Recursive insertion and traversal linked list

We have discussed different methods of linked list insertion. How to recursively create a linked list?

Recursively inserting at the end:
To create a Linked list using recursion follow these steps. Below steps insert a new node recursively at the end of linked list.

// Function to insert a new node at the 
// end of linked list using recursion. 
Node* insertEnd(Node* head, int data) 
{ 
    // If linked list is empty, create a  
    // new node (Assuming newNode() allocates 
    // a new node with given data) 
    if (head == NULL)  
         return newNode(data); 
  
    // If we have not reached end, keep traversing 
    // recursively. 
    else 
        head->next = insertEnd(head->next, data); 
    return head; 
} 

Recursively traversing the list:
The idea is simple, we print current node and recur for remaining list.

void traverse(Node* head) 
{ 
    if (head == NULL) 
       return; 
      
    // If head is not NULL, print current node 
    // and recur for remaining list    
    cout << head->data << " "; 
  
    traverse(head->next); 
} 

Complete Program:
Below is complete program to demonstrate working of insert and traverse a linked list.

C++

// Recursive CPP program to recursively insert 
// a node and recursively print the list. 
#include <bits/stdc++.h> 
using namespace std; 
struct Node { 
    int data; 
    Node* next; 
}; 
  
// Allocates a new node with given data 
Node *newNode(int data) 
{ 
    Node *new_node = new Node; 
    new_node->data = data; 
    new_node->next = NULL; 
    return new_node; 
} 
  
// Function to insert a new node at the 
// end of linked list using recursion. 
Node* insertEnd(Node* head, int data) 
{ 
    // If linked list is empty, create a  
    // new node (Assuming newNode() allocates 
    // a new node with given data) 
    if (head == NULL)  
         return newNode(data); 
  
    // If we have not reached end, keep traversing 
    // recursively. 
    else 
        head->next = insertEnd(head->next, data); 
    return head; 
} 
  
void traverse(Node* head) 
{ 
    if (head == NULL) 
       return; 
      
    // If head is not NULL, print current node 
    // and recur for remaining list    
    cout << head->data << " "; 
  
    traverse(head->next); 
} 
  
// Driver code 
int main() 
{ 
    Node* head = NULL; 
    head = insertEnd(head, 6); 
    head = insertEnd(head, 8); 
    head = insertEnd(head, 10); 
    head = insertEnd(head, 12); 
    head = insertEnd(head, 14); 
    traverse(head); 
} 

Java

// Recursive Java program to recursively insert  
// a node and recursively print the list.  
class GFG 
{ 
      
static class Node  
{  
    int data;  
    Node next;  
};  
  
// Allocates a new node with given data  
static Node newNode(int data)  
{  
    Node new_node = new Node();  
    new_node.data = data;  
    new_node.next = null;  
    return new_node;  
}  
  
// Function to insert a new node at the  
// end of linked list using recursion.  
static Node insertEnd(Node head, int data)  
{  
    // If linked list is empty, create a  
    // new node (Assuming newNode() allocates  
    // a new node with given data)  
    if (head == null)  
        return newNode(data);  
  
    // If we have not reached end, keep traversing  
    // recursively.  
    else
        head.next = insertEnd(head.next, data);  
    return head;  
}  
  
static void traverse(Node head)  
{  
    if (head == null)  
    return;  
      
    // If head is not null, print current node  
    // and recur for remaining list  
    System.out.print( head.data + " ");  
  
    traverse(head.next);  
}  
  
// Driver code  
public static void main(String args[]) 
{  
    Node head = null;  
    head = insertEnd(head, 6);  
    head = insertEnd(head, 8);  
    head = insertEnd(head, 10);  
    head = insertEnd(head, 12);  
    head = insertEnd(head, 14);  
    traverse(head);  
}  
} 
  
// This code is contributed by andrew1234 

Python3

# Recursive Python3 program to  
# recursively insert a node and 
# recursively print the list. 
import math 
  
class Node:  
    def __init__(self, data):  
        self.data = data  
        self.next = None
  
# Allocates a new node with given data 
def newNode(data): 
    new_node = Node(data) 
    new_node.data = data 
    new_node.next = None
    return new_node 
  
# Function to insert a new node at the 
# end of linked list using recursion. 
def insertEnd(head, data): 
      
    # If linked list is empty, create a  
    # new node (Assuming newNode() allocates 
    # a new node with given data) 
    if (head == None): 
        return newNode(data) 
  
    # If we have not reached end,  
    # keep traversing recursively. 
    else: 
        head.next = insertEnd(head.next, data) 
    return head 
  
def traverse(head): 
    if (head == None): 
        return
      
    # If head is not None, print current node 
    # and recur for remaining list  
    print(head.data, end = " "); 
    traverse(head.next) 
  
# Driver code 
if __name__=='__main__':  
    head = None
    head = insertEnd(head, 6) 
    head = insertEnd(head, 8) 
    head = insertEnd(head, 10) 
    head = insertEnd(head, 12) 
    head = insertEnd(head, 14) 
    traverse(head) 
  
# This code is contributed by sapna singh 

C#

// Recursive C# program to recursively insert  
// a node and recursively print the list.  
using System;  
  
class GFG  
{  
      
public class Node  
{  
    public int data;  
    public Node next;  
};  
  
// Allocates a new node with given data  
static Node newNode(int data)  
{  
    Node new_node = new Node();  
    new_node.data = data;  
    new_node.next = null;  
    return new_node;  
}  
  
// Function to insert a new node at the  
// end of linked list using recursion.  
static Node insertEnd(Node head, int data)  
{  
    // If linked list is empty, create a  
    // new node (Assuming newNode() allocates  
    // a new node with given data)  
    if (head == null)  
        return newNode(data);  
  
    // If we have not reached end, keep traversing  
    // recursively.  
    else
        head.next = insertEnd(head.next, data);  
    return head;  
}  
  
static void traverse(Node head)  
{  
    if (head == null)  
    return;  
      
    // If head is not null, print current node  
    // and recur for remaining list  
    Console.Write(head.data + " ");  
  
    traverse(head.next);  
}  
  
// Driver code  
public static void Main(String []args)  
{  
    Node head = null;  
    head = insertEnd(head, 6);  
    head = insertEnd(head, 8);  
    head = insertEnd(head, 10);  
    head = insertEnd(head, 12);  
    head = insertEnd(head, 14);  
    traverse(head);  
}  
}  
  
// This code is contributed by 29AjayKumar 

Output:

6 8 10 12 14

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My Personal Notes

C++

Java

Python3

C#

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