Java Applets Centre

Cyclic Queue

Description
This applet demonstrates the basic operations on a cyclic queue data structure. The structure uses two pointers "Front" and "Rear" which are updated with insert/delete operations. Both "insert" and "delete" operations take O(1) time.

Insert: Inserts an element into the cyclic queue. This applet inserts a randomly generated value, when the "Insert" button is clicked.

Delete: Deletes an elament from the front of the queue, and re-adjusts the pointer "Front".

Front: Reads the value at the front of the queue.

Code (An array-based cyclic queue)

public void insert(int val){
if(qfull) return;
qempty=false;
tail=(tail+1)%n;
q[tail]=val;
if(head==((tail+1)%n))qfull=true;
}
public void delete(){
if(qempty) return;
qfull=false;
head=(head+1)%n;
if(head==((tail+1)%n))qempty=true;
}
public int front(){
return q[head];
}
public boolean isEmpty(){
return qempty;
}

Data Structures and Algorithms
Java Applets Centre

R. Mukundan
Department of Computer Science
University of Canterbury
Private Bag 4800, Christchurch
New Zealand.