Binary Tree (Not Binary Search Tree) Creating New Node and Children

Question

I am trying to implement a method to create a node to insert into a binary tree (not bst).

struct node{
       struct node *left;
       int data;
       struct node *right;
};

typedef struct node *n;

void createNewNode() {

     char r; // stands for response (whether or not a left or right child should be created)
     int d; //data to be stored in a node

     n newnode = new(struct node); //creates a new node

     cout<<"Enter data for the new node:"<<endl;
     cin>>d;
     newnode->data = d;

     cout<<"any left child? y/n"<<endl;
     cin>>r;
     switch (r) {
            case 's':
                 createNewNode(); // I thought to make it recursive and if a child is going to be created, then the method will call itself all over again
                 break;

            case 'n':
                 newnode->left = NULL; // if child is not created then pointer is NULL
                 break;
            }

     cout<<"any right child? y/n"<<endl;
     cin>>r;
     switch (r) {
            case 's':
                 createNewNode(); //recursive method again
                 break;

            case 'n':
                 newnode->right = NULL; // if child is not created then pointer is NULL
                 break;
            }
}

The problem that I am facing is when I use the recursive method to create a left or right child. I think it is not pointing to a value for the parent node created first. Am I right or wrong? I guess the question is whether or not I am linking the parent node to the right or left child node with the method I am trying to implement.

Answer 1

In createNewNode() function, you just create a new node and leave it without relating them to each other! You should bind it to left or right pointer.

This is what you should do:

1. Change the output of this function from void to n
2. At the end of function return the newly created node
3. In both of the switch statements, where you call the function recursively, assign output of the function call to newnode->left or newnode->right accordingly.