package leon.datastructure.queue;

public class Queue {

private int front;

private int back;

private int size;

private Object[] elements;

public Queue() {

elements = new Object[10];

}

public int getSize() {

return size;

}

public Object deQueue() {

Object o = null;

if (size > 0) {

size--;

o = elements[front];

elements[front] = null;

front = (front > elements.length - 1) ? 0 : front + 1;

}

return o;

}

public void enQueue(Object o) {

if (size >= elements.length) {

Object[] newElements = new Object[elements.length * 2];

for (int i = 0; i < elements.length; ++i) {

newElements[i] = elements[i];

}

elements = newElements;

}

elements[back] = o;

back++;

size++;

}

public String toString() {

StringBuffer str = new StringBuffer();

for (int i = 0; i < elements.length; i++) {

Object o = elements[i];

if (o != null) {

str.append(o + " ");

}

}

return str.toString();

}

}