Question

Write a C program to Delete a Tree.

I have written a small snippet of code to achieve this, but it goes into an infinite loop

void deleteTree(struct tnode *root)
{
 cout<<root->data<<endl;
 if( root->lchild == NULL && root->rchild == NULL)
   delete(root);

 deleteTree(root->lchild);
 deleteTree(root->rchild);
 //return root;
}  

I want to delete it while traversing. I know that Post Order Traversal can be used. But some other idea can be there or not?

Answer 1

Hint: Should you really call deleteTree(root->lchild); when there is no left child, or deleteTree(root->rchild); when there is no right child? How do you think that this is related to the infinite recursion?

Also: You should not delete the node first and then recurse into its children – because after the node has been deleted, it no longer exists, and you cannot really use root anymore (that it works for you is pure luck).