c++ - 尝试在二叉树中分配值时出现段错误

Question

我正在为我的 C++ 类做一个 BinaryTree 项目，但我一直遇到段错误。它不断打破我试图在我的 TreeNode 类中的 setValue() 函数中将 x 分配给值的地方。有谁知道为什么会这样？

这是我的 TreeNode 类:

#ifndef TREENODE_H
#define TREENODE_H
#include <iostream>

template<typename T>
class TreeNode{
private:
    T value;
    TreeNode* left;
    TreeNode* right;
public:
    TreeNode();
    TreeNode(const T&);
    ~TreeNode();
    T& getValue();
    TreeNode* getLeft() const;
    TreeNode* getRight() const;
    void setValue(const T&);
    void setLeft(TreeNode*);
    void setRight(TreeNode*);
};
template<typename T>
TreeNode<T>::TreeNode()
{
    value = 0;
    left = NULL;
    right = NULL;
}
template<typename T>
TreeNode<T>::TreeNode(const T& x)
{
    value = x;
    left = NULL;
    right = NULL;
}
template<typename T>
TreeNode<T>::~TreeNode()
{
    if(left!=NULL)
        delete left;
    if(right!=NULL)
        delete right;
}
template<typename T>
void TreeNode<T>::setValue(const T& x)
{
    value=x;
}
template<typename T>
T& TreeNode<T>::getValue()
{
    return value;
}
template<typename T>
TreeNode<T>* TreeNode<T>::getLeft() const
{
    return left;
}
template<typename T>
TreeNode<T>* TreeNode<T>::getRight() const
{
    return right;
}
template<typename T>
void TreeNode<T>::setLeft(TreeNode* x)
{
    if(left!=NULL)
        delete left;
    left=new TreeNode;
    left=x;
}
template<typename T>
void TreeNode<T>::setRight(TreeNode* x)
{
    if(right!=NULL)
        delete right;
    right=new TreeNode;
    right=x;
}

#endif

这是我的 BinaryTree 类:

#ifndef BINARYTREE_H
#define BINARYTREE_H
#include "TreeNode.h"
#include <iostream>

template<typename T>
class BinaryTree:public TreeNode<T>{
public:
    BinaryTree();
    BinaryTree(const T&);
    ~BinaryTree();
    BinaryTree(const BinaryTree&);
    void insert(const T&);
    void inorder_traversal();
private:
    TreeNode<T>* root;
    TreeNode<T>* getRoot();
    void setRoot(const T&);
    void destroyTree(TreeNode<T>*);
};
template<typename T>
BinaryTree<T>::BinaryTree()
{
    root = new TreeNode <T>;
    root = NULL;
}
template<typename T>
BinaryTree<T>::BinaryTree(const T& x)
{
    root = new TreeNode <T>(x);
}
template<typename T>
BinaryTree<T>::BinaryTree(const BinaryTree<T>& A)
{
    root=A.getRoot();
}
template<typename T>
void BinaryTree<T>::destroyTree(TreeNode<T>* leaf)
{
    if(leaf!=NULL)
    {
        destroyTree(leaf->getLeft());
        destroyTree(leaf->getRight());
        delete leaf;
    }
}
template<typename T>
BinaryTree<T>::~BinaryTree()
{
    if(root!=NULL)
        destroyTree(root);
}
template<typename T>
TreeNode<T>* BinaryTree<T>::getRoot()
{
    return root;
}
template<typename T>
void BinaryTree<T>::setRoot(const T& x)
{
    if(root!=NULL)
    {
        delete root;
        root=new TreeNode<T>;
    }
    root->setValue(x);
}
template<typename T>
void BinaryTree<T>::insert(const T& x)
{
    if (root == NULL)
        setRoot(x);
    else
    {
        TreeNode<T>* rootTemp = new TreeNode < T > ;
        rootTemp = root;
        bool insertionComplete = false;
        while (!insertionComplete)
        {
            if (x < rootTemp->getValue())
            {
                if ((rootTemp->getLeft()) == NULL)
                {
                    (rootTemp->getLeft())->setValue(x);
                    insertionComplete = true;
                }
                else
                    rootTemp = rootTemp->getLeft();
            }
            else
            {
                if ((rootTemp->getRight()) == NULL)
                {
                    (rootTemp->getRight())->setValue(x);
                    insertionComplete = true;
                }
                else
                    rootTemp = rootTemp->getRight();
            }
        }
        root = rootTemp;
        delete rootTemp;
    }
}

#endif

这是我尝试运行的简单 main.cpp:

#include "TreeNode.h"
#include "BinaryTree.h"
#include <iostream>

int main()
{
    BinaryTree<int> x(2);
    std::cout << "first\n";
    x.insert(1);
    std::cout<<"END\n";
    return 0;
}

Answer 1

在你的类(class)里，你有这段代码

if (x < rootTemp->getValue())
            {
                if ((rootTemp->getLeft()) == NULL)
                {
                    (rootTemp->getLeft())->setValue(x);
                    insertionComplete = true;
                }
                else
                    rootTemp = rootTemp->getLeft();
            }
            else
            {
                if ((rootTemp->getRight()) == NULL)
                {
                    (rootTemp->getRight())->setValue(x);
                    insertionComplete = true;
                }
                else
                    rootTemp = rootTemp->getRight();
            }

当对象为 NULL 时，您基本上是在调用 setValue() 的地方。在使用它们之前，您必须从 TreeNode 对象初始化 left 和/或 right