package stackQueue;

/* Manually implement a queue of integers class */

public class QueueInt extends StackQueueInt {

/* Constructor for the QueueInt Class */

QueueInt() {

/* Create the superClass */

super();

/* Initialize the head and tail to be null */

head = null;

tail = null;

}

/* Add to the tail of the queue */

public void add(int newData) {

/* Create a new node for the data, and initialize with newData */

Node newNode = new Node(newData);

/* Do we have an empty queue? */

if (head == null) {

/* Queue was empty; so make the head and tail the new node */

head = newNode;

tail = newNode;

} else {

/* Add the new node to the tail */

tail.next = newNode;

tail = newNode;

}

}

/* Remove a node from the head of the queue */

public int remove() {

/* Is the queue empty? */

if (head == null) {

/* Throw an exception */

throw new IllegalStateException("Can't remove from an empty queue");

}

/* Store the item from the head of the queue */

int returnData = head.data;

/* Point the head at the next node */

head = head.next;

/* Have we reached the end of the queue? */

if (head == null) {

/* The queue is now empty, make sure the tail is set to null */

tail = null;

}

/* Return the data from the head of the queue */

return returnData;

}

}