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);

}
}

}