数据结构——二叉树的结点插入与遍历

BTree.h:

#ifndef _BTREE_H_
#define _BTREE_H_
//二叉树的结点数据类型
typedef struct _btreeNode
{
   int data;
   struct _btreeNode *lchild;           //???
   struct _btreeNode *rchild;           //指向右孩子结点的指针
}BTreeNode;

//创建二叉树的根结点，即可创建一个二叉树
typedef struct _btree
{
BTreeNode *root; //指向根结点的指针，代表二叉树
int count; //统计二叉树结点的个数
}BTree;

//创建二叉树，实际就是创建一个 BTree 结点
BTree *creatBTree();

//插入结点
//参数
//b ：二叉树
//data ：数据
//pos ：路径 0 代表左 1 代表右路径从右往左看6:100 代表路径左左右
//count ：步数
//flag ：挂在结点的左边还是右边 0 代表左 1代表右
int BTree_insert(BTree *b,char data,int pos,int count,int flag);

//前序遍历
void pre_order(BTreeNode *root);
//中序遍历
void mid_order(BTreeNode *root);
//后序遍历
void last_order(BTreeNode *root);

#endif

BTree.c

#include<stdlib.h>
#include"BTree.h"
#include<assert.h>

BTree *creatBTree()
{
   //创建二叉树
   BTree *btree=(BTree *)malloc(sizeof(BTree)/sizeof(char));
   assert(btree);

   //对二叉树进行初始化
   btree->root=NULL;
   btree->count=0;

   return btree;
}

//插入新节点
int BTree_insert(BTree *b,char data,int pos,int count,int flag)
{
   assert(b);
   //创建新结点
   BTreeNode *node=(BTreeNode *)malloc(sizeof(BTreeNode)/sizeof(char));
   assert(node);

   //结点初始化
   node->data=data;
   node->lchild=NULL;
   node->rchild=NULL;

   int way;//当前要走的路
   BTreeNode *current=b->root;
   //找插入位置的父结点     pos：2       count=3
   while(count!=0)
   {
       way=pos&1;
       pos=pos>>1;

       if(way==0)   //往左走
           current=current->lchild;
       else           //往右走
           current=current->rchild;
       count--;
   }

   if(current==NULL)   //刚开始插入时
       b->root=node;   //新结点成为了新建二叉树的根结点
   else
   {
       if(flag==0)
       {
           node->lchild=current->lchild;
           current->lchild=node;
       }
       else
       {
           node->rchild=current->rchild;
           current->rchild=node;
       }
   }
   b->count++;       //结点个数加1
   return 0;
}

//前序   根左右
void pre_order(BTreeNode *root)
{
   if(root==NULL)
       return;
   printf("%-4c",root->data);
   pre_order(root->lchild);
   pre_order(root->rchild);
}

//中序   左根右
void mid_order(BTreeNode *root)
{
   if(root==NULL)
       return;
   mid_order(root->lchild);
   printf("%-4c",root->data);
   mid_order(root->rchild);
}

//后序   左右根
void last_order(BTreeNode *root)
{
   if(root==NULL)
       return;
   last_order(root->lchild);
   last_order(root->rchild);
   printf("%-4c",root->data);
}

main.c

#include<stdio.h>
#include"BTree.h"

int main()
{
   BTree *btree=creatBTree();

   int BTree_insert(btree,'A',0,0,0);
   int BTree_insert(btree,'B',0,0,0);
   int BTree_insert(btree,'C',1,0,1);
   int BTree_insert(btree,'D',0,1,0);
   int BTree_insert(btree,'E',0,1,1);
   int BTree_insert(btree,'F',1,1,0);
   int BTree_insert(btree,'G',1,1,1);
   int BTree_insert(btree,'H',1,2,1);

   pre_order(btree->root);
   printf("\n");
   mid_order(btree->root);
   printf("\n");
   last_order(btree->root);
   printf("\n");

return 0;

}

数据结构——二叉树的结点插入与遍历

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