//// Threaded Binary Tree.cpp : Defines the entry point for the console application.
/*-----CODE FOR FUN---------------
-------CREATED BY Dream_Whui------
-------2015-2-6-------------------*/

#include "stdafx.h"
#include <iostream>
#include <stack>
using namespace std;

#define   TRUE                    1
#define   FALSE                    0
#define   OK                    1
#define   ERROR                    0
#define   OVERFLOW                -2
#define   INFEASIBLE            -1

#define TelemType char

typedef enum PointerTag
{
    Link,
    Thread
};

typedef struct BiThrNode//定義線索連結串列的結構
{
    TelemType data;//結點元素值
    struct BiThrNode *lchild, *rchild;//左子樹，右子樹
    PointerTag    LTag, RTag;//LTag=0,lchild表示左孩子，LTag=1.lchild表示直接前驅；同理得RTag和rchild
}BiThrNode, *BiThrTree;

int CreateBiThrTree(BiThrTree &T)//按先序建立樹
{
    char ch;
    cin>>ch;
    if(ch=='#')
        T=NULL;
    else
    {
        T = (BiThrTree)malloc(sizeof(BiThrTree));
        T->data = ch;
        CreateBiThrTree(T->lchild);
        CreateBiThrTree(T->rchild);
    }
    return OK;
}

void InThreading(BiThrTree p, BiThrTree &pre)
{
    if(p)
    {
        InThreading(p->lchild,pre);//左子樹線索化
        if(!p->lchild)//前驅線索
        {
            p->LTag = Thread;
            p->lchild = pre;
        }
        else
            p->LTag = Link;
        if(!pre->rchild)//後繼線索
        {
            pre->RTag = Thread;
            pre->rchild = p;
        }
        pre = p;
        pre->RTag = Link;
        InThreading(p->rchild,pre);//右子樹線索化
    }
}

int InOrderThreading(BiThrTree &Thrt, BiThrTree T)//中序遍歷二叉樹，並將其中序線索化
{
    BiThrTree pre;
    Thrt = (BiThrTree)malloc(sizeof(BiThrTree));//建立頭結點
    if(!Thrt)
        return ERROR;
    Thrt->LTag = Link;
    Thrt->RTag = Thread;
    Thrt->rchild = Thrt;
    if(!T)
        Thrt->lchild = Thrt;
    else
    {
        pre = Thrt;
        Thrt->lchild = T;
        InThreading(T,pre);
        pre->RTag = Thread;//最後一個結點線索化
        pre->rchild = Thrt;
        Thrt->rchild = pre;
    }
    return OK;
}

void Visit(TelemType e)
{
    cout<<e<<" ";
}

int InOrderTraverse_Thr(BiThrTree T, void(*Visit)(TelemType))//線索化訪問
{
    BiThrTree p = T->lchild;
    while(p!=T)
    {
        while(p->LTag == Link)
            p = p->lchild;
        Visit(p->data);
        while(p->RTag == Thread && p->rchild != T)
        {
            p = p->rchild;
            Visit(p->data);
        }
        p = p->rchild;
    }
    return OK;
}

int main(int argc, char* argv[])
{
    BiThrTree f = NULL;
    CreateBiThrTree(f);
    BiThrTree P;
    InOrderThreading(P,f);
    InOrderTraverse_Thr(P,Visit);
    cout<<"................"<<endl;
    return 0;
}