из Python в C++

[gio1592]

Я пытаюсь перевести етот код в C++ и у меня не выходит.... помогите plz

(Python)
class Node:		
	def __init__(self,initData,initPrevious = None,initNext = None):
		self.data = initData
		self.next = initNext
		self.previous = initPrevious
	def getData(self):
		return self.data
	def getNext(self):
		return self.next
	def getPrevious(self):
		return self.previous
	def setData(self,newdata):
		self.data = newdata
	def setNext(self,newnext):
		self.next = newnext
	def setPrevious(self,newprevious):
		self.previous = newprevious
		
	def __str__(self):
		return str(self.data)

вот файлы C++ :

Node.hpp

#ifndef NODE_HPP
#define NODE_HPP
#include <iostream>
using namespace std;

class Node
{
    public:
        Node();
        Node(int data,int previous,int next);

        double getData() const;
        double getNext() const;
        double getPrevious() const;
        void setData(int data);
        void setNext(int next);
        void setPrevious(int previous);

        friend std::ostream& operator <<(std::ostream&, const Node& data);



    private:
        int data,previous,next;
};

#endif // NODE_HPP

Node.cpp

#include "Node.hpp"
#include <iostream>
using namespace std;

Node::Node() : initData(0), initPrevious(0), initNext(0)
{}

Node::Node(int data,int previous,int next): data(initData),previous(initPrevious) ,next(initNext)
{}


double Node::getData() const
{
    return this->data;
}

double Node::getNext() const
{
    return this->next;
}

double Node::getPrevious() const
{
    return this->previous;
}

void Node::setData(int data)
{
    this-> initData=data;
}

void Node::setNext(int next)
{
    this->initNext=next;
}

void Node::setPrevious(int previous)
{
    this->initPrevious=previous;
}


std::ostream& operator <<(std::ostream& str, const Point& data)
{
    str << data;
    return str;
}