Starting Out with C++: Early Objects - EEMB DERSLER

1120 Chapter 19 Binary Trees
• Inorder traversal
1. The node’s left subtree is traversed.
2. The node’s data is processed.
3. The node’s right subtree is traversed.
• Preorder traversal
1. The node’s data is processed.
2. The node’s left subtree is traversed.
3. The node’s right subtree is traversed.
• Postorder traversal
1. The node’s left subtree is traversed.
2. The node’s right subtree is traversed.
3. The node’s data is processed.
The IntBinaryTree class can display all the values in the tree using all three of these algorithms.
The algorithms are initiated by the following inline public member functions:
void showInOrder(void)
{ displayInOrder(root); }
void showPreOrder()
{ displayPreOrder(root); }
void showPostOrder()
{ displayPostOrder(root); }
Each of the public member functions calls a recursive private member function and passes the
root pointer as an argument. The recursive functions are very simple and straightforward:
void IntBinaryTree::displayInOrder(TreeNode *tree)
{
if (tree)
{
displayInOrder(tree->left);
cout value right);
}
}
void IntBinaryTree::displayPreOrder(TreeNode *tree)
{
if (tree)
{
cout value left);
displayPreOrder(tree->right);
}
}
void IntBinaryTree::displayPostOrder(TreeNode *tree)
{
if (tree)
{
displayPostOrder(tree->left);
displayPostOrder(tree->right);
cout value