java创建树及实现遍历

树的存储结构有四种

1、双亲链表存储结构（查找指定结点的双亲结点容易，但查找指定结点的孩子结点不容易）

2、孩子链表存储结构

3、双亲孩子链表存储结构

4、孩子兄弟链表存储结构

其中孩子兄弟链表存储结构中结点类的描述

package practice4;public class cstreeNode {private Object data; //结点的数据域private cstreeNode firstchild,nextsibling;  //左孩子，右兄弟public cstreeNode(){   //构造一个空结点this(null);}public cstreeNode(Object data){   //构造一个左孩子，右兄弟为空的结点this(data,null,null);}public cstreeNode(Object data,cstreeNode firstchild,cstreeNode nextsibling){this.data=data;this.firstchild=firstchild;this.nextsibling=nextsibling;}public Object getdata(){return data;}public cstreeNode getfirstchild(){return firstchild;}public cstreeNode getnextsibling(){return nextsibling;}public void setdata(Object data){this.data=data;}public void setfirstchild(cstreeNode firstchild){this.firstchild=firstchild;}public void setnextsibling(cstreeNode nextsibling){this.nextsibling=nextsibling;}}

其中树的遍历中，层次遍历需要用到队列类，在前面文章已经实现

下面是遍历的树

package practice4;public class cstree {private cstreeNode root;  //树的根节点public cstree(){      //构造一棵空树this.root=root;}public cstree(cstreeNode root){   //构造一棵树this.root=root;}public void preroottraverse(cstreeNode t){  //树的先根遍历if(t!=null){System.out.print(t.getdata());preroottraverse(t.getfirstchild());preroottraverse(t.getnextsibling());}}public void postroottraverse(cstreeNode t){  //树的后根遍历if(t!=null){postroottraverse(t.getfirstchild());System.out.print(t.getdata());postroottraverse(t.getnextsibling());}}public void leveltraverse(cstreeNode t){   //树的层次遍历if(t!=null){Linkqueue l=new Linkqueue();l.offer(t);while(!l.isEmpty()){for(t=(cstreeNode)t.poll();t!=null;t=t.getnextsibling())System.out.print(t.getdata()+" ");if(t.getfirstchild()!=null)l.offer(t.getfirstchild());}}}public cstree createcstree(){   //创建树cstreeNode k=new cstreeNode('k',null,null);cstreeNode f=new cstreeNode('f',k,null);cstreeNode e=new cstreeNode('e',null,f);cstreeNode g=new cstreeNode('g',null,null);cstreeNode l=new cstreeNode('l',null,null);cstreeNode j=new cstreeNode('j',null,null);cstreeNode i=new cstreeNode('i',l,j);cstreeNode h=new cstreeNode('h',null,i);cstreeNode d=new cstreeNode('d',h,null);cstreeNode c=new cstreeNode('c',g,d);cstreeNode b=new cstreeNode('b',e,c);cstreeNode a=new cstreeNode('a',b,null);return new cstree(a);   //创建根节点为a的树}public static void main(String[] args){cstree debug=new cstree();  cstree cs=debug.createcstree();cstreeNode root=cs.root;  //取得树的根节点System.out.println("树的先根遍历");cs.preroottraverse(root);System.out.println();System.out.println("树的后根遍历");cs.postroottraverse(root);}}

运行结果