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# Queue data structure

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queue in data structure

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### Queue data structure

1. 1. QUEUE Anoop joseph Free Powerpoint Templates Page 1
2. 2. Queue• Ordered collection of homogeneous elements• Non-primitive linear data structure.• A new element is added at one end called rear end and the existing elements are deleted from the other end called front end.• This mechanism is called First-In-First-Out (FIFO).• Total no of elements in queue= rear – front +1 Free Powerpoint Templates Page 2
3. 3. Fig: Models of a Queue Free Powerpoint Templates Page 3
4. 4. Operations On A Queue1.To insert an element in queue2.Delete an element from queue Free Powerpoint Templates Page 4
5. 5. The Queue OperationPlacing an item in a queue is called“insertion or enqueue”, which is doneat the end of the queue called “rear”. Front Rear Free Powerpoint Templates Page 5
6. 6. The Queue Operation Removing an item from a queue is called “deletion or dequeue”, which is done at the other end of thequeue called “front”. Front Rear Free Powerpoint Templates Page 6
7. 7. Algorithm QINSERT (ITEM)1.If (rear = maxsize-1 ) print (“queue overflow”) and return2.Else rear = rear + 1 Queue [rear] = item Free Powerpoint Templates Page 7
8. 8. Algorithm QDELETE ()1.If (front =rear) print “queue empty” and return2. Else Front = front + 1 item = queue [front]; Return item Free Powerpoint Templates Page 8
9. 9. Queue Applications Real life examples Waiting in line Waiting on hold for tech support Applications related to Computer Science Round robin scheduling Job scheduling (FIFO Scheduling) Key board buffer Free Powerpoint Templates Page 9
10. 10. 3 states of the queue1.Queue is empty FRONT=REAR2.Queue is full REAR=N3.Queue contains element >=1 FRONT<REAR NO. OF ELEMENT=REAR-FRONT+1 Free Powerpoint Templates Page 10
11. 11. Representation Of Queues1.Using an array2.Using linked list Free Powerpoint Templates Page 11
12. 12. Free Powerpoint Templates Page 12