In the enqueue(int x) function of Queue.java, we do not check if the queue is already full. Implement the capacity check feature for enqueue(int x). (Hint: Use System.err.println() to print the error message.)

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package ds;

public class Queue {

public int size;

public int[] array;

public int head;

public int tail;

public Queue() {

size = 0;

array = null;

head = 0;

tail = 0;

}

public Queue(int _size) {

size = _size;

array = new int[size];

head = 0;

tail = 0;

}

/*

* Implement the ENQUEUE(Q, x) function

*/

public boolean IsEmpty() {

return (head == 0 && tail == 0);

}

public void enqueue(int x) {

int no;

if (tail == array.length && head == 0)

System.out.println("queue is full");

else {

array[tail] = x;

tail++;

}

}

/*

* Implement the DEQUEUE(Q) function

*/

public int dequeue() {

int num = -1;

if (IsEmpty())

System.out.println("queue is empty");

else {

num = array[head];

head++;

}

return num;

}

/*

* Convert queue to string in the format of #size, head, tail, [#elements]

*/

public String toString() {

String str;

str = size + ", " + head + ", " + tail + ", [";

for (int i = head; i % size < tail; i++)

str += array[i] + ",";

str += "]";

return str;

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

Queue q;

q = new Queue(10);

for (int i = 0; i < 5; i++)

q.enqueue(i);

System.out.println(q.toString());

for (int i = 0; i < 2; i++)

q.dequeue();

System.out.println(q.toString());

}

}