GENERIC QUEUE USING ARRAYLIST COLLECTION CLASS

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Wed May 29 2024 16:29:00 GMT+0000 (Coordinated Universal Time)

import java.util.*;
class GenQueueAL<T>{
	ArrayList<T> queue;
	GenQueueAL(ArrayList<T> queue){
		this.queue=queue;
	}
	void enqueue(T a){
			queue.add(a);
	}
	T dequeue(){
		T i= null;
		try{
			i= queue.remove(0);
		}catch(Exception e){
			i= null;
		}
		
		return i;
	}
	void display(){
		for(T i:queue){
			System.out.println(i);
		}
	}
	
	public static void main(String args[]){
		Scanner sc= new Scanner(System.in);
		ArrayList<Integer> a= new ArrayList<>();
		GenQueueAL<Integer> q1= new GenQueueAL<Integer>(a);
		int op=0;
		Integer ele;
		System.out.println("1.Enqueue\n2.Dequeue\n3.Display\n4.Exit");
		while(op!=4){
			
			System.out.print("Enter option: ");
			op=sc.nextInt();
			switch(op){
				case 1:
					System.out.println("enter element to enqueue: ");
					ele = sc.nextInt();
					q1.enqueue(ele);
					break;
				case 2:
					ele=q1.dequeue();
					if(ele==null){
						System.out.println("Queue is empty");
					}
					else{
						System.out.println("Dequeued element:"+ele);
					}
					break;
				case 3:
					q1.display();
					break;
				case 4:
					break;
				default :
					System.out.println("Enter valid option");
					
			}
		}
	}
		
		
	}

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