using System;

public    class Program

    {

        public void Main(string[] args)

        {

            int[] arr = {1,2,3,4,5};

        }

​

        public static  Node<int> GetPrev(Node<int> firstNode, Node<int>pos)

        {

            Node<int> first= firstNode;

            Node<int> temp = pos;

            if(temp == first)

                return(null);

            while(first != null)

            {

                if(first.GetNext() == temp)

                {

                    return(first);

                }

            first = first.GetNext();

            }

            return(null);

        }

​

    }

​

​

​

   public class Node<T>

    {

        private T value;

        private Node<T> next;

​

        public Node(T value)

        {

            this.value = value;

            this.next = null;

        }

        public Node(T value, Node<T> next)

        {

            this.value = value;

            this.next = next;

        }

        public T GetValue()

        {

            return this.value;

        }

        public Node<T> GetNext()

        {

            return this.next;

        }

        public bool HasNext()

        {

            return (this.next != null);

        }

        public void SetValue(T value)

        {

            this.value = value;

        }

        public void SetNext(Node<T> next)

        {

            this.next = next;

        }

        public override string ToString()

        {

            return this.value.ToString() + " ";

        }

    }

​