原理图：
理论值：
前序遍历：10 5 3 6 20 15 30
中序遍历：3 5 6 10 15 20 30
后序遍历：3 6 5 15 30 20 10
运行结果：
源代码：
Node参见上一节，这里就不装逼了。
Tree：
public class Tree {
public Node root; //根节点
public void insert(int value,String name) //插入结点
{
//封装成结点
Node newNode = new Node(value,name);
//引用当前结点
Node current = root;
//引用父结点
Node parent;
//判断是否为空树
if(current == null)
{
root = newNode;
return;
}else
{
while(true)
{
parent = current; //父结点指向当前结点
if(current.data > value) //要插入的值小于该结点的值
{
current = current.leftChild; //往左走
if(current == null) //到了叶子结点
{
parent.leftChild =newNode;
return;
}
}
else
{
current = current.rightChild; //往右走
if(current == null)
{
parent.rightChild = newNode;
return;
}
}
}
}
}
//查找结点
public Node find(int value)
{
Node current = root; //指向根节点
while(current.data != value)
{
if(current.data > value)
{
current = current.leftChild;
}
else
{
current = current.rightChild;
}
if(current == null)
{
return null;
}
}
return current;
}
/*
* 前序遍历
* */
public void frontOrder(Node localNode)
{
if(localNode != null) //遍历的不是叶子结点
{
System.out.print(localNode.data + "," + localNode.name+" "); //打印根
frontOrder(localNode.leftChild); //左子树
frontOrder(localNode.rightChild); //右子树
}
}
/*中序遍历*/
public void inOrder(Node localNode)
{
if(localNode != null)
{
inOrder(localNode.leftChild); //中序遍历左子树
System.out.print(localNode.data + "," + localNode.name+" "); //打印根
inOrder(localNode.rightChild); //遍历右子树
}
}
/*后序遍历*/
public void lastOrder(Node localNode)
{
if(localNode != null)
{
lastOrder(localNode.leftChild); //后序遍历左子树
lastOrder(localNode.rightChild); //后序遍历右子树
System.out.print(localNode.data + "," + localNode.name+" "); //打印根
}
}
}