errors for n-ary tree C++ - c++

Question

This is my first time working with any kind of tree. I created a tnode class for my tree and now I'm trying to create the class for the tree itself. However I've gotten a couple errors I can't figure out.
#ifndef Tree_Ntree_h
#define Tree_Ntree_h
// SIZE reprsents the max number of children a node can have
#define SIZE 10
// SEPERATE will allow the program to distinguish when a subtree no longer has children
#define SEPERATOR '#'
#include <iostream>
#include <fstream>
template <typename T>
class tnode{
public:
T value;
tnode *child[SIZE];
tnode() {};
tnode<T> *addChild(T data){
tnode*temp = new tnode;
temp -> value = data;
for (int i=0; i<SIZE; i++)
temp -> child[i] = NULL;
return temp;
}
};
template <typename T>
class Ntree{
private:
tnode<T> *root;
T data;
std::string filename;
public:
Ntree(){ root= NULL;}
Ntree( T data){ *root = data;}
inline T getRoot(){return root;}
My errors are in the last three lines.
In the last line of my code (getRoot), this is the error:
No viable conversion from 'tnode > *' to
'std::__1::basic_string'
In the second to last line and the third to last line (*root = data) (root = NULL) this is the error:
No viable overloaded '='
I don't understand why it is necessary to overload the = operator in this situation.

Answer 1

root is a tnode<T> * and getRoot is returning a T object. The compiler doesn't know how to convert one to the other. You probably just want to return root->value
However, you haven't allocated any space for root and it might be NULL, so you need to determine what to do when it is NULL.
In this line:
Ntree( T data){ *root = data;}
This time you are assigning a T to a tnode<T>, which the compiler doesn't know how to do. You also haven't allocated any memory for root. Instead you probably want todo something like:
Ntree( T data){ root = new T; root->value = data;}
Or better still have a tnode constructor that takes a value.