ex7_11.cpp

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#include<iostream.h>
#include<stdlib.h>

template<typename T>class BinaryTree;
template<typename T>class Node{
	Node<T> *lchild,*rchild;
	T info;
public:
	Node(){lchild=NULL;rchild=NULL;}
	Node(T data,Node<T> *left=NULL,Node<T> *right=NULL){
		info=data;
		lchild=left;
		rchild=right;
	}
	friend class BinaryTree<T>;
};
template<typename T>class BinaryTree{
	Node<T> *root;                  //二叉树的根指针
	void InOrder(Node<T> *Current);                //中序遍历
	void PreOrder(Node<T> *Current);				//前序遍历
	void PostOrder(Node<T> *Current);				//后序遍历
	void Insert(const T &data,Node<T> * &b); //插入结点，参数为引用！
	void Destory(Node<T> * Current);        //删除树
public:
	BinaryTree(){root=NULL;}						//空树构造函数
	~BinaryTree(){Destory(root);}						//析构函数
	void Creat(T* data,int n);                    //建立（排序）二叉树
	void InOrder(){InOrder(root);}                //中序遍历，共有函数为接口
	void PreOrder(){PreOrder(root);}		      //前序遍历，共有函数为接口
	void PostOrder(){PostOrder(root);}			  //后序遍历，共有函数为接口
};
template<typename T> void BinaryTree<T>::Destory(Node<T> *Current){
	if(Current!=NULL){
		Destory(Current->lchild);
		Destory(Current->rchild);
		delete Current;  						//后序释放根结点
	}
}
template<typename T>void BinaryTree<T>::Insert(const T &data,Node<T> * &b){
	if(b==NULL){								//已到空树,插入
		b=new Node<T>(data);
		if(b==NULL){
			cout<<"空间不足"<<endl;
			exit(1);
		}
	}
	else if(data<b->info) Insert(data,b->lchild);			//小于,向左子树去查
	     else Insert(data,b->rchild);	//大于等于,向右子树去查
}
template<typename T>void BinaryTree<T>::Creat(T* data,int n){		//建立一棵二叉排序树
	for(int i=0;i<n;i++) Insert(data[i],root);
}
template<typename T>void BinaryTree<T>::InOrder(Node<T> *Current){
	if(Current!=NULL){							//递归终止条件
		InOrder(Current->lchild);					//中序遍历左子树
		cout<<Current->info<<'\t';					//访问根结点，注意所放位置
		InOrder(Current->rchild);					//中序遍历右子树
	}
}
template<typename T>void BinaryTree<T>::PreOrder(Node<T> *Current){
	if(Current!=NULL){
		cout<<Current->info<<'\t';						//注意前序访问语句所放位置
		PreOrder(Current->lchild);
		PreOrder(Current->rchild);
	}
}
template<typename T>void BinaryTree<T>::PostOrder(Node<T> *Current){
	if(Current!=NULL){
		PostOrder(Current->lchild);
		PostOrder(Current->rchild);
		cout<<Current->info<<'\t';  						//后序访问根结点
	}
}

void main(){
	const int n=15;
	int i,a[n]={10,5,15,8,3,18,13,12,14,16,20,1,4,6,9};
	BinaryTree<int> btree;
	btree.Creat(a,n);
	cout<<"输入数据："<<endl;
	for(i=0;i<n;i++) cout<<a[i]<<'\t';
	cout<<endl<<"中序："<<endl;
	btree.InOrder();    //中序遍历输出升序
	cout<<endl<<"前序："<<endl;
	btree.PreOrder();
	cout<<endl<<"后序："<<endl;
	btree.PostOrder();
	cout<<endl;
}