Check for continuous binary tree in c++

C++ program for Check for continuous binary tree. Here more information.

// Include header file
#include <iostream>
using namespace std;
/*
  C++ program for
  Check if binary tree is continuous tree
  Using recursion
*/
// Binary Tree Node
class TreeNode
{
	public: 
    int data;
	TreeNode *left;
	TreeNode *right;
	TreeNode(int data)
	{
		// Set node value
		this->data = data;
		this->left = nullptr;
		this->right = nullptr;
	}
};
class BinaryTree
{
	public: 
    TreeNode *root;
	BinaryTree()
	{
		this->root = nullptr;
	}
	int absValue(int num)
	{
		if (num < 0)
		{
			return -num;
		}
		return num;
	}
	// Check tree is continuous or not
	bool isContinuous(TreeNode *node)
	{
		if (node != nullptr)
		{
			if ((node->left != nullptr && 
                 this->absValue(node->data - node->left->data) != 1) || 
                (node->right != nullptr && 
                 this->absValue(node->data - node->right->data) != 1))
			{
				// Case
				// When fail continuous tree rule
				return false;
			}
			if (this->isContinuous(node->left) && 
                this->isContinuous(node->right))
			{
				return true;
			}
			// When node value is not satisfied 
            // continuous tree properties
			return false;
		}
		return true;
	}
};
int main()
{
	// Create new tree
	BinaryTree *tree = new BinaryTree();
	/*
	   Binary Tree
	   ------------
	       5
	     /   \
	    4     4
	   /     /  \
	  3     5    3
	   \
	    2
	        
	*/
	// Add tree node
	tree->root = new TreeNode(5);
	tree->root->left = new TreeNode(4);
	tree->root->right = new TreeNode(4);
	tree->root->left->left = new TreeNode(3);
	tree->root->right->right = new TreeNode(3);
	tree->root->right->left = new TreeNode(5);
	tree->root->left->left->right = new TreeNode(2);
	if (tree->isContinuous(tree->root) == true)
	{
		cout << "Continuous Tree " << endl;
	}
	else
	{
		cout << "Not Continuous Tree " << endl;
	}
	// Case 2
	/*
	       5
	     /   \
	    4     4
	   /     /  \
	  3     5    3
	   \
	    1  <--- change value
	        
	*/
	tree->root->left->left->right->data = 1;
	if (tree->isContinuous(tree->root) == true)
	{
		cout << "Continuous Tree " << endl;
	}
	else
	{
		cout << "Not Continuous Tree " << endl;
	}
	return 0;
}

Output

Continuous Tree
Not Continuous Tree