Chapter 12, Problem 12.16E

Program Plan Intro

Program plan:

1. item variable is used for input. There is structure Treenode having data, leftptr, rightptr member variables which represents the tree node.
2. void insertnode(node **ptr, char *value) function inserts the node in the tree.
3. void preorder(node *ptr) function displays the contents of the tree in a preorder fashion.
4. void inorder(node *ptr) function displays the contents of the tree in an in-order fashion.
5. void postorder(node *ptr) function display the contents of the tree in a post-order fashion.

Program description:

The main purpose of the program is to create a tree from the input entered by user. This violates the binary tree insertion rule and allows the user to enter the duplicate values as well. Then the created tree contents are displayed in preorder, inorder and postorder fashion.