二叉树的遍历

来源：互联网发布：webstorm mac怎么用编辑：程序博客网时间：2024/05/14 02:45

我的二叉树的遍历都是用递归实现的。二叉树的创建就不再说了，如果不懂可以看这几篇文章。

二叉树的实现（2）链表

http://blog.csdn.net/liuzuyi200/article/details/24232937

二叉树的几种实现方式(1)数组法

http://blog.csdn.net/liuzuyi200/article/details/24232453

所谓的遍历是以根节点做标准的，若根节点在左中右三个结点中最先输出，叫前序遍历，

以此类推，，若根节点在左中右三个结点中第二个输出，叫中序遍历，若根节点在左中右三个结点中最后输出，叫后序遍历，

（1）前序遍历的实现过程

void perorder( btree ptr)
{
if( ptr != NULL )
{
printf("[%2d]\n",ptr->data);
perorder( ptr->left );
perorder(ptr->right);
}
}

（2）中序遍历的实现过程

void inorder( btree ptr)
{
if( ptr != NULL )
{
inorder( ptr->left );
printf("[%2d]\n",ptr->data);
inorder(ptr->right);
}
}

（3）后序遍历的实现过程

void postorder( btree ptr)
{
if( ptr != NULL )
{
postorder( ptr->left );
postorder(ptr->right);
printf("[%2d]\n",ptr->data);

}
}

实现的过程

#include<stdio.h>#include<stdlib.h>struct tree{   int data;   struct tree *left;   struct tree *right;};typedef struct tree treenode;typedef treenode *btree;btree insert_node( btree root ,int value)   {    btree newnode;    btree current;    btree back;            newnode = (btree ) malloc(sizeof(treenode));         newnode->data = value;         newnode->left = NULL;         newnode->left = NULL;            if( root == NULL )         {              return  newnode;         }      else         {                      current = root;             while(current != NULL )                       {                         back =  current;                          if( current->data > value )                                current =  current->left;                          else                                current =  current->right;                                    }              if(back->data > value)                back->left =newnode;              else                back->right =newnode;                         }         return root;   }btree creatbtree( int *data,int len ){   btree root = NULL;   int i;    for( i = 0; i < len ; i++)       {         root = insert_node( root , data[i] );       }     return root;}void postorder( btree ptr){    if( ptr != NULL )     {         postorder( ptr->left );         postorder(ptr->right);         printf("[%2d]\n",ptr->data);           }}void perorder( btree ptr){    if( ptr != NULL )     {        printf("[%2d]\n",ptr->data);       perorder( ptr->left );       perorder(ptr->right);     }}void inorder( btree ptr){    if( ptr != NULL )     {       inorder( ptr->left );         printf("[%2d]\n",ptr->data);       inorder(ptr->right);     }}int main(){   btree root = NULL;   int data[9] ={5,6,4,8,2,3,7,1,9};    root = creatbtree(data,9);    printf("树的结点内容\n");     postorder(root);      inorder(root);   perorder(root);   return 0 ; }

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