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CSE143 Simple Binary Tree handout #23
Client Code IntTreeClient.java
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// Short program that demonstrates the use of the IntTree class.
public class IntTreeClient {
public static void main(String[] args) {
IntTree t = new IntTree(12);
System.out.println("Tree structure:");
t.printSideways();
System.out.println();
t.printPreorder();
t.printInorder();
t.printPostorder();
}
}
Log of Execution of IntTreeClient
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Tree structure:
7
3
6
12
1
11
5
10
2
9
4
8
preorder: 1 2 4 8 9 5 10 11 3 6 12 7
inorder: 8 4 9 2 10 5 11 1 12 6 3 7
postorder: 8 9 4 10 11 5 2 12 6 7 3 1
Class IntTreeNode.java
----------------------
// Class for storing a single node of a binary tree of ints
public class IntTreeNode {
public int data;
public IntTreeNode left;
public IntTreeNode right;
// constructs a leaf node with given data
public IntTreeNode(int data) {
this(data, null, null);
}
// constructs a branch node with given data, left subtree,
// right subtree
public IntTreeNode(int data, IntTreeNode left,
IntTreeNode right) {
this.data = data;
this.left = left;
this.right = right;
}
}
Class IntTree.java
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// Simple binary tree class that includes methods to construct a
// tree of ints, to print the structure, and to print the data
// using a preorder, inorder or postorder traversal. The trees
// built have nodes numbered starting with 1 and numbered
// sequentially level by level with no gaps in the tree. The
// documentation refers to these as "sequential trees."
public class IntTree {
private IntTreeNode overallRoot;
// pre : max > 0
// post: constructs a sequential tree with given number of
// nodes
public IntTree(int max) {
if (max <= 0) {
throw new IllegalArgumentException("max: " + max);
}
overallRoot = buildTree(1, max);
}
// post: returns a sequential tree with n as its root unless
// n is greater than max, in which case it returns an
// empty tree
private IntTreeNode buildTree(int n, int max) {
if (n > max) {
return null;
} else {
return new IntTreeNode(n, buildTree(2 * n, max),
buildTree(2 * n + 1, max));
}
}
// post: prints the tree contents using a preorder traversal
public void printPreorder() {
System.out.print("preorder:");
printPreorder(overallRoot);
System.out.println();
}
// post: prints in preorder the tree with given root
private void printPreorder(IntTreeNode root) {
if (root != null) {
System.out.print(" " + root.data);
printPreorder(root.left);
printPreorder(root.right);
}
}
// post: prints the tree contents using an inorder traversal
public void printInorder() {
System.out.print("inorder:");
printInorder(overallRoot);
System.out.println();
}
// post: prints in inorder the tree with given root
private void printInorder(IntTreeNode root) {
if (root != null) {
printInorder(root.left);
System.out.print(" " + root.data);
printInorder(root.right);
}
}
// post: prints the tree contents using a postorder traversal
public void printPostorder() {
System.out.print("postorder:");
printPostorder(overallRoot);
System.out.println();
}
// post: prints in postorder the tree with given root
private void printPostorder(IntTreeNode root) {
if (root != null) {
printPostorder(root.left);
printPostorder(root.right);
System.out.print(" " + root.data);
}
}
// post: prints the tree contents, one per line, following an
// inorder traversal and using indentation to indicate
// node depth; prints right to left so that it looks
// correct when the output is rotated.
public void printSideways() {
printSideways(overallRoot, 0);
}
// post: prints in reversed preorder the tree with given
// root, indenting each line to the given level
private void printSideways(IntTreeNode root, int level) {
if (root != null) {
printSideways(root.right, level + 1);
for (int i = 0; i < level; i++) {
System.out.print(" ");
}
System.out.println(root.data);
printSideways(root.left, level + 1);
}
}
}
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