import java.io.*;
class Cqueue {
    int item[], f, r, size;
    public Cqueue(int x) {
        item = new int[x];
        f = r = -1;
        size = x;
    }
    public boolean isFull() {
        if ((f == 0 && r == size - 1) || (r == f - 1)) {
            return true;
        } else {
            return false;
        }
    }
    public boolean isEmpty() {

        if ((f == -1 && r == -1) || (r < f)) {
            return true;
        } else {
            return false;
        }
    }
    public void enqueue(int ele) {
        if (isFull()) {
            System.out.println("Queue is Full");
        } else {
            if (r == -1 && f == -1)
                f = r = 0;
            else
                r++;
            if (r == size)
                r = 0;
            item[r] = ele;
        }
    }
    public int dequeue() {
        if (isEmpty()) {
            System.out.println("Queue is empty");
            return (-1);
        } else {
            int x = item[f];
            f++;
            if (f == r + 1)
                f = r = -1;
            if (f == size) {
                f = 0;
            }
            return x;
        }
    }
    public int peek() {
        if (isEmpty()) {
            System.out.println("Queue is empty");
            return (-1);
        } else {
            return (item[f]);
        }
    }
    public void display() {
        if (isEmpty()) {
            System.out.println("Queue is empty");
        } else {
            int i = f, j = r;

            {
                while (i != j) {
                    System.out.print(item[i] + " ");
                    i++;
                    if (i == j) {
                        System.out.print(item[i]);
                    }
                    if (i == size) {
                        i = 0;
                    }
                }
            }

        }
    }
}
class Cqdemo {
    public static void main(String args[]) throws IOException {
        BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));
        int ch, ele, size;
        System.out.println("Enter size of queue");
        size = Integer.parseInt(obj.readLine());
        Cqueue c = new Cqueue(size);
        do {
            System.out.println("Menu");
            System.out.println("1.Add element in queue");
            System.out.println("2.Remove element from queue");
            System.out.println("3.Display element in queue");
            System.out.println("4.Peek element from queue");
            System.out.println("5.Exit");
            System.out.println("Enter choice");
            ch = Integer.parseInt(obj.readLine());
            switch (ch) {
                case 1:
                    {
                        System.out.println("Enter element :");
                        int x1 = Integer.parseInt(obj.readLine());
                        c.enqueue(x1);
                        break;
                    }
                case 2:
                    {
                        int x2 = c.dequeue();
                        System.out.println("Removed Element " + x2);
                        break;
                    }
                case 3:
                    {
                        c.display();
                        break;
                    }
                case 4:
                    {
                        int x3 = c.peek();
                        System.out.println("Peeked element" + x3);
                        break;
                    }
            }
        } while (ch != 5);
    }
}

/*
Enter size of queue

5
Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice

1
Enter element :

10
Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice

1
Enter element :

20
Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice

1
Enter element :

30
Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice

1
Enter element :

40
Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice

1
Enter element :

50
Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice

1
Enter element :

60
Queue is Full

Menu

1.Add element in queue

2.Remove element from queue

3.Display element in queue

4.Peek element from queue

5.Exit

Enter choice
2
Removed Element 10
Menu
1.Add element in queue
2.Remove element from queue
3.Display element in queue
4.Peek element from queue
5.Exit
Enter choice
2
Removed Element 20
Menu
1.Add element in queue
2.Remove element from queue
3.Display element in queue
4.Peek element from queue
5.Exit
Enter choice
3
30 40 50Menu
1.Add element in queue
2.Remove element from queue
3.Display element in queue
4.Peek element from queue
5.Exit
Enter choice
4
Peeked element30
Menu
1.Add element in queue
2.Remove element from queue
3.Display element in queue
4.Peek element from queue
5.Exit
Enter choice
5
Process Exit...

*/