Question

CS 320: Test #2 Total 100 points 1177/2019 Name: Andjela Mihajlovic 1) You are given a Queue O n , and two pointer Q.tail and Q.head. The following ENQUEUE algorithm shows how to insert an element into Q. (20 points) ENQUEUE (Q,x) QIQ.tail] - x if Q.tail --Q.length tail-1 else Q.tail - Q.tail +1 and is full. (a) An overflow error occurs when you enqueue an element from Modify the given enqueue algorithm to detect an overflow. (b) Modify above ENQUEUE algorithm to write DEQUEUE algorithm which retrieves an element from the Q.

Answer 1

Answer(a)

Enqueue (Q, x)

{

//Queue Overflow Condition

if( Q.tail==Q.head)

{

PRINT(Queue Overflow)

exit(1)

}

Q[Q.tail]=x

if Q.tail==Q.length

Q.tail=1

else

Q.tail=Q.tail+1

}

Answer(b)

int Dequeue (Q)

{

//Queue Underflow Condition

if( Q.head== -1)

//because initially when no element is there in the queue, Q.head and Q.tail is set to -1

{

PRINT(Queue Underflow)

exit(1)

}

int a=Q[Q.head]

//condition for last element deletion

if(Q.head=Q.tail)

{

Q.head=-1

Q.tail= -1

}

else

{

Q.head=Q.head-1

}

}