Problem 2, p 119. Similarly all the work for the circular queue is done in the addq() and deleteq() methods. Here’s the two methods with the code for printing error message when the queue is empty or full. You can also exit on error, but this makes it difficult to check the correctness of the code to add or delete.
void queue_full(){ printf(“The queue is Full \n”);}
void queue_empty(){ printf(“The queue is empty\n”);}
void addq(element item)
{/* add an item to the global queue front and rear mark the two queue ends */
if ((rear+1 == front) || ((rear == MAX_QUEUE_SIZE-1) && !front))
queue_full();
else {
queue[rear] = item;
rear = (rear+1) % MAX_QUEUE_SIZE;
}
}
element deleteq()
{/*delete and element from the circular queue */
int i;
element temp;
/* remove front element from the queue and put it in item */
if (front == rear) queue_empty();
else {
temp = queue[front];
front = (front+1) % MAX_QUEUE_SIZE;
return temp;
}
}
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