数据结构与算法编程题24

中序遍历非递归算法

#define _CRT_SECURE_NO_WARNINGS#include <iostream>
using namespace std;typedef char ElemType;
#define ERROR 0
#define OK 1
#define Maxsize 100
#define STR_SIZE 1024typedef struct BiTNode
{ElemType data;BiTNode* lchild, * rchild;
}BiTNode, * BiTree;void draw(BiTNode* root);//-------------------------堆栈操作---------------------------//
typedef struct SqStack
{BiTNode* data[Maxsize];int top;
}SqStack;void Init_Stack(SqStack& S)
{S.top = -1;
}bool Stack_Empty(SqStack S)
{if (S.top == -1){cout << "堆栈为空!!!" << endl;return OK;}return ERROR;
}bool Push(SqStack& S, BiTNode* x)
{if (S.top == Maxsize - 1){cout << "堆栈已经满，无法继续推入数据!!!" << endl;return ERROR;}S.data[++S.top] = x;return OK;
}bool Pop(SqStack& S, BiTNode* &x)
{if (S.top == -1){cout << "堆栈为空，无法继续推出数据!!!" << endl;return ERROR;}x = S.data[S.top--];cout << "推出元素为: " << x << endl;return OK;
}
//-------------------------堆栈操作---------------------------//
bool Create_tree(BiTree& T) //递归创建二叉树
{ElemType x = 0;cin >> x;if (x == '#'){T = NULL;}else{T = (BiTree)malloc(sizeof(BiTNode));if (T == NULL){cout << "内存无法分配!!!" << endl;return ERROR;}T->data = x;T->lchild = NULL;T->rchild = NULL;Create_tree(T->lchild);Create_tree(T->rchild);}return OK;
}void PreOrder(BiTree T)   //前序遍历非递归
{if (T != NULL){cout << T->data;PreOrder(T->lchild);PreOrder(T->rchild);}
}void InOrder(BiTree T)    //中序遍历非递归
{if (T != NULL){InOrder(T->lchild);cout << T->data;InOrder(T->rchild);}
}void PostOrder(BiTree T)  //后序遍历非递归
{if (T != NULL){PostOrder(T->lchild);PostOrder(T->rchild);cout << T->data;}
}
//---------------------------------核心代码---------------------------------//
void InOrder_2(BiTree T)
{BiTNode* p = T;SqStack S;Init_Stack(S);while (p != NULL|| Stack_Empty(S)!=OK){if (p != NULL){Push(S, p);p = p->lchild;}else{Pop(S, p);cout << p->data<<endl;p = p->rchild;}}
}
//---------------------------------核心代码---------------------------------//
//中序遍历非递归算法
//AB#D##C##
int main(void)
{cout << "//------生成一颗树---------//" << endl;BiTree T = NULL;Create_tree(T);PreOrder(T);cout << endl;InOrder(T);cout << endl;PostOrder(T);cout << endl;cout << "//------生成一颗树---------//" << endl;cout << "//------原始树图形---------//" << endl;draw(T);InOrder_2(T);return 0;
}//参考博客:https://blog.csdn.net/weixin_42109012/article/details/92250160
/*****************************************************************************
* @date   2020/4/19
* @brief  水平画树
* @param  node	二叉树节点
* @param  left	判断左右
* @param  str 	可变字符串
*****************************************************************************/
void draw_level(BiTNode* node, bool left, char* str) {if (node->rchild) {draw_level(node->rchild, false, strcat(str, (left ? "|     " : "      ")));}printf("%s", str);printf("%c", (left ? '\\' : '/'));printf("-----");printf("%c\n", node->data);if (node->lchild) {draw_level(node->lchild, true, strcat(str, (left ? "      " : "|     ")));}//  "      " : "|     " 长度为 6str[strlen(str) - 6] = '\0';
}/*****************************************************************************
* @date   2020/4/19
* @brief  根节点画树
* @param  root	二叉树根节点
*****************************************************************************/
void draw(BiTNode* root) {char str[STR_SIZE];memset(str, '\0', STR_SIZE);/*** 1. 在 windows 下，下面是可执行的* 2. 在 Linux   下，执行会报 Segmentation fault*      需要使用中间变量*/if (root->rchild) {draw_level(root->rchild, false, str);}printf("%c\n", root->data);if (root->lchild) {draw_level(root->lchild, true, str);}
}