Data Structures and Algorithms - Old Questions

7. Describe circular Queue operations in array implementation.

Circular Queue is a linear data structure in which the operations are performed based on FIFO (First In First Out) principle and the last position is connected back to the first position to make a circle.

Graphical representation of a circular queue is as follows.

Initialization of Circular queue:

rear=front=MAXSIZE-1

Operations of Circular Queue

1. enQueue(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.

Algorithms for inserting an element in a circular queue:

This algorithm is assume that rear and front are initially set to MAZSIZE-1.

1. if (front==(rear+1)%MAXSIZE)

print Queue is full and exit

    else

rear=(rear+1)%MAXSIZE; [increment rear by 1]

2. cqueue[rear]=item;

3. end

2. deQueue(): This function is used to delete an element from the circular queue. In a circular queue, the element is always deleted from front position.

Algorithms for deleting an element from a circular queue:

This algorithm is assume that rear and front are initially set to MAZSIZE-1.

1. if (rear==front) [checking empty condition]

print Queue is empty and exit

2. front=(front+1)%MAXSIZE; [increment front by 1]

3. item=cqueue[front];

4. return item;

5. end.