普通树（有根树）C++

对于普通树实现的细节包括

1 树结点的结构体

2 初始化及删除树结点（关注内存泄露）

3 递归先序遍历

4 通过关键值的查询操作，返回关键值的结点

5 凹入表实现

6 广义表实现

7 非递归先序遍历，利用栈作为辅助的数据结构

#include <iostream>
#include <crtdbg.h>
#include <cstring>
#include <assert.h>
using namespace std;

typedef int DataType;
struct TreeNode
{
    TreeNode()
    {
        sibling = NULL;
        child = NULL;
    }
    DataType data;
    TreeNode * sibling; //右兄弟结点
    TreeNode * child;   //左子结点
};
typedef TreeNode *DataStack; // 存储类型为 TreeNode*
//普通树
class Tree
{
private:
    TreeNode *root;
    Tree(const Tree &) {}//防止拷贝构造 与 赋值
    Tree & operator=(const Tree &) { return *this; }
public:
    Tree(const DataType &data);
    ~Tree();
    const TreeNode * GetRoot()const { return root;}
    TreeNode * GetRoot() { return root;}
    void Init(const DataType &data);
    void Destroy(TreeNode * p);//删除根结点
    void DestroySub(TreeNode * p);//删除子结点;
    TreeNode * InsertChild(TreeNode *p, DataType data);
    TreeNode * InsertSibling(TreeNode *p, DataType data);
    void Print(const TreeNode * p); //先序遍历
    TreeNode *  Find(TreeNode * p, DataType data);//寻找data返回并返回结点
    void Print2(); //非递归先序遍历
};
//辅助类栈
class Stack
{
private:
    struct Node
    {
        DataStack data;
        Node *next;
    };
    Node * head;
    void Init()
    {
        head = NULL;
    }
    void Destroy()
    {
        for (Node* p = head; p != NULL;)
        {
            Node *pTemp = p->next;
            delete p ;
            p = pTemp;
        }
        head = NULL;
    }
public:
    Stack()
    {
        Init();
    }
    ~Stack()
    {
        Destroy();
    }
    void Push(DataStack  data)
    {
        Node *p = new Node;
        p->data = data;
        p->next = head;
        head = p;
    }
    DataStack Pop()
    {
        if (head == NULL)
        {
            return NULL;
        }
        Node *p = head;
        DataStack temp = p->data;
        head = head->next;
        delete p;
        p = NULL;
        return temp;
    }
    int Getlenth()
    {
        int n = 0;
        for (Node *p = head; p != NULL; p = p->next)
        {
            ++n;
        }
        return n;
    }
    DataStack Getop()
    {
        if (head == NULL)
        {
            return NULL;
        }
        return head->data;
    }
    bool Empty()
    {
        return (head == NULL);
    }
};
//普通树方法实现
Tree::Tree(const DataType &data) 
{
    Init(data);
}
Tree::~Tree () 
{ 
    Destroy(root);
}
void Tree::Init(const DataType &data)
{
    root = new TreeNode;
    root->child = NULL;
    root->sibling = NULL;
    root->data = data;
}
void Tree::Destroy(TreeNode * p)
{
    if (p == NULL)
    {
        return;
    }
    Destroy(p->sibling);
    Destroy(p->child);
    delete p;
    p = NULL;
}
void Tree::DestroySub(TreeNode * p)
{
    if (p->child)
    {
        Destroy(p->child);
        p->child = NULL;
    }
}
TreeNode * Tree::InsertChild(TreeNode * p, DataType data)
{
    if (p->child)
    {
        return p->child; //已有子结点
    }
    TreeNode *pNew = new TreeNode;
    pNew->data = data;
    p->child = pNew;
    return pNew;
}
TreeNode * Tree::InsertSibling(TreeNode * p, DataType data)
{
    if (p->sibling) 
    {
        return p->sibling;//已有兄弟结点
    }
    TreeNode *pNew = new TreeNode;
    pNew->data = data;
    p->sibling = pNew;
    return pNew;
}
//先序遍历
void  Tree::Print(const TreeNode * p)
{
    if(p==NULL)
    {
        return;
    }
    cout << p->data << endl;
    Print(p->child);
    Print(p->sibling);
}
//寻找data并返回结点
 TreeNode *  Tree::Find(TreeNode * p, DataType data)
{
    if(p == NULL)
        return NULL;
    if (p->data == data)
    {
        return p;
    }
    TreeNode *pFind = Find(p->child, data);
    if (pFind != NULL)
    {    
        return pFind;
    }

    return Find(p->sibling, data);
}
//非递归先序遍历
void Tree::Print2()
{
    TreeNode *p = GetRoot();
    if (p == NULL)
    {
        return;
    }
    Stack stack;
    
    while( (p != NULL) || (!stack.Empty()) )
    {
        if (p != NULL)
        {
            cout << p->data << endl;
            stack.Push(p);
            p = p->child;
        }
        else
        {
             p = stack.Pop();
             p = p->sibling;
        }
    }
}
void AoRuBiao(const TreeNode *p, int depth)
{
    if (p == NULL)
    {
        return;
    }
    for (int i=0; i<depth; ++i)
    {
        cout << " ";
    }
    cout << p->data;
    for (int i=0; i<10-depth; ++i)
    {
        cout << " - ";
    }
    cout << endl;
    AoRuBiao(p->child, depth+1);
    AoRuBiao(p->sibling, depth);
}
void GuangYiBiao(const TreeNode *p)
{
    if (p == NULL)
    {
        return;
    }
    cout << p->data;
    if (p->child)
    {
        cout << "(";
    }
    GuangYiBiao(p->child);
    if (p->child)
    {
        cout << ")";
    }
    if (p->sibling)
    {
        cout << ",";
    }
    GuangYiBiao(p->sibling);
}

void main()
{
    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);

    Tree tree(10);

    //Stack s;
    //s.Push(tree.GetRoot());
    //cout << s.Getop()->data;

    TreeNode * p11 = tree.InsertChild(tree.GetRoot(), 11);
    TreeNode * p12 = tree.InsertSibling(p11,12);
    TreeNode * p13 = tree.InsertSibling(p12,13);

    TreeNode * p111 = tree.InsertChild(p11, 111);
    TreeNode * p112 = tree.InsertSibling(p111,112);

    TreeNode * p121 = tree.InsertChild(p12, 121);
    TreeNode * p122 = tree.InsertSibling(p121,122);

    tree.Print(tree.GetRoot());
    //tree.DestroySub(p12);
    //tree.Print(tree.GetRoot());
    cout << "

Search p12" << endl;
    TreeNode * temp = tree.Find(tree.GetRoot(),12);
    if (temp != NULL)
    {
        cout << temp->child->data <<endl;
        cout << temp->sibling->data << endl;
    }

    cout << "

AoRuBiao " << endl;
    AoRuBiao(tree.GetRoot(),1);
    
    cout << "
GuangYiBiao" << endl;
    GuangYiBiao(tree.GetRoot());

    cout << "

非递归遍历" << endl;
    tree.Print2();

    system("pause");
} 

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