(C语言)二叉树非递归后序(数据结构十五)

1.数据类型定义

在代码中为了清楚的表示一些错误和函数运行状态，我们预先定义一些变量来表示这些状态。在head.h头文件中有如下定义：

//定义数据结构中要用到的一些变量和类型#ifndef HEAD_H#define HEAD_H#include <stdio.h>#include <malloc.h>#include <stdlib.h>#include <math.h>#define TRUE  1#define FALSE 0#define OK    1#define ERROR  0#define INFEASIBLE -1#define OVERFLOW   -2    //分配内存出错typedef int  Status;     //函数返回值类型typedef int  ElemType;   //用户定义的数据类型#endif

2.非递归过程中需要用到栈

LinkStack.h代码如下:

#ifndef LINKSTACK_H#define LINKSTACK_H#include "head.h"//可用栈类型Stack的相关定义：typedef struct SElemType {pBiNode   root; //二叉树结点的指针类型int      tag; // 0..1}SElemType,*pType;      //栈的元素类型typedef SElemType Type;typedef struct Node{Type       data;struct Node* next;}Node,*pNode;typedef struct Stack{pNode base;pNode top;int   length;}Stack,*pStack;//初始化栈Status InitStack(pStack &S){S=(pStack)malloc(sizeof(Stack));if(!S) return OVERFLOW;S->length=0;S->base=(pNode)malloc(sizeof(Node));if(!S->base) return OVERFLOW;S->top=(pNode)malloc(sizeof(Node));if(!S->top) return OVERFLOW;S->top->next=S->base;return OK;}Status freeStack(pStack &S){free(S);S=NULL;return OK;}//清空栈Status ClearStack(pStack &S){if(S==NULL) return ERROR;pNode p=S->top;while(p->next!=S->base){pNode q=p;p=p->next;free(q);q=NULL;}S->top=p;S->length=0;return OK;}//销毁栈Status DestroyStack(pStack S){if(S==NULL) return ERROR;ClearStack(S);free(S->base);S->base=NULL;free(S->top);S->top=NULL;freeStack(S);S==NULL;return OK;}//栈是否为空Status StackEmpty(pStack S){return S->length<=0;}//栈长度int StackLength(pStack S){return S->length;}//得到栈顶数据级eStatus GetTop(pStack S,Type *e){*e=S->top->next->data;return OK;}//入栈Status Push(pStack &S,Type* e){if(S->length==0){S->base->data=*e;}else{pNode p=S->top;p->data=*e;pNode q=(pNode)malloc(sizeof(Node));q->next=p;S->top=q;}S->length++;return OK;}//出栈Status Pop(pStack S,Type *e){if (S->length<=0) return ERROR;if(S->length==1){*e=S->base->data;S->length--;}else{pNode p=S->top;S->top=p->next;*e=S->top->data;free(p);S->length--;}return OK;}Status print(Type e){printf("%d\n",e);return OK;}//用vistit遍历栈Status StackTraverse(pStack S,Status(*visit)(Type)){pNode p=S->top;do {p=p->next;(*visit)(p->data);} while (p!=S->base);return OK;}Status printStack(pStack S){if (S==NULL ||S->length==0) return ERROR;StackTraverse(S,print);return OK;}#endif

3.二叉树头文件 

BiTree.h代码如下:

#ifndef BITREE_H#define BITREE_H#include "head.h"typedef struct BiNode{ElemType data;struct BiNode *left,*right;}BiNode,*pBiNode;Status InsertRight(pBiNode &root,ElemType e);Status InsertLeft(pBiNode &root,ElemType e);Status InitBiTree(pBiNode &tree){tree=(pBiNode)malloc(sizeof(BiNode));if(!tree) return OVERFLOW;tree->data=-999999;tree->left=NULL;tree->right=NULL;return OK;}Status BiTreeEmpty(pBiNode root){if(root==NULL) return ERROR;return root->left==root->right && root->data==-999999;}Status HasNoNode(pBiNode root){if(root==NULL) return ERROR;return root->left==root->right ;}Status CreatTreeNode(pBiNode &node,ElemType e){node=(pBiNode)malloc(sizeof(BiNode));if(!node) return OVERFLOW;node->data=e;node->left=NULL;node->right=NULL;return OK;}Status InsertRight(pBiNode &root,ElemType e){if(root->right==NULL){if(e>root->data){pBiNode p;CreatTreeNode(p,e);root->right=p;return OK;}else{pBiNode p;CreatTreeNode(p,e);root->left=p;return OK;}}else{e>root->data? InsertRight(root->right,e):InsertLeft(root,e);}}Status InsertLeft(pBiNode &root,ElemType e){if(root->left==NULL){if(e>root->data){pBiNode p;CreatTreeNode(p,e);root->right=p;return OK;}else{pBiNode p;CreatTreeNode(p,e);root->left=p;return OK;}}else{e<=root->data?InsertLeft(root->left,e):InsertRight(root,e);}}Status InsertTree(pBiNode &root,ElemType e){if(BiTreeEmpty(root)){root->data=e;return true;}if(e>root->data){InsertRight(root,e);}else{InsertLeft(root,e);}}Status CreateBiTree(pBiNode &root,ElemType *a,int n){for (int i=0;i<n;i++){InsertTree(root,a[i]);}return true;} Status print(ElemType e ){ printf("%d ",e); return true; }Status PreOrderTraverse(pBiNode root,Status(*p)(int)){if(root){(*p)(root->data);PreOrderTraverse(root->left,p);PreOrderTraverse(root->right,p);}return OK;}Status MiddleOrderTraverse(pBiNode root,Status(*p)(int)){if(root){MiddleOrderTraverse(root->left,p);(*p)(root->data);MiddleOrderTraverse(root->right,p);}return OK;}Status AfterOrderTraverse(pBiNode root,Status(*p)(int)){if(root){AfterOrderTraverse(root->left,p);AfterOrderTraverse(root->right,p);(*p)(root->data);}return OK;}Status ClearBiTree(pBiNode &root){if(root){ClearBiTree(root->left);ClearBiTree(root->right);free(root);root==NULL;}return OK;}#endif

4.测试代码

#include "BiTree.h"#include "LinkStack.h"//非北递归后序void PostOrder(pBiNode root){pStack s;InitStack(s);pType p,t;p=(pType)malloc(sizeof(SElemType));t=(pType)malloc(sizeof(SElemType));p->root=root;        while(p->root ||!StackEmpty(s)){                while(p->root){p->tag= 0;Push(s,p);//printf("%d ",p->root->data);p->root=p->root->left;            }GetTop(s,t);while(t->tag && !StackEmpty(s)){Pop(s,p);printf("%d ",p->root->data);GetTop(s,t);}if(!StackEmpty(s)){GetTop(s,t);t->tag=1;Pop(s,p);Push(s,t);GetTop(s,p);p->root=p->root->right;}else{break;}}           }void main(){ElemType a[14]={100,50,200,40,30,45,60,55,61,200,150,300,250,400};pBiNode root;InitBiTree(root);CreateBiTree(root,a,14);printf("前序：");PreOrderTraverse(root,print);printf("\n中序：");MiddleOrderTraverse(root,print);printf("\n后序：");AfterOrderTraverse(root,print);printf("\n非递归后序：");PostOrder(root);printf("\n");ClearBiTree(root);}

插入的二叉树为:

5.运行结果: