Chapter 12, Problem 12.24E

(Printing Trees) Write a recursive function outputTree to display a binary tree on the screen. The function should output the tree row-by-row with the top of the tree at the left of the screen and the bottom of the tree toward the right of the screen. Each row is output vertically. For example, the binary tree illustrated in Fig12.22. is output as follows:

Note that the rightmost leaf node appears at the top of the output in the rightmost column, and the root node appears at the left of the output. Each column of output starts five spaces to the right of the previous column. Function outputTree should receive as arguments a pointer to the root node of the tree and an integer totalSpaces representing the number of spaces preceding the value to be output (this variable should start at zero so that the root node is output at the left of the screen). The function uses a modified inorder traversal to output the tree. The algorithm is as follows:

While the pointer to the current node is not NULL.

Recursively call outputTree with the current node’s right subtree and totalSpaces + 5.

Use a for statement to count from 1to totalSpaces Output the value in the current node.

Recursively call outputTree with the current nodes left subtree and totalSpaces + 5.