ql332

import java.util.Scanner;

import static java.lang.System.out;

class QueueLab3Pt2 {
    public static void main(String[] args) {
        MyQueue2 q= new MyQueue2();
        Scanner console = new Scanner(System.in);
        int choice;
        int number;
        out.println(q);
        while (true) {
            out.println("Enter 1 to enqueue, 2 to dequeue, 3 to stop");
            choice = console.nextInt();
            switch (choice) {
                case 3: System.exit(0);
                case 1: out.println("Enter the number to enqueue");
                    number = console.nextInt();
                    q.add(number);
                    q.display();
                    break;
                case 2: out.println(q.remove() + " is dequeued");
                    q.display();
                    break;
                case 4:out.println(q.getSize());
                    break;
                default: out.println("Invalid input");
            }
        }
    }
    }


class MyQueue2{
    private int[] list;
    private int front;
    private int back;
    private int capacity;
    private int size;


    private boolean isFull()
    {
        if (back -1  == front)
            return true;
        else
            return false;


    }

    private void resize()
    {

        int oldCapacity = capacity;
        capacity *= 2;
        int[ ] newItems = new int[capacity];
        for (int i=0; i<size; i++) {
            newItems[i] = list[front++];
            if (front == oldCapacity)
                front = 0;
        }
        list = newItems;
        front = 0;
        back = size - 1;
    }

    public MyQueue2() {
        list=new int[4];
        back=-1;
        front=0;
        size=0;
        capacity=4;

    }

    public boolean isEmpty()
    {
        return (size==0);
    }

    public void add(int item)
    {
        if (size == capacity)
            resize();

        size++;
        back = (back + 1)%capacity;
        list[back] = item;

    }

    public int remove() {
        if (size == 0) {
            out.println("Queue is empty");
            return -999;
        }
        int answer = list[front++];
        size--;
        if (size == 0) {
            front = 0;
            back = -1;

        }
        if (front == capacity)
            front = 0;
        return answer;
    }

    public int peek()
    {
        if(size==0){out.println("Queue is empty");return -999;}
        return list[front];

    }

    public int getSize()
    {


        return size;
    }

    public void display()
    {
        out.println(toString());

    }

    public String toString() {
        if (size == 0)
            return "[ ]" ;
        String answer = "[ ";
        int position = front;
        for (int i=0; i<size; i++) {
            answer += list[position++] + " ";
            if (position == capacity) position = 0;
        }
        return answer + "] ";
    }



}