Page 91 - DCAP605_ADVANCED_DATA_STRUCTURE_AND_ALGORITHMS

Advanced Data Structure and Algorithms

Notes An implementation of the circular queue is shown below:

struct Cqueue
{
T data[n];
int front, rear;
}
void insert(queue q[], T x)
/* This procedure inserts an element x into the queue q */
{
q.rear = (q.rear + 1) % n;
if(q.rear == q.front)
printf(“Queue full”);
else
q.data[q.rear] = x;
}
void delete(queue q, T x)
/* deletes an element & stores it in x */
{
if(q.front == q.rear)
printf(“queue empty”);
else
{
x = q.data[q.front];
q.front =(q.front+ l) % n;
}
}
boolean empty(queue q[])
/* This function checks if the queue q is empty or not */
{
if(q.front == q.rear) return(true);
else return(false);
}
void initialize(queue q[])
/* This procedure initializes a queue q * /
{
q.front = 0;
q.rear = 0;
}
In this implementation, we are using only n-1 entries of the ‘elements’ array. To use all the

elements, a special flag has to be maintained to distinguish between the queue_full and queue_
empty situations.

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