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Engineering LibreTexts

10.6: Circular queue

  • Page ID
    34692
  • Operations on Circular Queue:

    • qInsert(value) This function is used to insert an element into the circular queue. In a circular queue, the new element is always inserted at Rear position.Steps:
      1. Create a new node dynamically and insert value into it.
      2. Check if front==NULL, if it is true then front = rear = (newly created node)
      3. If it is false then rear=(newly created node) and rear node always contains the address of the front node.
    • qRemove() This function is used to delete an element from the circular queue. In a queue, the element is always deleted from front position.Steps:
      1. Check whether queue is empty or not means front == NULL.
      2. If it is empty then display Queue is empty. If queue is not empty then step 3
      3. Check if (front==rear) if it is true then set front = rear = NULL else move the front forward in queue, update address of front in rear node and return the element.

    Here is an example of inserting and removing a few values with a circular queue

    Examples of operations on a circular Queue - "Circular Queue | Set 2 (Circular Linked List Implementation)" by andrew1234, Geeks for Geeks is licensed under CC BY-SA 4.0

    This is the same as the non-circular EXCEPT that you must update the rear->next value to point to the head when you qRemove(), and set the new rear->next when you qInsert().

    "Circular Queue | Set 2 (Circular Linked List Implementation)" by Arnab Kundu is licensed under CC BY-SA 4.0

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