Method enqueue

contents/data-structure/code/Queue/ArrayQueue.java:27–33

(E e)

    }

    @Override
    public void enqueue(E e) {
        if (size == data.length) throw new IllegalStateException("Queue is full");
        int avail = (front + size) % data.length;
        data[avail] = e;
        size ++;
    }

    @Override
    public E dequeue() {