一个简单二叉树的C++实现（一）

很久没有接触二叉树了，写这个当作练手，接下来会比较详细地实现二叉树的各个功能及应用。

/*
*   BinaryTree.cpp
*   Author: Qiang Xiao
*   Time:   2015-07-17
*/

#include<iostream>
#include<string>
using namespace std;

template<class ElemType>
class BinaryNode{
public:
    ElemType data;
    BinaryNode<ElemType>* leftChild;
    BinaryNode<ElemType>* rightChild;

    BinaryNode();
    BinaryNode(const ElemType elem, BinaryNode<ElemType>* left = NULL, BinaryNode<ElemType>* right = NULL);
    void print() const;
};

template<class ElemType>
void BinaryNode<ElemType>::print() const{
    cout << this->data << endl;
}

template<class ElemType>
BinaryNode<ElemType>::BinaryNode(){
    this->leftChild = NULL;
    this->rightChild = NULL;
}

template<class ElemType>
BinaryNode<ElemType>::BinaryNode(const ElemType elem, BinaryNode<ElemType>* left, BinaryNode<ElemType>* right){
    this->data = elem;
    this->leftChild = left;
    this->rightChild = right;
}

/**************************************************************************************************/
template<class ElemType>
class BinaryTree{
    private:
    BinaryNode<ElemType>* root;
    public:
    BinaryTree();
    BinaryTree(BinaryNode<ElemType>* r);
//    ~BinaryTree();
    BinaryNode<ElemType>* getRoot() const;
    bool isEmpty() const;
    void preOrder(BinaryNode<ElemType>* r) const;
    void inOrder(BinaryNode<ElemType>* r) const;
    void postOrder(BinaryNode<ElemType>* r) const;
};

template<class ElemType>
BinaryTree<ElemType>::BinaryTree(BinaryNode<ElemType>* r){
    root= r;
}

template<class ElemType>
BinaryTree<ElemType>::BinaryTree(){
    root= new BinaryNode<ElemType>();
}

template<class ElemType>
BinaryNode<ElemType>* BinaryTree<ElemType>::getRoot() const{
    return root;
}

template<class ElemType>
bool BinaryTree<ElemType>::isEmpty() const{
    return root== false;
}

template<class ElemType>
void BinaryTree<ElemType>::preOrder(BinaryNode<ElemType>* r) const{
    if(r== NULL)
    return;
    cout<<r->data<<"\t";
    preOrder(r->leftChild);
    preOrder(r->rightChild);
}

template<class ElemType>
void BinaryTree<ElemType>::inOrder(BinaryNode<ElemType>* r) const{
    if(r== NULL)
    return;
    inOrder(r->leftChild);
    cout<<r->data<<"\t";
    inOrder(r->rightChild);
}

template<class ElemType>
void BinaryTree<ElemType>::postOrder(BinaryNode<ElemType>* r) const{
    if(r== NULL)
    return;
    postOrder(r->leftChild);
    postOrder(r->rightChild);
    cout<<r->data<<"\t";
}

int main(){
    BinaryNode<string>* right1= new BinaryNode<string>("RIGHT1");
    BinaryNode<string>* left= new BinaryNode<string>("LEFT", NULL, right1);
    BinaryNode<string>* right= new BinaryNode<string>("RIGHT");
    BinaryNode<string>* root = new BinaryNode<string>("ROOT", left, right);

    BinaryTree<string>* tree= new BinaryTree<string>(root);
    cout<<"preOrder: \t";
    tree->preOrder(root);
    cout<<"\ninOrder: \t";
    tree->inOrder(root);
    cout<<"\npostOrder: \t";
    tree->postOrder(root);
    cout<<endl;

    return 0;
}

下面是运行结果：

[email protected]:~/C/DataStructure$ ./BinaryTree.o
preOrder:     ROOT    LEFT    RIGHT1    RIGHT
inOrder:      LEFT    RIGHT1    ROOT    RIGHT
postOrder:    RIGHT1    LEFT    RIGHT    ROOT
[email protected]-ubun:~/C/DataStructure$ 

这个版本是初级版本，遍历采用递归方式。接下来将不断完善！

欢迎交流！