# JavaScript Exercises: Count number of nodes in a Singly Linked List

## JavaScript Singly Linked List: Exercise-3 with Solution

Write a JavaScript program to create a singly linked list of n nodes and count the number of nodes.

Sample Solution:

JavaScript Code:

``````// Define a class representing a node in a singly linked list
class Node {
constructor(data) {
// Initialize the node with provided data
this.data = data
// Initialize the next pointer to null
this.next = null
}
}

// Define a class representing a singly linked list
constructor(Head = null) {
// Initialize the head of the list
}

// Method to add a new node to the end of the list
// Start traversal from the head node
let node = this.Head;
// If the list is empty, set the new node as the head and return
if(node == null){
return;
}
// Traverse the list until the last node
while (node.next) {
node = node.next;
}
// Set the next pointer of the last node to the new node
node.next = newNode;
}

// Method to count the number of nodes in the list
NodeCount() {
// Initialize a counter variable
let ctr = 0;
// Start traversal from the head node
let node = this.Head;
// Traverse the list and increment the counter for each node
while (node) {
ctr++;
node = node.next;
}
// Return the total count of nodes
return ctr;
}

// Method to display the elements of the list
displayList(){
// Start traversal from the head node
let node = this.Head;
// Initialize an empty string to store the elements of the list
var str = ""
// Traverse the list and concatenate each element to the string
while (node) {
str += node.data + "->";
node = node.next;
}
// Append "NULL" to indicate the end of the list
str += "NULL"
// Print the string containing the list elements
console.log(str);
}
}

// Create an instance of the SinglyLinkedList class
let numList = new SinglyLinkedList();
// Add nodes with data values to the list
// Display the original elements of the list
numList.displayList();
// Count the number of nodes in the list
var ctr = numList.NodeCount();
// Display the number of nodes in the list
console.log("Number of elements in the said Linked list: "+ctr)
```
```

Output:

```Original Linked list:
2->3->4->5->6->7->NULL
Number of elements in the said Linked list: 6
```

Flowchart:

Live Demo:

See the Pen javascript-singly-linked-list-exercise-3 by w3resource (@w3resource) on CodePen.

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Singly Linked List Previous: Print a singly linked list in reverse order.
Singly Linked List Next: Insert a new node at any position of a Singly Linked List.

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