Question

我有一个工作正常的AVL树，我的程序包含一个“ TreeType.h”文件和一个“ main.cpp”（我将在下面附加代码）。在main.cpp中，我按以下顺序将字符串插入AVL树：

tree.InsertItem("dean");
tree.InsertItem("joe");
tree.InsertItem("jason");

这很好用，但是如果我停止程序并切换数据，以便插入的字符串如下：

tree.InsertItem("joe");
tree.InsertItem("dean");
tree.InsertItem("jason");

然后我再次运行该程序，然后得到以下运行时错误'（线程1：EXC_BAD_ACCESS（code = 1，address = 0x28））'我不知道这是什么意思或如何按原样纠正它对编程而言相对较新。

TreeType.h

#ifndef AvlClass_h
#define AvlClass_h
#include <iostream>
using namespace std;
typedef enum {LH,EH,RH} Balfactor;

template <class ItemType>
struct TreeNode
{
    ItemType info;
    TreeNode *left;
    TreeNode *right;
    Balfactor bf;
};

template <class ItemType>
class TreeType
{
public:
    void InsertItem(ItemType item);
    void Print();
private:
    TreeNode <ItemType> * root;
};

template <class ItemType>
void TreeType<ItemType> ::Print()
{
    PrintPostorder(root);
}

template <class ItemType>
void PrintPostorder(TreeNode<ItemType>*&  tree)
{
    if (tree == NULL)
        return;
    // first recur on left subtree
    PrintPostorder(tree->left);

    // then recur on right subtree
    PrintPostorder(tree->right);

    // now deal with the node
    cout << tree->info << "\n";
}


template <class ItemType>
void TreeType<ItemType> :: InsertItem(ItemType item)
// Calls recursive function Insert to insert item into tree.
{
    bool taller=false;
    Insert (root, item, taller);
}

template <class ItemType>
void Insert (TreeNode<ItemType>*& tree, ItemType item, bool & taller)
// Inserts item into tree.
// Post:item is in tree; search property is maintained.
{
    if (tree == NULL)
    {    // Insertion place found.
        tree = new TreeNode<ItemType>;
        tree->left = NULL;
        tree->right = NULL;
        tree->info = item;
        tree->bf = EH;
        taller = true;
    }
    else if ( item == tree->info)
        cerr << "Duplicate key is not allowed in AVL tree." << endl;
    else if (item < tree->info)
    {
        Insert (tree->left, item, taller);
        // Insert into left subtree
        if (taller)
            switch (tree->bf)
        {
            case LH: LeftBalance(tree,taller);
                break;
            case EH: tree->bf = LH;
                break;
            case RH: tree->bf = EH;
                taller = false;
                break;
        }
    }
    else
    {
        Insert (tree->right, item, taller);
        // Insert into right subtree
        if (taller)
            switch (tree->bf)
        {
            case RH: RightBalance (tree,taller);
                break;
            case EH: tree->bf = RH;
                break;
            case LH: tree->bf = EH;
                taller = false;
                break;
        }

    }
}

template <class ItemType>
void RotateLeft (TreeNode<ItemType> * & tree)
{
    TreeNode<ItemType> * rs;
    if (tree == NULL)
        cerr << "It is impossible to rotate an empty tree in RotateLeft" << endl;
    else if (tree->right == NULL)
        cerr << "It is impossible to make an empty subtree the root in RotateLeft" << endl;
    else
    {
        rs = tree->right;
        tree->right = rs->left;
        rs->left = tree;
        tree = rs;

    }
}

template <class ItemType>
void RotateRight (TreeNode<ItemType> * & tree)
{
    TreeNode<ItemType> * ls;
    if (tree == NULL)
        cerr << "It is impossible to rotate an empty tree in RotateRight" << endl;
    else if (tree->left == NULL)
        cerr << "It is impossible to make an empty subtree the root in RotateRight" << std::endl;
    else
    {
        ls = tree->left;
        tree->left = ls->right;
        ls->right = tree;
        tree = ls;

    }

}

template <class ItemType>
void RightBalance (TreeNode<ItemType> *& tree, bool & taller)
{
    TreeNode<ItemType> * rs = tree->right;
    TreeNode<ItemType> * ls;
    switch (rs->bf)
    {
        case RH:
            tree->bf = rs->bf = EH;
            RotateLeft(tree);
            taller = false;
            break;
        case EH:
            std::cerr << "Tree already balanced " << std::endl;
            break;
        case LH:
            ls = rs->left;
            switch (ls->bf)
        {
            case RH:
                tree->bf = LH;
                rs->bf = EH;
                break;
            case EH:
                tree->bf = rs->bf = EH;
                break;
            case LH:
                tree->bf = EH;
                rs->bf = RH;
                break;
        }
            ls->bf = EH;
            RotateRight(tree->right);
            RotateLeft(tree);
            taller = false;
    }
}


template <class ItemType>
void LeftBalance (TreeNode<ItemType> *& tree, bool & taller)
 {
     TreeNode<ItemType> * ls = tree->left;
     TreeNode<ItemType> * rs;
     switch (ls->bf)
     {
         case LH:
             tree->bf = ls->bf = EH;
             RotateRight(tree);
             taller = false;
             break;
         case EH:
             cerr << "Tree already balanced " << endl;
             break;
         case RH:
             rs = ls->left;
             switch (rs->bf)
         {
             case LH:
                 tree->bf = RH;
                 ls->bf = EH;
                 break;
             case EH:
                 tree->bf = ls->bf = EH;
                 break;
             case RH:
                 tree->bf = EH;
                 ls->bf = LH;
                 break;

         }
             rs->bf = EH;
             RotateLeft(tree->left);
             RotateRight(tree);
             taller = false;
     }

 }
#endif /* AvlClass_h */

main.cpp

#include <iostream>
#include "TreeType.h"
using namespace std;

TreeType<string>tree;

int main(int argc, const char * argv[]) {

    int option;
    do
    {
        cout << "\t1. Insert into an AVL Tree\n";
        cout << "\t2. Print the contents of the AVL tree\n";
        cout << "\t3. Exit\n";
        cout << "\t\tEnter option : ";
        cin >> option;

        switch (option)
        {
            case 1:
                //Insert
                tree.InsertItem("dean");
                tree.InsertItem("joe");
                tree.InsertItem("jason");
                break;
            case 2:
                tree.Print();
                break;
        }

    } while (option < 3);
    return 0;
}

Answer 1

问题是我的LeftBalance函数，我从

更改了LeftBalance函数中的以下代码行

{% extends "base.html" %}
{% load static %}

{% block title %}{{title}}{% endblock title %}

{% block sidenav %}
    {% for page in page_list %}
    <li>
        <a href="{{page.permalink}}">{{page.title}}</a>
    </li>
    {% endfor %}
{% endblock sidenav %}
{% block content %}
{% autoescape off %}
{{ content }}
{% endautoescape %}

{% if bom_list %}
{% for bom in bom_list %}

<table>
    <tr>
        <th><h1>RFQ Number</h1></th>
        <th><h1>BOM</h1></th>
    </tr>
    <tr>
        <td>


            <ul style="list-style-type:none">
                <li>{{ bom.rfq_num }}</li>
            </ul>
        </td>
        <td>
            <ul style="list-style-type:none">
                <li>{{ bom.bom }}</li>
            </ul>
        </td>
        <td>
            <ul style="list-style-type:none">
                <li>{{ bom.part_num }}</li>
            </ul>
        </td>
    </tr>
</table>
{% endfor %}
{% else %}
    <p>No Matching RFQ in Database</p>
{% endif %}

{% endblock content %}

到

case RH:
rs = ls->left;
switch (rs->bf)

AVL树字符串插入错误（线程1：EXC_BAD_ACCESS（代码= 1，地址= 0x28））

1 个答案: