中序线索化二叉树

#include<stdio.h>//A R # T # # Y E # # #
#include<iostream>
using namespace std;

struct threadnode
{
    char v;
    int ltag,rtag;
    threadnode*ls,*rs;

};
// 定义pre为全局变量可以
class threadbitree
{
    private:
        threadnode*root; //指向中序化线索二叉树根节点的指针
        threadnode*pre;  //指向上一次访问的节点
    public:
        threadbitree()//构造函数
        {
            pre=NULL;
            root=creat();//建立一棵二叉树
            cout<<"/中序线索化遍历："<<endl;
            inthread(root);//把root指针指向的树中序线索化
            inorder();//把中序线索树遍历一遍，输出结果和二叉树的中序遍历结果相同
        }
        ~threadbitree()//析构函数
        {

        }
        threadnode*next(threadnode*p)//查找p的后继
        {
            struct threadnode*q;
            if(p->rtag==1)
                q=p->rs;
            else
            {
                q=p->rs;
                while(q->ltag==0)
                    q=q->ls;
            }
            return q;

        }

        void inorder()
        {
            struct threadnode*p;
            if(root==NULL) return ;
            p=root;
            while(p->ltag==0)
                p=p->ls;
            cout<<p->v<<" ";
            while(p->rs!=NULL)
            {
                p=next(p);
                cout<<p->v<<" ";
            }


        }


    private:
            threadnode*creat()
            {
                char ch;
                cin>>ch;
                if(ch=='#')
                    return NULL;
                struct threadnode*p=new threadnode;
                p->v=ch;
                p->ltag=p->rtag=0;
                p->ls=creat();
                p->rs=creat();
                return p;
            }
            void inthread(threadnode*now)
            {
                if(now==NULL) return ;
                inthread(now->ls);
                if(now->ls==NULL)
                {
                    now->ltag=1;
                    now->ls=pre;
                }
                if(now->rs==NULL)
                {
                    now->rtag=1;
                }
                if(pre!=NULL&&pre->rtag==1)
                {
                    pre->rs=now;
                }
                pre=now;
                inthread(pre->rs);

            }
};

int main()
{
    threadbitree t;
    return 0;

}