and then overridden. The operations Dequeue and Enqueue of the Queue interface are also implemented.

=={{header|Aikido}}==

An abstract class contains functions that have no body defined. You cannot instantiate a class that contains abstract functions.

<lang aikido>class Abs {

public function method1...

public function method2...

}</lang>

Interfaces in Aikido define a set of functions, operators, classes, interfaces, monitors or threads (but no variables) that must be implemented by a class implementing the interface.

<lang aikido>interface Inter {

function isFatal : integer

function operate (para : integer = 0)

operator -> (stream, isout)

}</lang>

=={{header|C}}==