#include <iostream>
// define binary tree structure and traverse helpers:
struct Node {
int value;
Node* left;
Node* right;
Node(int i=0) : value(i), left(nullptr), right(nullptr) {}
};
auto left = &Node::left;
auto right = &Node::right;
// traverse tree, using fold expression:
template<typename T, typename... TP>
Node* traverse (T np, TP... paths) { return (np ->* ... ->* paths);}
// np ->* paths1 ->* paths2 ...
int main()
{
// init binary tree structure:
Node* root = new Node{0};
root->left = new Node{1};
root->left->right = new Node{2};
// traverse binary tree:
Node* node = traverse(root, left, right);
std::cout << node->value;
}
