首先用Node类定义一个节点，用来存储每个节点的内容：
public class Node {
// 关键字
private int keyData;
// 其他数据
private int otherData;
// 左子节点
private Node leftNode;
// 右子节点
private Node rightNode;
public Node(int keyData, int otherDate) {
this.keyData = keyData;
this.otherData = otherDate;
}
public int getKeyData() {
return keyData;
}
public void setKeyData(int keyData) {
this.keyData = keyData;
}
public Node getLeftNode() {
return leftNode;
}
public void setLeftNode(Node leftNode) {
this.leftNode = leftNode;
}
public int getOtherData() {
return otherData;
}
public void setOtherData(int otherData) {
this.otherData = otherData;
}
public Node getRightNode() {
return rightNode;
}
public void setRightNode(Node rightNode) {
this.rightNode = rightNode;
}
// 显示方法
public void display(){
System.out.println(keyData + "," + otherData);
}
}
然后定义一个Tree类，并用前序遍历、中序遍历和后序遍历
public class Tree {
// 根
private Node root;
// 插入方法
public void insert(int keyData, int otherData) {
Node newNode = new Node(keyData, otherData);
// 如果说没有节点
if (root == null) {
root = newNode;
} else {
Node current = root;
Node parent;
while (true) {
parent = current;
if (keyData < current.getKeyData()) {
current = current.getLeftNode();
if (current == null) {
parent.setLeftNode(newNode);
return;
}
} else {
current = current.getRightNode();
if (current == null) {
parent.setRightNode(newNode);
return;
}
}
}
}
}
// 查找方法
public Node find(int keyData) {
Node current = root;
while (current.getKeyData() != keyData) {
if (keyData < current.getKeyData()) {
current = current.getLeftNode();
} else {
current = current.getRightNode();
}
if (current == null) {
return null;
}
}
return current;
}
// 修改方法
public void change(int keyData, int newOtherData) {
Node findNode = find(keyData);
findNode.setOtherData(newOtherData);
}
// 先序遍历
public void preOrder(Node node) {
if (node != null) {
node.display();
preOrder(node.getLeftNode());
preOrder(node.getRightNode());
}
}
// 中序遍历
public void inOrder(Node node) {
if (node != null) {
inOrder(node.getLeftNode());
node.display();
inOrder(node.getRightNode());
}
}
// 后序遍历
public void endOrder(Node node) {
if (node != null) {
endOrder(node.getLeftNode());
endOrder(node.getRightNode());
node.display();
}
}
public Node getRoot() {
return root;
}
}
测试:
Tree tree = new Tree();
tree.insert(80, 80);
tree.insert(49, 49);
tree.insert(42, 42);
tree.insert(30, 30);
tree.insert(45, 45);
tree.insert(90, 90);
tree.insert(150, 150);
tree.insert(130, 130);
tree.insert(82, 82);
System.out.println("前序遍历：");
tree.preOrder(tree.getRoot());
System.out.println("中序遍历：");
tree.inOrder(tree.getRoot());
System.out.println("后序遍历：");
tree.endOrder(tree.getRoot());