Nodes

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We'll start with a really simple data structure. A Node is simple element that holds data and a pointer to another node. Here's a simple Java implementation of a Node:

class Node{
  int data;
  Node next;
  public Node(int d){
    data = d;
  }
}

Nodes are very simple, but form the basis of many data structures. We're about to use them in Lists, and later you can see how they're used in Trees.

Challenge

Given the above Node class, what will the following code print?

public class Main { 
    public static void main(String[] args) {
        Node a = new Node(1);
        Node b = new Node(2);
        Node c = new Node(3);
        a.next = b;
        b.next = c;
        System.out.println(a.next.next.data);
    }
}

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Comments

Bolke
Aug 1, 2:47 PM

I don't understand the class definition. What does the line

Node next;

mean?
Learneroo
Aug 2, 12:10 AM

Node is the name of the class (like Car or String). Each Node points to another Node called 'next' (though it could be called anything else as well).
Bolke
Aug 2, 9:22 AM

Thanks. I'll think about that...
Ryan Vergara
Nov 2, 7:19 AM

In JavaScript we can implement a Node as follows (highly similar in form as the one in the lesson):

class Node {
constructor(data){
this.data = data;

cont...
}
}

let a = new Node("A");
let b = new Node("B");
let c = new Node("C");

a.next = b;
b.next = c;

console.log(a.next.next.data) //will print out "C"

Notorious

Oct 15, 11:03 AM

A better implementation of the Node class.
class Node
{
private E element;
private Node next;
public Node(E element, Node next)

cont...

  {
     this.element = element;
      this.next = next;
  }
  public E getElement()
  {
     return this.element;
  }
  public Node<E> getNext()
  {
    return this.next;
  }
 public void setNext(Node<E> next)
{
   this.next = next;
}

}

Nodes

Challenge

Comments

Bolke

Learneroo

Bolke

Ryan Vergara

Notorious