**Using recursion:-**Below is sample code line which calculates length of list recursively(Download complete sample program).

`/* length of list by iterating list recursively */`

public static int findLengthOfListRecursion(Node head) {

int length = 0;

/* If list is empty or we have reached at end of list */

if (head == null)

return 0;

else

/* call this method again with next node */

length = 1 + findLengthOfListRecursion(head.getNext());

return length;

}

**Using Iterative approach :-**Below is sample code line which calculates length of list by traversing list (Download complete sample program).

`/* length of list by iterating list */`

public static int findLengthOfListIterative(Node head) {

int length = 0;

/* If list is empty, return length is 0 */

if (head == null) {

return length;

} else {

Node current = head;

/* Iterate list and increment length for each node */

while (current != null) {

length += 1;

current = current.getNext();

}

}

return length;

}

Below is the complete sample program for the length calculation using recursion and iterative approach:-

public class LengthOfLinkedlist {

static Node head;

/* length of list by iterating list recursively */

public static int findLengthOfListRecursion(Node head) {

int length = 0;

/* If list is empty or we have reached at end of list */

if (head == null)

return 0;

else

/* call this method again with next node */

length = 1 + findLengthOfListRecursion(head.getNext());

return length;

}

/* length of list by iterating list */

public static int findLengthOfListIterative(Node head) {

int length = 0;

/* If list is empty, return length is 0 */

if (head == null) {

return length;

} else {

Node current = head;

/* Iterate list and increment length for each node */

while (current != null) {

length += 1;

current = current.getNext();

}

}

return length;

}

/* Add New node at start of linked list */

private static void insertFirst(int data) {

Node newNode = createNewNode(data);

if (head == null) {

head = newNode;

} else {

newNode.setNext(head);

head = newNode;

}

}

private static Node createNewNode(int data) {

return new LengthOfLinkedlist().new Node(data);

}

class Node {

private int data;

private Node next; // reference(handler) for next Node.

public Node(int data) {

this.data = data;

this.next = null;

}

public Node getNext() {

return next;

}

public void setNext(Node next) {

this.next = next;

}

public int getData() {

return data;

}

}

public static void main(String[] args) {

/* Setup a linked list */

insertFirst(142);

insertFirst(135);

insertFirst(141);

insertFirst(141);

insertFirst(145);

insertFirst(148);

insertFirst(145);

/* Find length of linked list using recursive call */

int length = LengthOfLinkedlist.findLengthOfListRecursion(head);

System.out.println("length of list(recursion) : " + length);

/* Find length of linked list using recursive call */

int length2 = LengthOfLinkedlist.findLengthOfListIterative(head);

System.out.println("length of list(Iterative) : " + length2);

}

}

length of list(recursion) : 7

length of list(Iterative) : 7

==========================

**Some other linked list problems that use linked list iteration / length of linked list, try following questions:- **

1. Find **sum**of all elements of linked list.

2. Find

**mean**of linked list, provided data is of number type.

3. Count number of

**odd and even numbers**in the given linked list.

4. Find

**middle element**of the linked list.(For even # of elements first node the two middle node is mean)

5. Check whether the given

**linked list is palindrome or not**.

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