二叉树

来源：互联网发布：linux mv r 编辑：程序博客网时间：2024/06/07 16:13

二叉树的代码，循环遍历，先序遍历，中序遍历，按照二叉树的层来遍历；
其中比较麻烦一点的是循环中序遍历，需要用到两个栈来存储变量，有些难以理解，建议画图。回头还需要好好想想循环中序遍历的代码。

头文件代码如下，函数的申明等

#ifndef  __BINARYTREE_H_#define  __BINARYTREE_H_#include <stdio.h>#include <stdlib.h>#include <string.h>#include <stack>#include <queue>#define N 10typedef int Data;typedef struct _Node{    struct _Node *left;    struct _Node *right;    Data data;} Node;void createTree(Node **pRoot);void freeTree(Node *pRoot);void midPrintTree(Node *pRoot);void prePrintTree(Node *pRoot);void insertNode(Node **ppRoot, Data &val);void midPrintTree_loop(Node *pRoot);void prePrintTree_loop(Node *pRoot);void layerPrintTree(Node *pRoot);Data varr[N] = {10, 38, 100, -3, 80, -20, 91, 27, 50, 350};#endif  //__BINARYTREE_H_

主要的main函数代码如下：
请注意一下循环的树遍历代码

#include "binaryTree1.h"void createTree(Node **ppRoot){    Node *pRoot = *ppRoot;    //*ppRoot = NULL;    int i = 0;    Node *pNode = NULL;    Node *pNode1 = NULL;    for(i = 0; i < 10; ++ i)    {        pNode = (Node *)malloc(sizeof(Node));        pNode -> data = varr[i];        pNode -> left = NULL;        pNode -> right = NULL;        if(NULL == *ppRoot)        {            *ppRoot = pNode;            pNode1 = *ppRoot;        }        else        {            pNode1 = *ppRoot;            while(pNode1 != NULL)            {                if(pNode -> data < pNode1 -> data)                {                    if(pNode1 -> left != NULL)                    {                        pNode1 = pNode1 -> left;                        continue;                    }else{                        pNode1 -> left = pNode;                        break;                    }                }                if(pNode -> data >= pNode1 -> data)                {                    if(pNode1 -> right != NULL)                    {                        pNode1 = pNode1 -> right;                        continue;                    }else{                        pNode1 -> right = pNode;                        break;                    }                }            }        }    }}void freeTree(Node *pRoot){    if(NULL == pRoot)        return;    freeTree(pRoot -> left);    freeTree(pRoot -> right);    pRoot -> left = NULL;    pRoot -> right = NULL;    free(pRoot);    pRoot = NULL;}void midPrintTree(Node *pRoot){    if(NULL == pRoot)        return;    //printf("%d\t", pRoot -> data);    midPrintTree(pRoot -> left);    printf("%d\t", pRoot -> data);    midPrintTree(pRoot -> right);}void prePrintTree(Node *pRoot){    if(NULL == pRoot)        return;    printf("%d\t", pRoot -> data);    prePrintTree(pRoot -> left);    //printf("%d\t", pRoot -> data);    prePrintTree(pRoot -> right);}void insertNode(Node **ppRoot, Data &val){    //Node *pRoot = *ppRoot;    Node *pNode = (Node *)malloc(sizeof(Node));    //pNode = (Node *)malloc(sizeof(Node));    pNode -> data = val;    pNode -> left = NULL;    pNode -> right = NULL;    if(NULL == *ppRoot)    {        //printf("Insert function\n");        *ppRoot = pNode;        return;    }    //Node *pRoot = *ppRoot;    Node *pNode_tmp = *ppRoot;    Node *pNode_tmp1 = *ppRoot;    while(pNode_tmp != NULL)    {        if(val < pNode_tmp -> data)        {            pNode_tmp1 = pNode_tmp;            pNode_tmp = pNode_tmp -> left;            continue;        }        if(val >= pNode_tmp -> data)        {            pNode_tmp1 = pNode_tmp;            pNode_tmp = pNode_tmp -> right;            continue;        }    }    if(pNode_tmp1 -> data < val)        pNode_tmp1 -> right = pNode;    else        pNode_tmp1 -> left = pNode;    //pNode_tmp = pNode;}void midPrintTree_loop(Node *pRoot){    if(NULL == pRoot)        return ;    std::stack<Node *> pstack;    Node *pNode = NULL;    Node *pNode_mid = NULL;    pstack.push(pRoot);    pNode_mid = pRoot -> left;    while(!pstack.empty() || pNode_mid != NULL)    {        if(NULL != pNode_mid)        {            pstack.push(pNode_mid);            pNode_mid = pNode_mid -> left;            continue;        }        if(pNode != NULL)        {            printf("%d\t", pNode -> data);            pNode = NULL;        }        if(pNode_mid == NULL)        {            pNode = pstack.top();            pstack.pop();            if(NULL != pNode -> right)                pNode_mid = pNode -> right;        }    }    if(NULL != pNode)    {        printf("%d\t", pNode -> data);        pNode = NULL;    }}void prePrintTree_loop(Node *pRoot){    if(NULL == pRoot)        return ;    std::stack<Node *> pstack;    Node *pNode = NULL;    pstack.push(pRoot);    while(!pstack.empty())    {        pNode = pstack.top();        pstack.pop();        printf("%d\t", pNode -> data);        if(NULL != pNode -> right)            pstack.push(pNode -> right);        if(NULL != pNode -> left)            pstack.push(pNode -> left);    }    /*    if(pNode != NULL)    {        printf("%d\t", pNode -> data);        pNode = NULL;    }    */}void layerPrintTree(Node *pRoot){    if(NULL == pRoot)        return ;    std::queue<Node *> pqueue;    pqueue.push(pRoot);    Node *pNode = NULL;    while(!pqueue.empty())    {        pNode = pqueue.front();        printf("%d\t", pNode -> data);        pqueue.pop();        if(NULL != pNode -> left)            pqueue.push(pNode -> left);        if(NULL != pNode -> right)            pqueue.push(pNode -> right);    }}int main(){    Node *pRoot = NULL;    createTree(&pRoot);    if(pRoot == NULL)        printf("pRoot NULL\n");    midPrintTree(pRoot);    printf("\n");    midPrintTree_loop(pRoot);    printf("\n");    //////////////////////////////////////    prePrintTree(pRoot);    printf("\n");    prePrintTree_loop(pRoot);    printf("\n");    layerPrintTree(pRoot);    printf("\n");    freeTree(pRoot);    return 0;}

接下来要学习的是图的遍历创建等

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