Inorder traversal of binary tree using stack in c++

C++ program for Inorder traversal of binary tree using stack. Here problem description and explanation.

// Include header file
#include <iostream>

using namespace std;
// C++ program for
// Inorder traversal without recursion
// Using stack

// Binary Tree node
class TreeNode
{
	public: int data;
	TreeNode *left;
	TreeNode *right;
	// Make a tree node
	TreeNode(int data)
	{
		// Set node data
		this->data = data;
		this->left = nullptr;
		this->right = nullptr;
	}
};
class StackNode
{
	public: TreeNode *element;
	StackNode *next;
	StackNode(TreeNode *element)
	{
		this->element = element;
		this->next = nullptr;
	}
};
// Stack Class
class MyStack
{
	public: 
    StackNode *top;
	int size;
	MyStack()
	{
		this->top = nullptr;
		this->size = 0;
	}
	// Add new element into stack
	void push(TreeNode *element)
	{
		// Create new node
		StackNode *node = new StackNode(element);
		node->next = this->top;
		// new node is new top
		this->top = node;
		// Increase the size
		this->size += 1;
	}
	// Remove top element of the stack
	void pop()
	{
		if (this->top != nullptr)
		{
			// next node is new top
			this->top = this->top->next;
			// Reduce size
			this->size -= 1;
		}
	}
	// Returns the status of empty or non empty stacks
	bool isEmpty()
	{
		if (this->size > 0 && this->top != nullptr)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	// Return top element of stack
	TreeNode *peek()
	{
		if (this->isEmpty())
		{
			return nullptr;
		}
		return this->top->element;
	}
};
class BinaryTree
{
	public: TreeNode *root;
	BinaryTree()
	{
		this->root = nullptr;
	}
	// Display Inorder view of binary tree
	void inorder()
	{
		if (this->root != nullptr)
		{
			// Make new stack
			MyStack *s = new MyStack();
			TreeNode *node = this->root;
			// Display tree element
			while (!s->isEmpty() || node != nullptr)
			{
				if (node != nullptr)
				{
					// Add current node
					s->push(node);
					// Visit to left subtree
					node = node->left;
				}
				else
				{
					// When node is null
					// Get stack top element
					node = s->peek();
					// Display node value
					cout << " " << node->data;
					// Remove top element of the stack
					s->pop();
					// Visit to left subtree of current node
					node = node->right;
				}
			}
		}
		else
		{
			cout << "Empty Linked List\n";
		}
	}
};
int main()
{
	// Create new tree
	BinaryTree *tree = new BinaryTree();
	/*
	    Construct Binary Tree
	    -----------------------
	        15
	       /  \
	      24   54
	     /    /  \
	    35   62   13
	*/
	// Add tree nodes
	tree->root = new TreeNode(15);
	tree->root->left = new TreeNode(24);
	tree->root->right = new TreeNode(54);
	tree->root->right->right = new TreeNode(13);
	tree->root->right->left = new TreeNode(62);
	tree->root->left->left = new TreeNode(35);
	// Display result
	tree->inorder();
	return 0;
}

Output

 35 24 15 62 54 13