Question

using java

Consider the following LinkedList that is composed of 4 nodes containing 13, 7, 24, 1. Assume that the Node.value is an int, and the reference to the first value is a Node called n. Write a method that computes the sum of all the values in the nodes of a linked list. For example, your method shall return the sum of all the nodes, in this example shall return 45

Answer 1

Below is code for method which returns sum of all nodes in java.

   public int sumOfAllNodes() {
        Node cur = head;
        int sum = 0;
        while(cur != null) 
        {  
            sum = sum + cur.value;
            cur = cur.next;
        }
        return sum;
    }

Below is whole code.

public class Main {
    static class Node {
        int value;
        Node next;

        public Node(int a) {
            value = a;
            next = null;
        }
    }

    Node head; // tail

    public Main() {
        head = null; 
    }

    public void insertFirst(int a) {
        Node newNode = new Node(a);
        newNode.next = head;
        head = newNode;
        // if (tail == null) tail = newNode;
    }


    
    public int sumOfAllNodes() {
        Node cur = head;
        int sum = 0;
        while(cur != null) 
        {  
            sum = sum + cur.value;
            cur = cur.next;
        }
        return sum;
    }

public String toString() {
        if (head == null) return "The list is empty.";
        StringBuilder sb = new StringBuilder();
        sb.append(head.value);
        Node cur = head.next;
        while ( cur != null ) {
            sb.append(" -> " + cur.value);
            cur = cur.next;
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        Main list = new Main();
        list.insertFirst(1);
        list.insertFirst(24);
        list.insertFirst(7);
        list.insertFirst(13);
        System.out.println(list);
        int sum = list.sumOfAllNodes();
        System.out.println(sum);

    }
}

Output: