Print Doubly Linked list in Reverse Order

Last Updated : 29 Jun, 2021

Given a doubly-linked list of positive integers. The task is to print the given doubly linked list data in reverse order.
Examples:

Input: List = 1 <=> 2 <=>  3 <=>  4 <=>  5
Output: 5  4  3  2  1

Input: 10 <=> 20 <=> 30 <=> 40
Output: 40  30  20  10

Approach:

Take a pointer to point to head of the doubly linked list.
Now, start traversing through the linked list till the end.
After reaching last node, start traversing in backward direction and simultaneously print the node->data.

Below is the implementation of the above approach:

C++

// C++ Program to print doubly
// linked list in reverse order
#include <bits/stdc++.h>
using namespace std;
 
// Doubly linked list node
struct Node {
    int data;
    struct Node* next;
    struct Node* prev;
};
 
// Function to print nodes of Doubly
// Linked List in reverse order
void reversePrint(struct Node** head_ref)
{
    struct Node* tail = *head_ref;
 
    // Traversing till tail of the linked list
    while (tail->next != NULL) {
        tail = tail->next;
    }
 
    // Traversing linked list from tail
    // and printing the node->data
    while (tail != *head_ref) {
        cout << tail->data << " ";
        tail = tail->prev;
    }
    cout << tail->data << endl;
}
 
/* UTILITY FUNCTIONS */
// Function to insert a node at the
// beginging of the Doubly Linked List
void push(struct Node** head_ref, int new_data)
{
    // allocate node
    struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));
 
    // put in the data
    new_node->data = new_data;
 
    // since we are adding at the beginning,
    // prev is always NULL
    new_node->prev = NULL;
 
    // link the old list off the new node
    new_node->next = (*head_ref);
 
    // change prev of head node to new node
    if ((*head_ref) != NULL)
        (*head_ref)->prev = new_node;
 
    // move the head to point to the new node
    (*head_ref) = new_node;
}
 
// Driver Code
int main()
{
    // Start with the empty list
    struct Node* head = NULL;
 
    // Let us create a sorted linked list
    // to test the functions
    // Created linked list will be 10->8->4->2
    push(&head, 2);
    push(&head, 4);
    push(&head, 8);
    push(&head, 10);
 
    cout << "Linked List elements in reverse order : " << endl;
 
    reversePrint(&head);
 
    return 0;
}

Java

// Java Program to print doubly
// linked list in reverse order
class Sol
{
 
// Doubly linked list node
static class Node
{
    int data;
    Node next;
    Node prev;
};
 
// Function to print nodes of Doubly
// Linked List in reverse order
static void reversePrint( Node head_ref)
{
    Node tail = head_ref;
 
    // Traversing till tail of the linked list
    while (tail.next != null)
    {
        tail = tail.next;
    }
 
    // Traversing linked list from tail
    // and printing the node.data
    while (tail != head_ref)
    {
        System.out.print( tail.data + " ");
        tail = tail.prev;
    }
    System.out.println( tail.data );
}
 
// UTILITY FUNCTIONS /
// Function to insert a node at the
// beginging of the Doubly Linked List
static Node push( Node head_ref, int new_data)
{
    // allocate node
    Node new_node = new Node();
 
    // put in the data
    new_node.data = new_data;
 
    // since we are adding at the beginning,
    // prev is always null
    new_node.prev = null;
 
    // link the old list off the new node
    new_node.next = (head_ref);
 
    // change prev of head node to new node
    if ((head_ref) != null)
        (head_ref).prev = new_node;
 
    // move the head to point to the new node
    (head_ref) = new_node;
    return head_ref;
}
 
// Driver Code
public static void main(String args[])
{
    // Start with the empty list
    Node head = null;
 
    // Let us create a sorted linked list
    // to test the functions
    // Created linked list will be 10.8.4.2
    head = push(head, 2);
    head = push(head, 4);
    head = push(head, 8);
    head = push(head, 10);
 
    System.out.print( "Linked List elements in reverse order : " );
 
    reversePrint(head);
}
}
 
// This code is contributed by Arnab Kundu

Python3

# Python3 Program to print doubly
# linked list in reverse order
import math
 
# Doubly linked list node
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None
 
# Function to print nodes of Doubly
# Linked List in reverse order
def reversePrint(head_ref):
    tail = head_ref
 
    # Traversing till tail of the linked list
    while (tail.next != None):
        tail = tail.next
 
    # Traversing linked list from tail
    # and pring the node.data
    while (tail != head_ref):
        print(tail.data, end = " ")
        tail = tail.prev
     
    print(tail.data)
 
# UTILITY FUNCTIONS
# Function to insert a node at the
# beginging of the Doubly Linked List
def push(head_ref, new_data):
     
    # allocate node
    new_node = Node(new_data)
 
    # put in the data
    new_node.data = new_data
 
    # since we are adding at the beginning,
    # prev is always None
    new_node.prev = None
 
    # link the old list off the new node
    new_node.next = head_ref
 
    # change prev of head node to new node
    if (head_ref != None):
        head_ref.prev = new_node
 
    # move the head to po to the new node
    head_ref = new_node
    return head_ref
 
# Driver Code
if __name__=='__main__':
     
    # Start with the empty list
    head = None
 
    # Let us create a sorted linked list
    # to test the functions
    # Created linked list will be 10.8.4.2
    head = push(head, 2)
    head = push(head, 4)
    head = push(head, 8)
    head = push(head, 10)
 
    print("Linked List elements in reverse order : ")
 
    reversePrint(head)
 
# This code is contributed by Srathore

C#

// C# Program to print doubly
// linked list in reverse order
using System;    
     
class Sol
{
 
// Doubly linked list node
public class Node
{
    public int data;
    public Node next;
    public Node prev;
};
 
// Function to print nodes of Doubly
// Linked List in reverse order
static void reversePrint( Node head_ref)
{
    Node tail = head_ref;
 
    // Traversing till tail of the linked list
    while (tail.next != null)
    {
        tail = tail.next;
    }
 
    // Traversing linked list from tail
    // and printing the node.data
    while (tail != head_ref)
    {
        Console.Write( tail.data + " ");
        tail = tail.prev;
    }
    Console.WriteLine( tail.data );
}
 
// UTILITY FUNCTIONS /
// Function to insert a node at the
// beginging of the Doubly Linked List
static Node push( Node head_ref, int new_data)
{
    // allocate node
    Node new_node = new Node();
 
    // put in the data
    new_node.data = new_data;
 
    // since we are adding at the beginning,
    // prev is always null
    new_node.prev = null;
 
    // link the old list off the new node
    new_node.next = (head_ref);
 
    // change prev of head node to new node
    if ((head_ref) != null)
        (head_ref).prev = new_node;
 
    // move the head to point to the new node
    (head_ref) = new_node;
    return head_ref;
}
 
// Driver Code
public static void Main(String []args)
{
    // Start with the empty list
    Node head = null;
 
    // Let us create a sorted linked list
    // to test the functions
    // Created linked list will be 10.8.4.2
    head = push(head, 2);
    head = push(head, 4);
    head = push(head, 8);
    head = push(head, 10);
 
    Console.Write( "Linked List elements in reverse order : " );
 
    reversePrint(head);
}
}
 
// This code contributed by Rajput-Ji

Javascript

<script>
 
      // JavaScript Program to print doubly
      // linked list in reverse order
      // Doubly linked list node
      class Node {
        constructor() {
          this.data = 0;
          this.next = null;
          this.prev = null;
        }
      }
 
      // Function to print nodes of Doubly
      // Linked List in reverse order
      function reversePrint(head_ref) {
        var tail = head_ref;
 
        // Traversing till tail of the linked list
        while (tail.next != null) {
          tail = tail.next;
        }
 
        // Traversing linked list from tail
        // and printing the node.data
        while (tail != head_ref) {
          document.write(tail.data + " ");
          tail = tail.prev;
        }
        document.write(tail.data + "<br>");
      }
 
      // UTILITY FUNCTIONS /
      // Function to insert a node at the
      // beginging of the Doubly Linked List
      function push(head_ref, new_data) {
        // allocate node
        var new_node = new Node();
 
        // put in the data
        new_node.data = new_data;
 
        // since we are adding at the beginning,
        // prev is always null
        new_node.prev = null;
 
        // link the old list off the new node
        new_node.next = head_ref;
 
        // change prev of head node to new node
        if (head_ref != null) head_ref.prev = new_node;
 
        // move the head to point to the new node
        head_ref = new_node;
        return head_ref;
      }
 
      // Driver Code
      // Start with the empty list
      var head = null;
 
      // Let us create a sorted linked list
      // to test the functions
      // Created linked list will be 10.8.4.2
      head = push(head, 2);
      head = push(head, 4);
      head = push(head, 8);
      head = push(head, 10);
 
      document.write("Linked List elements in reverse order : <br>");
 
      reversePrint(head);
       
    </script>

Output:

Linked List elements in reverse order : 
2 4 8 10

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