Binary Tree Node Structure in DSA C++ - Execution Trace

Concept Flow - Binary Tree Node Structure

Create new node

↓

Assign data value

↓

Set left child pointer to null

↓

Set right child pointer to null

↓

Node ready for linking in tree

This flow shows how a binary tree node is created with data and two child pointers initialized to null.

Execution Sample

DSA C++

struct Node {
  int data;
  Node* left;
  Node* right;
  Node(int val) : data(val), left(nullptr), right(nullptr) {}
};

Defines a binary tree node with an integer data and pointers to left and right children initialized to null.

Execution Table

Step	Operation	Node Data	Left Pointer	Right Pointer	Visual State
1	Create node with data 10	10	null	null	┌────────┐ │ data:10│ │ left:∅ │ │ right:∅│ └────────┘
2	Left pointer set to null	10	null	null	┌────────┐ │ data:10│ │ left:∅ │ │ right:∅│ └────────┘
3	Right pointer set to null	10	null	null	┌────────┐ │ data:10│ │ left:∅ │ │ right:∅│ └────────┘
4	Node ready for linking	10	null	null	┌────────┐ │ data:10│ │ left:∅ │ │ right:∅│ └────────┘

💡 Node created with data 10 and both child pointers set to null, ready to be linked in a binary tree.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
data	undefined	10	10	10	10
left	undefined	null	null	null	null
right	undefined	null	null	null	null

Key Moments - 2 Insights

Why are left and right pointers set to null initially?

Because in the execution_table rows 2 and 3, both pointers are set to null to indicate the node has no children yet.

What does the visual state represent in each step?

It shows the node's data and the current state of its left and right pointers, which remain null until linked.

Visual Quiz - 3 Questions

Look at the execution_table at step 1, what is the value of the node's data?

A null

B 10

C undefined

D 0

💡 Hint

Check the 'Node Data' column in execution_table row with Step 1.

At which step are the left and right pointers both set to null?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the 'Left Pointer' and 'Right Pointer' columns in execution_table rows.

If the right pointer was not set to null, what would the visual state show at step 3?

A right:∅

B right:undefined

C right:some garbage value

D right:null

💡 Hint

Pointers not initialized usually contain garbage values in memory before assignment.

Concept Snapshot

Binary Tree Node Structure:
- Each node holds data and two pointers: left and right.
- Pointers start as null (no children).
- Node created with constructor initializing data and pointers.
- Ready to link nodes to form a tree.

Full Transcript

This concept shows how to create a binary tree node in C++. The node has an integer data field and two pointers for left and right children. When a node is created, its data is set to the given value, and both pointers are set to null, meaning it has no children yet. The visual state shows the node as a box with data and pointers labeled. This node can then be linked to other nodes to build a binary tree.