Linked list traversal, visualized

class Node:
    def __init__(self, val):
        self.val = val
        self.next = None

head = Node(10)
head.next = Node(20)
head.next.next = Node(30)

curr = head
total = 0
while curr is not None:
    total += curr.val
    curr = curr.next

print(total)

#include <iostream>

struct Node {
    int val;
    Node* next;
    Node(int v) : val(v), next(nullptr) {}
};

int main() {
    Node* head = new Node(1);
    head->next = new Node(2);
    head->next->next = new Node(3);

    int sum = 0;
    for (Node* curr = head; curr != nullptr; curr = curr->next) {
        sum += curr->val;
    }

    std::cout << sum << std::endl;
    return 0;
}

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

        Node(int val) {
            this.val = val;
        }
    }

    public static void main(String[] args) {
        Node head = new Node(1);
        head.next = new Node(2);
        head.next.next = new Node(3);

        int sum = 0;
        for (Node curr = head; curr != null; curr = curr.next) {
            sum += curr.val;
        }

        System.out.println(sum);
    }
}