节点插入二叉树C ++

Question

I believe i implemented inserting a new node into a binary search tree, however my testing script shows my tree as being in valid

My code where the value is inserted into the tree if there is no current node.

bool InsertRecursive(BinaryTreeNode* tree_node, int value) {

 if (tree_node == NULL)
 {

BinaryTreeNode * pNode = new BinaryTreeNode;
pNode->data = value;   // inserting node in
pNode->left_child = NULL;
pNode->right_child = NULL;
tree_node = pNode ; 
return true;
 }
       if(tree_node->data == value )   // if value already exists return false
{
 return false ; 
  }
   else if (tree_node->data > value)   // traverses to find the location for the value
    return InsertRecursive(tree_node->right_child, value);
  else 
return InsertRecursive(tree_node->left_child, value);

 }

the actual method of inserting the node inside

 bool BinaryTree::Insert(int value) {

if (InsertRecursive(head, value)) {
return true;
} else
  return false;
}

What my testing script says

| Test: Insert

| | -Should be a valid tree of size 1 after inserting '4'

| | | You built an invalid tree. Why would you do that to me?

| | -Should be a valid tree of size 2 after inserting '2'

| | | You built an invalid tree. Your code needs to get it's life together

| | -Should be a valid tree of size 3 after inserting '3'

| | | You built an invalid tree. More coffee maybe?

| | -Insert(1) should return false for: [ d2-1 d1-2 d2-3 d0-4 d2-5 d1-6 d2-7

] | | | It returned true. Unlike a boss | Failed!

So the problem should be with in where i actually insert the node as the tree is being read as in valid. I am lost on how to solve this however and would like some guidance.

Answer 1

when leave fuction, "tree_node = pNode ;" effect nothing. change tree_node type to "BinaryTreeNode**" if you want change it's value

Answer 2

You have to split the inserts into both the helper and the method for each case of when head is equal to nullptr and when tree_node is equal to nullptr . Then add your implementations to both of those.

Your insert functions look like they are are on the right track so just think about how the two functions in the helper and the method are similar.