Queues

1
Queues

• A first-in, first-out or FIFO data structure.
• Basic operations enqueue, Dequeue and Head.

2
Implementation

• Array based
• Pointer based (using linked list)

3
Basic Queue Operations
4
Queue Class Definition
5
Array Implementation
6
Array Implementation of a queue
7
Constructor, Destructor and Purge()
8
Head, Enqueue, and Dequeue
9
Linked-List Implementation
10
Constructor, Destructor and Purge()
11
Head, Enqueue and Dequeue
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Deques

• Double-ended queue.
• Insert and remove items at both ends of the pile.

13
Basic Operations
14
Deque Class Definition
15
Enqueue and Dequeue
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Specialization and Generalization

• Specialization
• Base class is general, derived class is
  restricted.
• class Queue public Deque
• Generalization
• Base class is restricted, derived class is
  general.
• class Deque public Queue

17
Array Implementation
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Head(), EnqueueHead(), DequeueHead()
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Tail(), EnqueueTail() DequeueTail()
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Linked-List Implementation
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Head(), EnqueueHead() and DequeueHead()
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Tail() EnqueueTail() and DequeueTail()
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Doubly-Linked and Circular Lists