Queue

import java.io.*;
import java.util.*;

class dataqueue {
	public static void main(String args[]) {
		Queue queue = new LinkedList();
		Scanner scan = new Scanner(System.in);
		int opt = 0;
		while(opt != 4) {
			System.out.println("1. Enqueue 2. Dequeue 3. Display 4. Exit");
			System.out.println("Enter your choice:");
			opt = Integer.parseInt(scan.nextLine());
			switch(opt) {
				case 1:
					System.out.println("Please Enter Value in Queue:");

					/* Enqueue data in Queue */
					if(queue.offer(scan.nextLine()))
						System.out.println("Data enqueued successfully!");
					break;
				case 2:

					/* Dequeue data in Queue */
					System.out.println(queue.poll()+" - dequeued successfully!");
					break;
				case 3:
					System.out.println("Queue:");
					System.out.println(queue);
					break;
				case 4:
					System.out.println("Bye Bye!");
					System.exit(0);
					break;
				default:
					System.out.println("Invalid choice!");
			}
		}
	}
}


/****** Output ******/
1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

1

Please Enter Value in Queue:

5

Data enqueued successfully!

1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

1

Please Enter Value in Queue:

6

Data enqueued successfully!

1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

1

Please Enter Value in Queue:

7

Data enqueued successfully!

1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

1

Please Enter Value in Queue:

8

Data enqueued successfully!

1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

3

Queue:

[5, 6, 7, 8]

1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

2

5 - dequeued successfully!

1. Enqueue 2. Dequeue 3. Display 4. Exit

Enter your choice:

4

Bye Bye!