Question

This all has to be in javascript

Use this linked list to answer the questions below:

var list = new LinkedList();

list.append(1);

list.append(2);

list.append(3);

list.append(4);

1. We are going to extend LinkedList with a sum method. As the name implies, all elements in the linked list should be summed together. First, write a few tests that will eventually show your code works correctly (after you implement the function in (2)). Note: see the LinkedList implementation above for more details. Hint: note that the sum of the elements in list above is 10.

2. Finish the implementation of the sum function below. As the name implies, all elements in the linked list should be summed together. Return null if there are no elements in the list. Make sure to validate your code using the tests from (1).

LinkedList.prototype.sum = function() {

note: use 'this' to refer to the linked list, e.g., this.getHead()

};

Answer 1

// User defined class node 
class Node { 
    
    // constructor 
    constructor(element) { 
        this.element = element; 
        this.next = null
    } 
    
} 


// linkedlist class 
class LinkedList { 
    
    constructor() { 
        this.head = null; 
        this.size = 0; 
    } 

    // append element at the end of list 
    append(element) { 
        // creates a new node 
        var node = new Node(element); 
    
        // to store current node 
        var current; 
    
        // if list is Empty add the 
        // element and make it head 
        if (this.head == null) 
                this.head = node; 
        else { 
                current = this.head; 
    
                // iterate to the end of the list
                while (current.next) { 
                        current = current.next; 
                } 
    
                // add node 
                current.next = node; 
        } 
        this.size++; 
    } 

    
}


// Extending LinkedList with sum method
class LinkedLists extends LinkedList {
    sum() {
        // To store sum
        var s = 0;
        
        // To store current node
        var current = this.head;
        
        if (current == null) {
            return null;
        }
        
        while (current) {
            s += current.element;
            current = current.next;
        }
    
        return s;
    }
}

var list = new LinkedLists();

console.log(list.sum())         // Output: null
list.append(1);          
console.log(list.sum())         // Output: 1
list.append(2);
console.log(list.sum())         // Output: 3
list.append(3);
console.log(list.sum())         // Output: 6
list.append(4);
console.log(list.sum())         // Output: 10

Go through this and let me know through comments if you have any doubts about this.

Please give a thumbs up if you are satisfied with the Answer.

Thank you!!!