数据结构---线索二叉树

#define QUEUE_MAXSIZE 50

typedef char DATA; typedef enum {         SubTree,         Thread

}NodeFlag;

//线索二叉树结构 typedef struct ThreadTree {         DATA data;         NodeFlag lflag;         NodeFlag rflag;         struct ThreadTree *left;         struct ThreadTree *right; }ThreadBinTree;

ThreadBinTree *Previous = NULL;

//查找后继结点 ThreadBinTree *BinTreeNext_LDR(ThreadBinTree *bt) {         ThreadBinTree *nextnode;         if(!bt) return NULL;         if(bt->rflag == Thread)                 return bt->right;         else         {                 nextnode=bt->right;                 while(nextnode->lflag == SubTree)                 nextnode=nextnode->left;                 return nextnode;         }

}

//查找前驱结点

ThreadBinTree *BinTreePrevious_LDR(ThreadBinTree *bt) {         ThreadBinTree *prenode;         if(!bt) return NULL;         if(bt->lflag == Thread)                 return bt->left;         else         {                 prenode = bt->left;                 while(prenode->rflag == SubTree)                         prenode = prenode->left;                 return prenode;         }

}

//遍历线索二叉树 void ThreadBinTree_LDR(ThreadBinTree *bt,void(*oper)(ThreadBinTree *p)) {         if(bt)         {                 while(bt->lflag == SubTree)                 bt=bt->left;                 do                 {                         oper(bt);                         bt=BinTreeNext_LDR(bt);                 }while(bt);         } }