Inorder tree traversal: Which definition is correct?

Question

I have the following text from an academic course I took a while ago about inorder traversal (they also call it pancaking) of a binary tree (not BST):

Answer 1

void
inorder (NODE root)
{
  if (root != NULL)
    {
      inorder (root->llink);
      printf ("%d\t", root->info);
      inorder (root->rlink);
    }
}

This the most simplest approach to recursive definition of in-order traversal, just call this function in the main function to get the in-order traversal of a given binary tree.

Answer 2

It is correct for preorder,nt for inorder

Answer 3

Forget the definitions, it's so much easier to just apply the algorithm:

void inOrderPrint(Node root)
{
  if (root.left != null) inOrderPrint(root.left);
  print(root.name);
  if (root.right != null) inOrderPrint(root.right);
}

It's just three lines. Rearrange the order for pre- and post- order.

Answer 4

I personally found this lecture quite helpful.

Answer 5

Hey according to me as mentioned in wiki is correct the sequence for a inorder traversal is left-root-right.

Till A, B, C, D, E, F i think you have understood already. Now after root F the next node is G that doesn't hav a left node but a right node so as per the rule (left-root-right) its null-g-right. Now I is the right node of G but I has a left node hence the traversal would be GHI. This is correct.

Hope this helps.

Answer 6

this may be late but it could be useful for anyone later .. u just need not to ignore the dummy or null nodes e.g the Node G has a left null node .. considering this null node will make every thing alright ..