二叉树（前序遍历+中序遍历+后序遍历）递归

// BinaryTree.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include<iostream>
#include <algorithm>
#include<queue>
using namespace std;
template <class T>
struct BiNode   //二叉树的结点结构
{
    T data;
    BiNode<T> *lchild, *rchild;

};
template <class T>
class BiTree
{
public:
    BiTree();             //构造函数，初始化一棵二叉树，其前序序列由键盘输入
    ~BiTree(void);         //析构函数，释放二叉链表中各结点的存储空间
    BiNode<T>* Getroot();  //获得指向根结点的指针
    void PreOrder(BiNode<T> *root);     //前序遍历二叉树
    void InOrder(BiNode<T> *root);      //中序遍历二叉树
    void PostOrder(BiNode<T> *root);    //后序遍历二叉树
    void LeverOrder(BiNode<T> *root);   //层序遍历二叉树
    int Leaf (BiNode<T> *root);    //计算二叉树的叶子数
    int Deep(BiNode<T> *root);     //计算二叉树的树高
    bool isComplete(BiNode<T> *root);//判断是否为完全二叉树
private:
    BiNode<T> *root;         //指向根结点的头指针
    BiNode<T> *Creat();     //有参构造函数调用
    void Release(BiNode<T> *root);   //析构函数调用 
};
template<class T>
BiTree<T>::BiTree()
{
    this->root = Creat();
}
template <class T>
BiNode<T>* BiTree<T>::Creat()
{
    BiNode<T>* root;
    T ch;

    cout << "请输入创建一棵二叉树的结点数据" << endl;
    cin >> ch;
    if (ch == '#') root = NULL;
    else
    {
        root = new BiNode<T>;       //生成一个结点
        root->data = ch;
        root->lchild = Creat();    //递归建立左子树
        root->rchild = Creat();    //递归建立右子树
    }
    return root;
}
template<class T>
BiTree<T>::~BiTree(void)
{
    Release(root);
}
template<class T>
void BiTree<T>::Release(BiNode<T>* root)
{
    if (root != NULL) {
        Release(root->lchild);   //释放左子树
        Release(root->rchild);   //释放右子树
        delete root;
    }
}
template<class T>
BiNode<T>* BiTree<T>::Getroot()
{
    return root;
}
template<class T>
void BiTree<T>::PreOrder(BiNode<T> *root)
{
    if (root == NULL)  return;
    else {
        cout << root->data << " ";
        PreOrder(root->lchild);
        PreOrder(root->rchild);
    }
}
template <class T>
void BiTree<T>::InOrder(BiNode<T> *root)
{
    if (root == NULL)  return;      //递归调用的结束条件           
    else {
        InOrder(root->lchild);    //中序递归遍历root的左子树
        cout << root->data << " ";    //访问根结点的数据域
        InOrder(root->rchild);    //中序递归遍历root的右子树
    }
}
template <class T>
void BiTree<T>::PostOrder(BiNode<T> *root)
{
    if (root == NULL)   return;       //递归调用的结束条件
    else {
        PostOrder(root->lchild);    //后序递归遍历root的左子树
        PostOrder(root->rchild);    //后序递归遍历root的右子树
        cout << root->data << " ";      //访问根结点的数据域
    }
}

template <class T>
void BiTree<T>::LeverOrder(BiNode<T> *root)
{
    const int MaxSize = 100;
    int front = 0;
    int rear = 0;  //采用顺序队列，并假定不会发生上溢
    BiNode<T>* Q[MaxSize];
    BiNode<T>* q;
    if (root == NULL) return;
    else {
        Q[rear++] = root;
        while (front != rear)
        {
            q = Q[front++];
            cout << q->data << " ";
            if (q->lchild != NULL)    Q[rear++] = q->lchild;
            if (q->rchild != NULL)    Q[rear++] = q->rchild;
        }
    }
}
template<class T>
int BiTree<T>::Leaf(BiNode<T>* root)
{
    if (root == NULL)
        return 0;
    else if ((root->lchild == NULL) && (root->rchild == NULL))
        return 1;
    else
        return(Leaf(root->lchild) + Leaf(root->rchild));
}
template<class T>
int BiTree<T>::Deep(BiNode<T>* root)
{
    if (root == NULL)
        return 0;
    else
        return max(Deep(root->lchild), Deep(root->rchild)) + 1;
}
void main()
{
    BiTree<char> bt; //创建一棵树
    BiNode<char>* root = bt.Getroot();  //获取指向根结点的指针 
    cout << "------前序遍历------ " << endl;
    bt.PreOrder(root);
    cout << endl;
    cout << "------中序遍历------ " << endl;
    bt.InOrder(root);
    cout << endl;
    cout << "------后序遍历------ " << endl;
    bt.PostOrder(root);
    cout << endl;
    cout << "------层序遍历------ " << endl;
    bt.LeverOrder(root);
    cout << endl;
    cout << "------叶子结点------ " << endl;
    cout << bt.Leaf(root) << endl;
    cout << "------数的高度------ " << endl;
    cout << bt.Deep(root) << endl;
    system("pause");
    cout << endl;
}