Question

Short Answers
Section 10.4
Tree
Traversals

9. Using the binary_tree_node from Section 10.3, Write a recursive function to meet the following specification. You do not need to check the precondition.

template <class Item>
void increase(binary_tree_node<Item>* root_ptr)
// Precondition: root_ptr is the root pointer of a binary tree.
// Postcondition: Every node of the tree has had its data increased by one.

10. Using the binary_tree_node from Section 10.3, write a recursive function to meet the following specification. You do not need to check the precondition.

template <class Item>
size_t many_nodes(binary_tree_node<Item>* root_ptr)
// Precondition: root_ptr is the root pointer of a binary tree.
// Postcondition: The return value is the number of nodes in the tree.
// NOTES: The empty tree has 0 nodes, and a tree with just a root has
// 1 node.

Answer 1

Code for Increasing the data value by one

void increase(binary_tree_node<Item>* root_ptr) {

if(root_ptr == NULL)

return;

else {

root_ptr->data = root_ptr->data+1;

increase(root_ptr->left);

increase(root_ptr->right);

}

}

Function to find the number of nodes in the tree

If the root is null then there are no nodes in the tree and we return 0.

If root is not null we initialize count to 1 and find the number of nodes in each sub tree recursively and add it to the count and finally return the total count.

size_t many_nodes(binary_tree_node<Item>* root_ptr) {

if(root_ptr == NULL)

return 0;

else {

size_t count = 1;

count+= many_nodes(root_ptr->left);

count+= many_nodes(root_ptr->right);

return count;

}