Linked Structures

Traverse and Print

Walk from the head pointer to null, visiting each node exactly once without random indexing.

Algorithm

The replay labels nodes by value, such as node(20), and never exposes object identity or memory addresses. This Java DSA implementation uses the same small chain as the rest of the DSA track.

cursor A cursor reference names the node currently being visited.
null stop Traversal ends when the cursor reaches the null marker.

Basic Implementation

Basic.java
Replay: real traced execution (multi-file project)
public class Basic {
    static class Node {
        int value;
        Node next;
        Node(int value) { this.value = value; }
        Node(int value, Node next) { this.value = value; this.next = next; }
    }
    static String render(Node head) {
        StringBuilder out = new StringBuilder();
        Node cursor = head;
        while (cursor != null) {
            if (out.length() > 0) out.append(" -> ");
            out.append(cursor.value);
            cursor = cursor.next;
        }
        return out.append(" -> null").toString();
    }
    public static void main(String[] args) {
        Node head = new Node(10, new Node(20, new Node(30)));
        System.out.println(render(head));
    }
}

  1. head ← 10 -> 20 -> 30 -> null

    1public class Basic {2    static class Node {
    values this step10 -> 20 -> 30 -> nullhead

  2. output ← 10

    10Node cursor = head;11while (cursor != null) {12    if (out.length() > 0) out.append(" -> ");
    values this step10outputnode(10)cursor

  3. output ← 10 -> 20

    10Node cursor = head;11while (cursor != null) {12    if (out.length() > 0) out.append(" -> ");
    values this step10 -> 20outputnode(20)cursor

  4. output ← 10 -> 20 -> 30 -> null

    10Node cursor = head;11while (cursor != null) {12    if (out.length() > 0) out.append(" -> ");
    values this step10 -> 20 -> 30 -> nulloutputnode(30)cursor

  5. stdout ← 10 -> 20 -> 30 -> null

    19    Node head = new Node(10, new Node(20, new Node(30)));20    System.out.println(render(head));21}
    values this step10 -> 20 -> 30 -> nullstdout10 -> 20 -> 30 -> nulloutput

Complexity

  • Time: O(n)
  • Space: O(1)

Implementation notes

  • Keep the explicit node and pointer/reference operations; array shortcuts hide the linked-list state this lesson is meant to replay.
  • The final output prints the chain in a deterministic a -> b -> null form for cross-language comparison.