二叉树的查找(前序、中序、后序、层序遍历)--biaobiao88

建立一棵含有n个结点的二叉树，采用二叉链表存储；

输出前序、中序、后序、、层序遍历该二叉树的遍历结果。

定义二叉树的数据类型——二叉树结点结构体BiNode。建立二叉链表可以采用扩展二叉树的一个遍历序列，例如前序序列，将扩展二叉树的前序序列由键盘输入，建立该二叉树的二叉链表存储。

简单起见，本实验假定二叉树的数据元素为char型

用模板类改写

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<malloc.h>
int MaxSize = 100;
using namespace std;
typedef char DataType;
typedef struct BiNode
{
    DataType data;
    struct BiNode *lchile,*rchild;
}BiNode;
BiNode *root;

//创建拓展二叉树，#代虚结点 
BiNode *Creat(BiNode *root)//          cishu   /////
{
    char ch;
    cin >> ch;
    if(ch == '#')
        root = NULL;
    else
    {
        root = (BiNode *)malloc(sizeof(BiNode));
        root->data = ch;
        root->lchile = Creat(root->lchile);
        root->rchild = Creat(root->rchild);
    }
    return root;
}

//前序遍历 
void PreOrder(BiNode *root)
{
    if(root == NULL)
        return;
    else
    {
        cout << root->data << " ";
        PreOrder(root->lchile);
        PreOrder(root->rchild);
    }
}

//中序遍历 
void InOrder(BiNode *root)
{
    if(root == NULL)
        return;
    else
    {
        InOrder(root->lchile);
        cout << root->data << " ";
        InOrder(root->rchild);
    }
}

//后序遍历 
void PostOrder(BiNode *root)
{
    if(root == NULL)
        return;
    else
    {
        InOrder(root->lchile);
        InOrder(root->rchild);
        cout << root->data << " ";
    }
}

//层序遍历 
void LevelOrder(BiNode *root)
{
    BiNode *q = NULL,*Q[MaxSize];
    int front = -1;
    int rear = -1;
    if(root == NULL)
        return;
    Q[++rear] = root;
    while(front != rear)
    {
        q = Q[++front];
        cout << q->data << " ";
        if(q->lchile != NULL)
            Q[++rear] = q->lchile;
        if(q->rchild != NULL)
            Q[++rear] = q->rchild;
    }
    
}

int main()
{
    BiNode *root = NULL;
    root = Creat(root);
    cout << "该二叉树的根节点是：" << root->data << endl;
    cout << endl;
    cout << "该二叉树的前序遍历是：";
    PreOrder(root);
    cout << endl;
//    cout << "该二叉树的根节点是：" << root->data << endl;
    cout << endl;
    cout << "该二叉树的中序遍历是：";
    InOrder(root);
    cout << endl;
//    cout << "该二叉树的根节点是：" << root->data << endl;
    cout << endl;
    cout << "该二叉树的后序遍历是：";
    PostOrder(root);
    cout << endl;
//    cout << "该二叉树的根节点是：" << root->data << endl;
    cout << endl;
    cout << "该二叉树的层序遍历是：";
    LevelOrder(root);
    cout << endl;
    return 0;
}

/*
abd##e##c#f##
该二叉树的根节点是：a

该二叉树的前序遍历是：a b d e c f

该二叉树的中序遍历是：d b e a c f

该二叉树的后序遍历是：d b e c f a

该二叉树的层序遍历是：a b c d e f
*/