JavaScript Program to Print Positive Numbers in a Linked List

This JavaScript program aims to print positive numbers present in a linked list. A linked list is a data structure consisting of a sequence of elements, where each element points to the next element in the sequence.

The program traverses the linked list and prints all the positive numbers encountered.

Iterative Approach

In this method, we will traverse the linked list using a loop, checking each element if it is positive, and printing it if so.

Example: The below example prints positive numbers in a linked list in JavaScript.

Javascript

class Node {
    constructor(value) {
        this.value = value;
        this.next = null;
    }
}

function createLinkedList(arr) {
    if (arr.length === 0) {
        return null;
    }

    let head = new Node(arr[0]);
    let current = head;

    for (let i = 1; i < arr.length; i++) {
        current.next = new Node(arr[i]);
        current = current.next;
    }

    return { head };
}


function printPositiveNumbersIterative(head) {
    let current = head;
    while (current !== null) {
        if (current.value > 0) {
            console.log(current.value);
        }
        current = current.next;
    }
}
const linkedList =
    createLinkedList([-1, 2, -3, 5, 4, -5]);
printPositiveNumbersIterative(linkedList.head);

Output

2
5
4

Recursive Approach

Implement a recursive function to traverse the linked list, checking each element recursively and printing the positive numbers encountered.

Example: The below example is to print positive numbers in a linked list in JavaScript.

Javascript

class Node {
    constructor(value) {
        this.value = value;
        this.next = null;
    }
}

function createLinkedList(arr) {
    if (arr.length === 0) {
        return null;
    }

    let head = new Node(arr[0]);
    let current = head;

    for (let i = 1; i < arr.length; i++) {
        current.next = new Node(arr[i]);
        current = current.next;
    }

    return { head };
}

function printPositiveNumbersRecursive(node) {
    if (node === null) {
        return;
    }
    if (node.value > 0) {
        console.log(node.value);
    }
    printPositiveNumbersRecursive(node.next);
}
const linkedList =
    createLinkedList([-1, 2, 5, -3, 4, -5]);
printPositiveNumbersRecursive(linkedList.head);

Output

2
5
4