二叉树的两种遍历方式[递归遍历][非递归遍历]

二叉树递归遍历：

#include <stdio.h>#include <stdlib.h>#include <string.h>//二叉树结点typedef struct BINARYNODE{char ch;struct BINARYNODE* lchild;struct BINARYNODE* rchild;}BinaryNode;//递归遍历void Recursion(BinaryNode* root){if (root == NULL){return;}//再遍历左子树Recursion(root->lchild);//再遍历右子树Recursion(root->rchild);//先访问根结点printf("%c", root->ch);}void CresteBinaryTree(){ //创建结点BinaryNode node1 = { 'A', NULL, NULL };BinaryNode node2 = { 'B', NULL, NULL };BinaryNode node3 = { 'C', NULL, NULL };BinaryNode node4 = { 'D', NULL, NULL };BinaryNode node5 = { 'E', NULL, NULL };BinaryNode node6 = { 'F', NULL, NULL };BinaryNode node7 = { 'G', NULL, NULL };BinaryNode node8 = { 'H', NULL, NULL };//建立结点关系node1.lchild = &node2;node1.rchild = &node6;node2.rchild = &node3;node3.lchild = &node4;node3.rchild = &node5;node6.rchild = &node7;node7.lchild = &node8;//递归遍历Recursion(&node1);printf("\n");}int main(void){CresteBinaryTree();system("pause");return 0;}

二叉树的非递归遍历：LinkStack.h#ifndef LINKSTACK_H#define LINKSTACK_H#include <stdlib.h>#include <stdio.h>//链式栈的结点typedef struct LINKNODE{struct LINKNODE* next;}LinkNode;//链式栈typedef struct LINKSTACK{LinkNode head;int size;}LinkStack;//初始化函数LinkStack* Init_LinkStack();//入栈void Push_LinkStack(LinkStack* stack, LinkNode* data);//出栈void Pop_LinkStack(LinkStack* stack);//返回栈顶元素LinkNode* Top_LinkStack(LinkStack* stack);//返回栈元素的个数int Size_LinkStack(LinkStack* stack);//清空栈void Clear_LinkStack(LinkStack* stack);//销毁栈void FreeSpace_LinkStack(LinkStack* stack);#endifLinkStack.c#include"LinkStack.h"//初始化函数LinkStack* Init_LinkStack(){LinkStack* stack = (LinkStack*)malloc(sizeof(LinkStack));stack->head.next = NULL;stack->size = 0;return stack;}//入栈void Push_LinkStack(LinkStack* stack, LinkNode* data){if (stack == NULL){return;}if (data == NULL){return;}data->next = stack->head.next;stack->head.next = data;stack->size++;}//出栈void Pop_LinkStack(LinkStack* stack){if (stack == NULL){return;}if (stack->size == 0){return;}//第一个有效结点LinkNode* pNext = stack->head.next;stack->head.next = pNext->next;stack->size--;}//返回栈顶元素LinkNode* Top_LinkStack(LinkStack* stack){if (stack == NULL){return NULL;}if (stack->size == 0){return NULL;}return stack->head.next;}//返回栈元素的个数int Size_LinkStack(LinkStack* stack){if (stack == NULL){return -1;}return stack->size;}//清空栈void Clear_LinkStack(LinkStack* stack){if (stack == NULL){return;}stack->head.next = NULL;stack->size = 0;}//销毁栈void FreeSpace_LinkStack(LinkStack* stack){if (stack == NULL){return;}free(stack);}main.c#define _CRT_SECURE_NO_WARNINGS#include <stdio.h>#include <stdlib.h>#include <string.h>#include "LinkStack.h"#define MY_FALSE 0#define MY_TRUE 1//二叉树结点typedef struct BINARYNODE{char ch;struct BINARYNODE* lchild;struct BINARYNODE* rchild;}BinaryNode;//二叉树的非递归遍历typedef struct BITREESTACKNODE{LinkNode node;BinaryNode* root;int flag;}BiTreeStackNode;//创建栈中的结点BiTreeStackNode* CreateBiTreeStackNode(BinaryNode* node,int flag){BiTreeStackNode* newnode = (BiTreeStackNode*)malloc(sizeof(BiTreeStackNode));newnode->root = node;newnode->flag = flag;return newnode;}//非递归遍历void NonRecursion(BinaryNode* root){//创建栈LinkStack* stack = Init_LinkStack();//把根节点扔到栈里Push_LinkStack(stack, (LinkNode*)CreateBiTreeStackNode(root, MY_FALSE));while (Size_LinkStack(stack) > 0){//先弹出栈顶元素BiTreeStackNode* node = (BiTreeStackNode*)Top_LinkStack(stack);Pop_LinkStack(stack);//判断弹出的结点是否为空if (node->root == NULL){continue;}if (node->flag == MY_TRUE){printf("%c",node->root->ch);}else{//当前结点入栈node->flag = MY_TRUE;Push_LinkStack(stack, (LinkNode*)node);//当前结点右结点入栈Push_LinkStack(stack, (LinkNode*)CreateBiTreeStackNode(node->root->rchild, MY_FALSE));//当前结点的左结点入栈Push_LinkStack(stack, (LinkNode*)CreateBiTreeStackNode(node->root->lchild, MY_FALSE));}}}void Recursion(BinaryNode* root){if (root == NULL){return;}//打印左子树Recursion(root->lchild);//打印右子树Recursion(root->rchild);printf("%c", root->ch);}void CresteBinaryTree(){//创建结点BinaryNode node1 = { 'A', NULL, NULL };BinaryNode node2 = { 'B', NULL, NULL };BinaryNode node3 = { 'C', NULL, NULL };BinaryNode node4 = { 'D', NULL, NULL };BinaryNode node5 = { 'E', NULL, NULL };BinaryNode node6 = { 'F', NULL, NULL };BinaryNode node7 = { 'G', NULL, NULL };BinaryNode node8 = { 'H', NULL, NULL };//建立结点关系node1.lchild = &node2;node1.rchild = &node6;node2.rchild = &node3;node3.lchild = &node4;node3.rchild = &node5;node6.rchild = &node7;node7.lchild = &node8;//二叉树非递归打印NonRecursion(&node1); printf("\n");Recursion(&node1); printf("\n");}int main(void){CresteBinaryTree();system("pause");return 0;}