![9
Enqueue Algorithm
begin procedure enqueue(data)
if queue is full
return overflow
endif
rear ← rear + 1
queue[rear] ← data
return true
end procedure](https://image.slidesharecdn.com/5queue-210409103157/85/Algorithm-and-Data-Structure-Queue-9-320.jpg)
![Dequeue Algorithm
begin procedure dequeue
if queue is empty
return underflow
end if
data = queue[front]
front ← front + 1
return true
end procedure
12](https://image.slidesharecdn.com/5queue-210409103157/85/Algorithm-and-Data-Structure-Queue-12-320.jpg)
![Front
Front: Get the front item from queue.
13
Front Algorithm:
begin procedure front
return queue[top]
end procedure](https://image.slidesharecdn.com/5queue-210409103157/85/Algorithm-and-Data-Structure-Queue-13-320.jpg)
![Rear
Rear: Get the last item from
queue.
Rear Algorithm:
begin procedure rear
return queue[last]
end procedure
14](https://image.slidesharecdn.com/5queue-210409103157/85/Algorithm-and-Data-Structure-Queue-14-320.jpg)
Algorithm and Data Structure - Queue
- 1. Algorithm and Data Structure Andi Nurkholis, S.Kom, M.Kom Study Program of Informatics Faculty of Engineering and Computer Science SY. 2020-2021 April 19, 2021
- 2. 2 5 Queue
- 3. 3 What is Queue? Like Stack, Queue is a linear structure which follows a particular order in which the operations are performed. The order is First In First Out (FIFO). A good example of queue is any queue of consumers for a resource where the consumer that came first is served first.
- 5. 5 Queue VS Stack The difference between stacks and queues is in removing. In a stack we remove the item the most recently added; in a queue, we remove the item the least recently added
- 6. 6 Queue Operations 1) Enqueue 2) Dequeue 3) Front 4) Rear
- 7. 7 Enqueue Enqueue: Adds an item in the stack. If the stack is full, then it is said to be an Overflow condition.
- 8. Steps of Enqueue Step 1 − Check if the queue is full. Step 2 − If the queue is full, produce overflow error and exit. Step 3 − If the queue is not full, increment rear pointer to point the next empty space. Step 4 − Add data element to the queue location, where the rear is pointing. Step 5 − return success. 8
- 9. 9 Enqueue Algorithm begin procedure enqueue(data) if queue is full return overflow endif rear ← rear + 1 queue[rear] ← data return true end procedure
- 10. Dequeue Dequeue: Removes an item from the queue. The items are popped in the same order in which they are pushed. If the queue is empty, then it is said to be an Underflow condition. 10
- 11. Steps of Dequeue Step 1 − Check if the queue is empty. Step 2 − If the queue is empty, produce underflow error and exit. Step 3 − If the queue is not empty, access the data where front is pointing. Step 4 − Increment front pointer to point to the next available data element. Step 5 − Return success. 11
- 12. Dequeue Algorithm begin procedure dequeue if queue is empty return underflow end if data = queue[front] front ← front + 1 return true end procedure 12
- 13. Front Front: Get the front item from queue. 13 Front Algorithm: begin procedure front return queue[top] end procedure
- 14. Rear Rear: Get the last item from queue. Rear Algorithm: begin procedure rear return queue[last] end procedure 14
- 15. Working of Queue This abstract data type can be implemented in C in multiple ways. One such way is by using an array. Pro of using an array: Easy to implement. Con of using an array: Static Data Structure, fixed size. 15
- 16. Queue Application 1. CPU scheduling, Disk Scheduling 2. When data is transferred asynchronously between two processes.The queue is used for synchronization. For example: IO Buffers, pipes, file IO, etc 3. Handling of interrupts in real-time systems. 4. Call Center phone systems use Queues to hold people calling them in order. 16
- 17. Thank You, Next … Searching April 19, 2021 Andi Nurkholis, S.Kom, M.Kom Study Program of Informatics Faculty of Engineering and Computer Science SY. 2020-2021