数据结构_二叉树的构建与遍历

c++实现二叉树的构建与遍历

二叉树数据示例:a(b(,d),c(e(g),f))

代码:

// 二叉树.cpp: 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<iostream>
#include<fstream>
#include<stdio.h>

using namespace std;

#define MaxSize 100
char gnodeString[100];
class node					//结点类
{
public:
	node(char data, int deep, node *initf, node *initl, node *initr);
	char data;				//数据
	int deep;				//所在深度
	node *lchild;			//指向左儿子
	node *rchild;			//指向右儿子
	node *father;			//指向父结点
};

node::node(char data, int deep, node *initf, node *initl, node *initr)
{
	this->data = data;
	this->deep = deep;
	this->father = initf;
	this->lchild = initl;
	this->rchild = initr;
}							//方便后面的代码初始化node

class btree					//二叉树类
{
public:
	btree();
	~btree();
	void createbtree();					//二叉树建立
	void visit(node *searchp);
	node *getroot();
	void preorder(node * searchp);		//先跟遍历
	void inorder(node * searchp);		//中跟遍历
	void postorder(node * searchp);		//后跟遍历
	void nrpreorder(node * searchp);	//非递归先跟遍历
	void nrinorder(node * searchp);		//非递归中跟遍历
	void nrpostorder(node * searchp);	//非递归后跟遍历
private:
	node * root;
	node *workinp;						//工作指针	
	node *newnode;
};
btree::btree()
{
}
btree::~btree()
{
}
void btree::createbtree()				//二叉树的构建
{
	root = new node(gnodeString[0], 1, NULL, NULL, NULL);
	workinp = root;
	for (int i = 1; gnodeString[i] != '\0'; i++)
	{
		char choice = gnodeString[i];
		switch (choice)
		{
		case '(':
			if (gnodeString[i + 1] == ',')
			{
				i = i + 2;
				newnode = new node(gnodeString[i], workinp->deep + 1, NULL, NULL, NULL);
				workinp->rchild = newnode;			
				newnode->father = workinp;
				i++;
			}
			else
			{
				i++;
				newnode = new node(gnodeString[i], workinp->deep + 1, NULL, NULL, NULL); //新建结点
				workinp->lchild = newnode;			//建立父子关系
				newnode->father = workinp;			//建立父子关系
				workinp = workinp->lchild;			//工作指针移动
			}
			break;
		case ',':
			i++;
			workinp = workinp->father;
			newnode = new node(gnodeString[i], workinp->deep + 1, NULL, NULL, NULL);
			workinp->rchild = newnode;
			newnode->father = workinp;
			workinp = workinp->rchild;
			break;
		case ')':
			workinp = workinp->father;
			break;
		}
	}
}

node * btree::getroot()
{
	return root;
}
void btree::visit(node * searchp)
{
	cout << " " << searchp->data;
}
void btree::preorder(node * searchp)
{
	if (searchp != NULL)
	{
		visit(searchp);
		preorder(searchp->lchild);
		preorder(searchp->rchild);
	}
}
void btree::inorder(node * searchp)
{
	if (searchp!=NULL) 
	{
		inorder(searchp->lchild);
		visit(searchp);
		inorder(searchp->rchild);
	}
}
void btree::postorder(node * searchp)
{
	if (searchp != NULL)
	{
		postorder(searchp->lchild);
		postorder(searchp->rchild);
		visit(searchp);
	}
}
void btree::nrpreorder(node * searchp)
{
	node *stack[MaxSize], *pnow;			//启用栈的思想来处理
	int top = 0;
	pnow = searchp;
	while (!(pnow == NULL&&top == 0) )
	{
		while (pnow != NULL)
		{
			visit(pnow);
			stack[top] = pnow;
			top++;
			pnow = pnow->lchild;
		}									//依次移向左儿子
		if (top <= 0)
			return;
		else
		{
			top--;
			pnow = stack[top];
			pnow = pnow->rchild;
		}									//依次出栈并指向右儿子
	}
}
void btree::nrinorder(node * searchp)
{
	node *stack[MaxSize], *pnow;
	int top = 0;
	pnow = searchp;
	while (!(pnow == NULL && top == 0))
	{
		while (pnow != NULL)
		{
			stack[top] = pnow;
			top++;
			pnow = pnow->lchild;
		}
		if (top <= 0)
			return;
		else
		{
			top--;
			pnow = stack[top];
			visit(pnow);
			pnow = pnow->rchild;
		}
	}
}
void btree::nrpostorder(node * searchp)
{
	struct stackdata
	{
		node *link;
		int flag;
	};
	stackdata stack[MaxSize];
	node *pnow;
	int top = -1, sign;
	pnow = searchp;
	while (!(pnow == NULL && top == -1)) 
	{
		if (pnow != NULL) 
		{
			top++;
			stack[top].link = pnow;
			stack[top].flag = 1;
			pnow = pnow->lchild;
		}
		else
		{
			pnow = stack[top].link;
			sign = stack[top].flag;
			top--;
			if (sign == 1) 
			{
				top++;
				stack[top].link = pnow;
				stack[top].flag = 2;
				pnow = pnow->rchild;
			}
			else
			{
				visit(pnow);
				pnow = NULL;
			}
		}
	}
	return;
}
void readData()
{
	ifstream in("Data.txt");
	char ch;
	int index = 0;
	if (in)
	{
		while (!in.eof())
		{
			in >> ch;
			gnodeString[index++] = ch;
		}
		gnodeString[--index] = '\0';
	}
	else								//没有该文件  
	{
		cout << "no such file" << endl;
	}
}

int main()
{
	readData();
	cout << gnodeString;
	btree b = btree();
	b.createbtree();
	cout << endl << "递归先根遍历如下:" << endl;
	b.preorder(b.getroot());
	cout << endl << "递归中根遍历如下:" << endl;
	b.inorder(b.getroot());
	cout << endl << "递归后根遍历如下:" << endl;
	b.postorder(b.getroot());
	cout << endl << "非递归先根遍历如下:" << endl;
	b.nrpreorder(b.getroot());
	cout << endl << "非递归中根遍历如下:" << endl;
	b.nrinorder(b.getroot());
	cout << endl << "非递归后根遍历如下:" << endl;
	b.nrpostorder(b.getroot());
	cout << endl;
	system("pause");
    return 0;
}