数据结构中序线索二叉树C语言

#include 
using namespace std;
#define Elemtype char

typedef struct BiTNode {
    Elemtype data;
    struct BiTNode *lchild, *rchild;
    int LTag, RTag;
} BiThreadNode, *BiThreadTree;

BiThreadNode *pre; // 当前访问节点的前驱

void visit(Elemtype x) {
    cout << x << " ";
}

BiThreadTree createBiThreadTree() {
    BiThreadNode *T;
    char ch;
    if ((ch = getchar()) == '#')
        T = NULL;
    else {
        T = (BiThreadNode *)malloc(sizeof(BiThreadNode));
        T->data = ch;
        T->lchild = createBiThreadTree();
        T->rchild = createBiThreadTree();
    }
    return T;
}

void InThreading(BiThreadTree T) {
    if (T != NULL) {
        InThreading(T->lchild);
        if (T->lchild == NULL) {
            T->LTag = 1;
            T->lchild = pre;
        }
        else
            T->LTag = 0;
        if (pre->rchild == NULL) {
            pre->RTag = 1;
            pre->rchild = T;
        }
        else
            pre->RTag = 0;
        pre = T;
        InThreading(T->rchild); 
    }
}

BiThreadNode *CreateInThrTree(BiThreadTree T) {
    BiThreadNode *ThrHead; 
    ThrHead = (BiThreadNode *)malloc(sizeof(BiThreadNode));
    ThrHead->RTag = 1;
    ThrHead->rchild = ThrHead; 
    ThrHead->LTag = 0;
    if (T == NULL)
        ThrHead->lchild = ThrHead; 
    else {
        ThrHead->lchild = T;
        pre = ThrHead; 
        InThreading(T);        
        pre->rchild = ThrHead; 
        pre->RTag = 1;
        ThrHead->rchild = pre; 
    }
    return ThrHead;
}

void ThrInOrderTraverse(BiThreadTree ThrHead) {
    BiThreadNode *temp = ThrHead->lchild; 
    while (temp != ThrHead) {
        while (temp->LTag == 0)
            temp = temp->lchild; 
        visit(temp->data);
        while (temp->RTag == 1 && temp->rchild != ThrHead) {
            temp = temp->rchild;
            visit(temp->data);
        }
        temp = temp->rchild; 
    }
}

int main(void) {
    BiThreadTree root;
    root = createBiThreadTree();
    BiThreadNode *ThrHead = CreateInThrTree(root);
    ThrInOrderTraverse(ThrHead);
    return 0;
}