Question

我正在尝试为作业编写这些函数，但我无法弄清楚这些错误的来源或含义。我有2个类，一个用于节点，一个用于二叉树。我最近在我的main函数中添加了一些函数及其实现，并且它们引起了问题（我认为主要是调用私有函数的公共函数）。如果函数声明看起来很奇怪，我道歉，它们是由我的教师编写的，所以我无法真正改变它们。这是我正在使用的功能（我已经删除了不相关或新的功能）：

template < class T > class binTree {
public:
binTree ( ) { // default constructor
    root = NULL;
}
binTree ( const binTree<T>& Right ) {   // Copy Constructor
    root = copy(Right.root);
}
virtual ~binTree () {   // Destructor
    clear(root);
}
binTree<T>& operator = (const binTree<T>& Right) {  // assignment operator
    if (root != NULL)
        clear(root);
    root = copy(Right.root);
    return *this;
}
void clear () {
    clear(root);
}
protected:
binTreeNode < T >* root; // root of tree
private:
void clear (binTreeNode <T>*& p) {
    if (p != NULL) {
        clear(p->left);
        clear(p->right);
        delete p;
        p = NULL;
    }
}
binTreeNode<T>* copy(const binTreeNode<T>* p) {
    if ( p != NULL ) {
        binTreeNode<T>* newNode;
        newNode = new binTreeNode<T>(*p); // modified
        newNode->left = copy(p->left);
        newNode->right = copy(p->right);
        return newNode;
    }
        return NULL; // Added 
}

这是我编译器给我的难以理解的垃圾：

In file included from prog7.cc:2:0:
binTree.h: In member function ‘binTreeNode<T>* binTree<T>::copy(const binTreeNode<T>*) [with T = int]’:
binTree.h:16:3:   instantiated from ‘binTree<T>::binTree(const binTree<T>&) [with T = int]’
prog7.cc:13:36:   instantiated from here
binTree.h:96:4: error: invalid conversion from ‘const binTreeNode<int>*’ to ‘int’ [-fpermissive]
binTreeNode.h:12:2: error:   initializing argument 1 of ‘binTreeNode<T>::binTreeNode(const T&, binTreeNode<T>*, binTreeNode<T>*) [with T = int]’ [-fpermissive]
binTree.h: In member function ‘binTreeNode<T>* binTree<T>::copy(const binTreeNode<T>*) [with T = float]’:
binTree.h:24:3:   instantiated from ‘binTree<T>& binTree<T>::operator=(const binTree<T>&) [with T = float]’
prog7.cc:29:14:   instantiated from here
binTree.h:96:4: error: no matching function for call to ‘binTreeNode<float>::binTreeNode(const binTreeNode<float>*&)’
binTree.h:96:4: note: candidates are:
binTreeNode.h:12:2: note: binTreeNode<T>::binTreeNode(const T&, binTreeNode<T>*, binTreeNode<T>*) [with T = float]
binTreeNode.h:12:2: note:   no known conversion for argument 1 from ‘const binTreeNode<float>*’ to ‘const float&’
binTreeNode.h:8:28: note: binTreeNode<float>::binTreeNode(const binTreeNode<float>&)
binTreeNode.h:8:28: note:   no known conversion for argument 1 from ‘const binTreeNode<float>*’ to ‘const binTreeNode<float>&’
binTree.h: In member function ‘binTreeNode<T>* binTree<T>::copy(const binTreeNode<T>*) [with T = std::basic_string<char>]’:
binTree.h:16:3:   instantiated from ‘binTree<T>::binTree(const binTree<T>&) [with T = std::basic_string<char>]’
prog7.cc:39:30:   instantiated from here
binTree.h:96:4: error: no matching function for call to ‘binTreeNode<std::basic_string<char> >::binTreeNode(const binTreeNode<std::basic_string<char> >*&)’
binTree.h:96:4: note: candidates are:
binTreeNode.h:12:2: note: binTreeNode<T>::binTreeNode(const T&, binTreeNode<T>*, binTreeNode<T>*) [with T = std::basic_string<char>]
binTreeNode.h:12:2: note:   no known conversion for argument 1 from ‘const binTreeNode<std::basic_string<char> >*’ to ‘const std::basic_string<char>&’
binTreeNode.h:8:28: note: binTreeNode<std::basic_string<char> >::binTreeNode(const binTreeNode<std::basic_string<char> >&)
binTreeNode.h:8:28: note:   no known conversion for argument 1 from ‘const binTreeNode<std::basic_string<char> >*’ to ‘const binTreeNode<std::basic_string<char> >&’
binTree.h: In member function ‘binTreeNode<T>* binTree<T>::copy(const binTreeNode<T>*) [with T = int]’:
binTree.h:101:2: warning: control reaches end of non-void function [-Wreturn-type]
binTree.h: In member function ‘binTreeNode<T>* binTree<T>::copy(const binTreeNode<T>*) [with T = float]’:
binTree.h:101:2: warning: control reaches end of non-void function [-Wreturn-type]
binTree.h: In member function ‘binTreeNode<T>* binTree<T>::copy(const binTreeNode<T>*) [with T = std::basic_string<char>]’:
binTree.h:101:2: warning: control reaches end of non-void function [-Wreturn-type]

有谁可以看到我在这几个功能中做错了什么？我完全是在画空白。

编辑::现在，当我调用我的复制构造函数时，我遇到了分段错误，但它确实编译了。根据请求，这是binTreeNode的代码，但它仅供参考，我知道它工作正常。

#pragma once
template < class T > class binTree;
template < class T > class binTreeNode {
friend class binTree < T >;
public:
    // default constructor
    binTreeNode ( const T& newData =T( ), binTreeNode < T >* newLeft = 0, binTreeNode < T >* newRight = 0 ) {
        data = newData;
        left = newLeft;
        right = newRight;
    }
private:
    T data; // data value in node
    binTreeNode < T > *left, *right; // links to other nodes
};

Answer 1

我想你需要在复制方法中返回p == NULL中的某些内容：

binTreeNode<T>* newNode = NULL;
if ( p != NULL ) {
    newNode = new binTreeNode<T>(p);
    newNode->left = copy(p->left);
    newNode->right = copy(p->right);
}
return newNode;

在C ++中，通常使用0代替NULL。

Answer 2

错误总是引用binTreeNode。为什么不向我们展示有关binTreeNode定义的代码？

Answer 3

这里至少有一个错误：

binTreeNode<T>* copy(const binTreeNode<T>* p) {
    if ( p != NULL ) {
        binTreeNode<T>* newNode;
        newNode = new binTreeNode<T>(p);

如果您正在尝试制作p的深层副本，则需要在复制构造函数中取消引用它：

        newNode = new binTreeNode<T>(*p);

二进制树复制构造函数的编译器错误

3 个答案: