本文实例讲述了Java实现二叉树的建立、计算高度与递归输出操作。分享给大家供大家参考，具体如下：
1. 建立 递归输出 计算高度 前中后三种非递归输出
public class Tree_Link {
private int save = 0;
private int now = 0;
Scanner sc = new Scanner(System.in);
/*
* 构造函数
*/
Tree_Link(){
}
/*
* 链表建立
*/
public Tree Link_Build(Tree head){
// Tree head = new Tree();//头节点
System.out.println("继续code：1");
int flag = sc.nextInt();
if(flag != 1){
return head;
}else{
System.out.println("\n\n\n输入 节点信息：");
head.SetCode(sc.nextInt());
System.out.println("\n建立 左 子树code：1 否则：0");
flag = sc.nextInt();
if(flag == 1){
now++;
Tree LTree = new Tree();
head.SetLtree(LTree);
LTree.SetFronttree(head);//设置父母节点
Link_Build( head.GetLtree() );
}
System.out.println("\n当前位置：" + head.GetCode());
System.out.println("\n建立 右 子树code：1 否则：0");
flag = sc.nextInt();
if(flag == 1){
now++;
Tree Rtree = new Tree();
head.SetRtree(Rtree);
Rtree.SetFronttree(head);//设置父母节点
Link_Build( head.GetRtree() );
}
if( now > save ){
save = now;
}
now--;
}
return head;
}
/*
* 输出树
*/
public Tree output(Tree head){
int flag;
if(head.GetCode() == -1){
return head;
}else{
System.out.println("\n当前位置：" + head.GetCode());
System.out.println(head.GetLtree() != null);
if(head.GetLtree() != null){
System.out.println("\n访问 左子树:");
output( head.GetLtree() );
}
if(head.GetRtree() != null){
System.out.println("\n访问 右子树:");
output( head.GetRtree() );
}
}
return head;
}
/*
* 获得高度
*/
public int GetSave(){
return this.save;
}
/*
* 非递归 前序遍历
*/
public void Front_Traverse(Tree head){
Tree star = head;//退出标记
int choose = 1; //左
int flag = 1; //右
System.out.println( "<---前序遍历--->" + head.GetCode() );//先访问根
while(true){
if( head.GetLtree() != null && choose != 0 ){
head = head.GetLtree();
System.out.println( "<---前序遍历--->" + head.GetCode() );//获得信息
flag = 1;
}else if( head.GetRtree() != null && flag != 0 ){
head = head.GetRtree();
System.out.println( "<---前序遍历--->" + head.GetCode() );
choose = 1;
}else if( flag == 0 && choose == 0 && head == star){
break;
}else{
if(head == head.GetFronttree().GetRtree()){
flag = 0;
choose = 0;
}
if(head == head.GetFronttree().GetLtree()){
choose = 0;
flag = 1;
}
head = head.GetFronttree();
System.out.println("获得 父母" + head.GetCode());
System.out.println( "\n\n\n" );
}
}
}
/*
* 非递归 中序遍历
*/
public void Center_Traverse(Tree head){
Tree star = head;//退出标记
int choose = 1; //左
int flag = 1; //右
while(true){
if( head.GetLtree() != null && choose != 0 ){
head = head.GetLtree();
flag = 1;
}else if( head.GetRtree() != null && flag != 0 ){
if(head.GetLtree() == null){//因为左边为空而返回
System.out.println( "<-1--中序遍历--->" + head.GetCode());
}
head = head.GetRtree();
choose = 1;
}else if( flag == 0 && choose == 0 && head == star){
break;
}else{
int area = 0;//判断哪边回来
flag = 1;
choose = 1;
if(head == head.GetFronttree().GetRtree()){
area = 1;//右边回来
flag = 0;
choose = 0;
}
if(head == head.GetFronttree().GetLtree()){
area = 2;//左边回来
choose = 0;
flag = 1;
}
if( head.GetLtree() == null && head.GetRtree() == null ){//因为左边为空而返回
System.out.println( "<-2--中序遍历--->" + head.GetCode());
}
head = head.GetFronttree();
if( area == 2){//因为左边访问完返回
System.out.println( "<-3--中序遍历--->" + head.GetCode());
}
System.out.println("获得 父母" + head.GetCode());
System.out.println( "\n\n\n" );
}
}
}
/*
* 非递归 后续遍历
*/
public void Bottom_Traverse(Tree head){
Tree star = head;//退出标记
int choose = 1; //左
int flag = 1; //右
while(true){
if( head.GetLtree() != null && choose != 0 ){
head = head.GetLtree();
flag = 1;
}else if( head.GetRtree() != null && flag != 0 ){
head = head.GetRtree();
choose = 1;
}else if( flag == 0 && choose == 0 && head == star){
break;
}else{
int area = 0;//判断哪边回来
flag = 1;
choose = 1;
if(head == head.GetFronttree().GetRtree()){
area = 1;//右边回来
flag = 0;
choose = 0;
}
if(head == head.GetFronttree().GetLtree()){
choose = 0;
flag = 1;
}
if(head.GetRtree() == null){//因为右边为空而返回
System.out.println( "<-1--后序遍历--->" + head.GetCode());
}
head = head.GetFronttree();
if( area == 1){
System.out.println( "<-2--后序遍历--->" + head.GetCode());
}
System.out.println("获得 父母" + head.GetCode());
System.out.println( "\n\n\n" );
}
}
}
}
2. Tree 类实现：
public class Tree {
private int code = -1;
private Tree Fonttree;
private Tree Ltree;
private Tree Rtree;
Tree(){
this.code = -1;
this.Ltree = null;
this.Rtree = null;
}
/*
* 树内容查看方法：
*/
public void SetCode(int code){//设置编号
this.code = code;
}
public int GetCode(){ //获取编号
return this.code;
}
/*
* 设置父母指针：
*/
public void SetFronttree(Tree Front){
this.Fonttree = Front;
}
public Tree GetFronttree(){
System.out.println("获得 父母");
return this.Fonttree;
}
/*
* 设置左子女：
*/
public void SetLtree(Tree Ltree){
this.Ltree = Ltree;
}
public Tree GetLtree(){
System.out.println("获得左子树");
return this.Ltree;
}
/*
* 设置右子女：
*/
public void SetRtree(Tree Rtree){
this.Rtree = Rtree;
}
public Tree GetRtree(){
System.out.println("获得右子树");
return this.Rtree;
}
}
3. 主函数测试：
public class MainActivity {
Scanner sc = new Scanner(System.in);
public static void main(String[] args) {
Tree head = new Tree();
Tree_Link link_1st = new Tree_Link();
head = link_1st.Link_Build(head);
System.out.println("Build succeed !");
System.out.println("\n二叉树高度-->" + link_1st.GetSave());
link_1st.output(head);
System.out.println("Output Over !");
System.out.println("\n\n<----------------前------------------>\n前序访问根：");
link_1st.Front_Traverse(head);
System.out.println("\n\n<----------------中------------------>\n中序访问根：");
link_1st.Center_Traverse(head);
System.out.println("\n\n<----------------后------------------>\n后序访问根：");
link_1st.Bottom_Traverse(head);
System.out.println("\n\n\n\nText over !\n\n\n");
}
}
希望本文所述对大家java程序设计有所帮助。
