TreeShared.cpp

//
//  main.cpp
//  TreeShared
//
//  Created by stan on 12/8/17.
//  Copyright © 2017 stan. All rights reserved.
//

#include <iostream>

template <class T> class Tree;

template <class T>
class Node
{
public:
    Node(const T& v)
    : value(v)
    {}
    
    ~Node() {
        for (Node *child = _children, *nxt; child; child = nxt) {
            nxt = child->_next;
            delete child;
        }
    }
    
    Node *_parent = nullptr, *_next = nullptr, *_children = nullptr;
    Tree<T> *_root;
    T value;
    
    std::shared_ptr<Node> insert(const T& v) {
        Node *n = new Node(v);
        n->_next = _children;
        n->_parent = this;
        n->_root = _root;
        _children = n;
        
        return std::shared_ptr<Node<T>>(root(), n);
    }
    
    std::shared_ptr<Tree<T>> root()
    {
        return _root->shared_from_this();
    }
    
    std::shared_ptr<Tree<T>> parent()
    {
        if (_parent) {
            return std::shared_ptr<Node<T>>(root(), _parent);
        }
        return {};
    }
    
    std::shared_ptr<Tree<T>> children()
    {
        if (_children) {
            return std::shared_ptr<Node<T>>(root(), _children);
        }
        return {};
    }
    
    std::shared_ptr<Tree<T>> next()
    {
        if (_next) {
            return std::shared_ptr<Node<T>>(root(), _next);
        }
        return {};
    }
    
    void print(const std::string &prefix = "")
    {
        std::cout << prefix << value << '\n';
        for (Node *child = _children; child; child = child->_next) {
            child->print(prefix + "  ");
        }
    }
};

template <class T>
class Tree: public Node<T>, public std::enable_shared_from_this<Tree<T>>
{
public:
    Tree(const T& v)
    : Node<T>(v)
    {
        Node<T>::_root = this;
    }

    ~Tree()
    {
        std::cout << "deleted\n";
    }
    
    static std::shared_ptr<Tree<T>> create(const T &v)
    {
        return std::make_shared<Tree>(v);
    }
};

int main(int argc, const char * argv[]) {
    
    auto t = Tree<int>::create(1);
    t->insert(2);
    auto n = t->insert(3);
    t->insert(4);
    n->insert(5);
    t = nullptr;
    n->root()->print();
    return 0;
}