java实现二叉树的链式存储

package com.fxr.二叉树链式存储;

import java.util.Scanner;

public class Tree {

    static final int MAXLEN = 20;
    static Scanner input = new Scanner(System.in);
    CBTType InitTree()
    {
        CBTType node;
        if((node = new CBTType()) != null)
        {
            System.out.println("请输入一个根节点的数据：");
            node.data = input.next();
            node.left = null;
            node.right = null;
            if(node != null)
            {
                return node;
            }else{
                return null;
            }
        }
        return null;
    }

    //添加节点
    void AddTreeNode(CBTType treeNode)//添加节点的实现
    {
        CBTType pnode,parent;
        String data;
        int menusel;
        if((pnode = new CBTType()) != null)
        {
            System.out.println("输入二叉树节点的数据");
            pnode.data = input.next();
            pnode.left = null;
            pnode.right = null;
            System.out.println("输入该节点的父节点的数据：");
            data = input.next();
            parent = TreeFindNode(treeNode,data);//查找制定数据的节点
            if(parent == null)//如果没有找到父节点
            {
                System.out.println("没有找到父节点");
                pnode = null;
                return;
            }
            System.out.println("1.添加该节点到左子树--2.添加节点到右子树");
            do{
                //输入选择项
                menusel = input.nextInt();
                if(menusel == 1 || menusel == 2)
                {
                    if(parent == null)
                    {
                        System.out.println("不存在父节点，请先设置父节点");
                    }else{
                        switch(menusel)
                        {
                        case 1://添加到左节点
                            if(parent.left != null)
                            {
                                System.out.println("左子树节点不为空");
                            }else{
                                parent.left = pnode;
                            }
                            break;
                        case 2://添加到右节点
                            if(parent.right != null)
                            {
                                System.out.println("右子树节点不为空");
                            }else{
                                parent.right = pnode;
                            }
                            break;
                            default:
                                System.out.println("无效的参数");

                        }

                    }
                }

            }while(menusel != 1 && menusel != 2);

        }
    }

    private CBTType TreeFindNode(CBTType treeNode, String data) {
        // 查找节点的实现
        CBTType ptr;
        if(treeNode == null)
        {
            return null;

        }else{
            if(treeNode.data.equals(data))
            {
                return treeNode;
            }else{
                //分别向左右子树递归查找
                if((ptr = TreeFindNode(treeNode.left,data))!=null )
                {
                    return ptr;
                }else if((ptr = TreeFindNode(treeNode.right,data)) != null)
                {
                    return ptr;
                }else{
                    return null;
                }
            }
        }

    }

    //获取左子树
    CBTType TreeLeftNode(CBTType treeNode)//获取左子树
    {
        if(treeNode != null)
        {
            return treeNode.left;
        }else{
            return null;
        }
    }
    //获取右子树
    CBTType TreeRightNode(CBTType treeNode)//获取左子树
    {
        if(treeNode != null)
        {
            return treeNode.right;
        }else{
            return null;
        }
    }

    //判断树是不是为空
    int TreeIsEmpty(CBTType treeNode)//判断空树
    {
        if(treeNode != null)
        {
            return 0;
        }else{
            return 1;
        }
    }

    //计算二叉树的深度
    int TreeDepth(CBTType treeNode)
    {
        int deptleft,deptright;
        if(treeNode == null)
        {
            return 0;
        }else{
            deptleft = TreeDepth(treeNode.left);//左子树深度（递归调用）
            deptright =TreeDepth(treeNode.right);//右子树深度（递归调用） 

            if(deptleft > deptright)
            {
                return deptleft+1;
            }else{
                return deptright+1;
            }

        }
    }

    //清空二叉树
    void ClearTree(CBTType treeNode)
    {
        if(treeNode !=null)
        {
            ClearTree(treeNode.left);//清空左子树
            ClearTree(treeNode.right);//清空右子树
            treeNode = null;//释放当前节点所占的内存
        }
    }

    //显示节点的数据
    void TreeNodeData(CBTType p)
    {
        System.out.printf("%s",p.data);
    }

    //按层遍历
    void LevelTree(CBTType treeNode)
    {
        CBTType p;
        CBTType[]q = new CBTType[MAXLEN];//定义一个顺序栈
        int head = 0,tail = 0;
        if(treeNode != null)//如果队首的引用不为空
        {
            tail = (tail+1)%MAXLEN;//计算循环队列队尾序号
            q[tail] = treeNode;//将二叉树根引用进队列

        }

        //队列不为空进行循环
        while(head != tail)
        {
            head = (head+1)%MAXLEN;
            p = q[head];
            TreeNodeData(p);
            if(p.left != null)
            {
                tail = (tail+1)%MAXLEN;
                q[tail] = p.left;
            }

            if(p.right != null)
            {
                tail = (tail+1)%MAXLEN;
                q[tail] = p.right;
            }

        }

    }

    //先序遍历
    void DLRTree(CBTType treeNode)
    {
        if(treeNode != null)
        {
            TreeNodeData(treeNode);
            DLRTree(treeNode.left);
            DLRTree(treeNode.right);

        }
    }

    //中序遍历
        void LDRTree(CBTType treeNode)
        {
            if(treeNode != null)
            {
                DLRTree(treeNode.left);

                TreeNodeData(treeNode);

                DLRTree(treeNode.right);

            }
        }

        //后序遍历
                void LRDTree(CBTType treeNode)
                {
                    if(treeNode != null)
                    {
                        DLRTree(treeNode.left);

                        DLRTree(treeNode.right);

                        TreeNodeData(treeNode);

                    }
                }

}