我搜索了论坛，并尝试在我找到的主题中实现代码。但是我从上午10点开始就一直在研究这个真正简单的程序，并且无法解决这个问题。我生命的错误。
任何关于我做错事的想法都将不胜感激。
BST.h（所有的实现问题都应该在这里，并且已经更新了一些，以反映进一步的开发工作，查看历史记录以查看旧版本。）
#ifndef BST_H_
#define BST_H_
#include <stdexcept>
#include <iostream>
#include "btnode.h"
using namespace std;
/*
A class to represent a templated binary search tree.
*/
template <typename T>
class BST
{
private:
//pointer to the root node in the tree
BTNode<T>* root;
public:
//default constructor to make an empty tree
BST();
/*
You have to document these 4 functions
*/
void insert(T value);
bool search(const T& value) const;
bool search(BTNode<T>* node, const T& value) const;
void printInOrder() const;
void remove(const T& value);
//function to print out a visual representation
//of the tree (not just print the tree's values
//on a single line)
void print() const;
private:
//recursive helper function for "print()"
void print(BTNode<T>* node,int depth) const;
};
/*
Default constructor to make an empty tree
*/
template <typename T>
BST<T>::BST()
{
root = NULL;
}
template <typename T>
void BST<T>::insert(T value)
{
BTNode<T>* newNode = new BTNode<T>(value);
cout << newNode->data;
if(root == NULL)
{
root = newNode;
return;
}
BTNode<T>* current = root;
while(true)
{
if(current->left == NULL && current->right == NULL)
break;
if(current->right != NULL && current->left != NULL)
{
if(newNode->data > current->data)
current = current->right;
else if(newNode->data < current->data)
current = current->left;
}
else if(current->right != NULL && current->left == NULL)
{
if(newNode->data < current->data)
break;
else if(newNode->data > current->data)
current = current->right;
}
else if(current->right == NULL && current->left != NULL)
{
if(newNode->data > current->data)
break;
else if(newNode->data < current->data)
current = current->left;
}
}
if(current->data > newNode->data)
{
current->left = newNode;
/* cout << current->data << "DATA" << endl;
cout << ¤t << "ADDY" << endl;
cout << ¤t->left << "L ADDY" << endl;
cout << ¤t->right << "R ADDY" << endl;*/
}
else
{
current->right = newNode;
/*cout << current->data << "DATA" << endl;
cout << ¤t << "ADDY" << endl;
cout << ¤t->left << "L ADDY" << endl;
cout << ¤t->right << "R ADDY" << endl;*/
}
return;
}
//public helper function
template <typename T>
bool BST<T>::search(const T& value) const
{
return(search(root,value)); //start at the root
}
//recursive function
template <typename T>
bool BST<T>::search(BTNode<T>* node, const T& value) const
{
if(node == NULL || node->data == value)
return(node != NULL); //found or couldn't find value
else if(value < node->data)
return search(node->left,value); //search left subtree
else
return search(node->right,value); //search right subtree
}
template <typename T>
void BST<T>::printInOrder() const
{
//print out the value's in the tree in order
//
//You may need to use this function as a helper
//and create a second recursive function
//(see "print()" for an example)
}
template <typename T>
void BST<T>::remove(const T& value)
{
if(root == NULL)
{
cout << "Tree is empty. No removal. "<<endl;
return;
}
if(!search(value))
{
cout << "Value is not in the tree. No removal." << endl;
return;
}
BTNode<T>* current = root;
BTNode<T>* parent;
cout << root->data << " ROOT" << endl;
cout << current->data << "CURRENT BEFORE" << endl;
while(current != NULL)
{
if(root->data == value)
{
delete current;
return;
}
else if(value > current->data)
{
parent = current;
current = current->right;
}
else
{
parent = current;
current = current->left;
}
}
cout << current->data << "CURRENT AFTER" << endl;
// 3 cases :
//We're looking at a leaf node
if(current->left == NULL && current->right == NULL) // It's a leaf
{
if(parent == current)
delete parent;
else if(parent->left == current)
{
parent->left = NULL;
delete current;
}
else
{
parent->right = NULL;
delete current;
}
cout << "The value " << value << " was removed." << endl;
return;
}
// Node with single child
if((current->left == NULL && current->right != NULL) || (current->left != NULL && current->right == NULL))
{
if(current->left == NULL && current->right != NULL)
{
if(parent->left == current)
{
parent->left = current->right;
cout << "The value " << value << " was removed." << endl;
delete current;
}
else
{
parent->right = current->right;
cout << "The value " << value << " was removed." << endl;
delete current;
}
}
else // left child present, no right child
{
if(parent->left == current)
{
parent->left = current->left;
cout << "The value " << value << " was removed." << endl;
delete current;
}
else
{
parent->right = current->left;
cout << "The value " << value << " was removed." << endl;
delete current;
}
}
return;
}
//Node with 2 children - Replace node with smallest value in right subtree.
if (current->left != NULL && current->right != NULL)
{
BTNode<T>* check;
check = current->right;
if((check->left == NULL) && (check->right == NULL))
{
current = check;
delete check;
current->right = NULL;
cout << "The value " << value << " was removed." << endl;
}
else // right child has children
{
//if the node's right child has a left child; Move all the way down left to locate smallest element
if((current->right)->left != NULL)
{
BTNode<T>* leftCurrent;
BTNode<T>* leftParent;
leftParent = current->right;
leftCurrent = (current->right)->left;
while(leftCurrent->left != NULL)
{
leftParent = leftCurrent;
leftCurrent = leftCurrent->left;
}
current->data = leftCurrent->data;
delete leftCurrent;
leftParent->left = NULL;
cout << "The value " << value << " was removed." << endl;
}
else
{
BTNode<T>* temp;
temp = current->right;
current->data = temp->data;
current->right = temp->right;
delete temp;
cout << "The value " << value << " was removed." << endl;
}
}
return;
}
}
/*
Print out the values in the tree and their
relationships visually. Sample output:
22
18
15
10
9
5
3
1
*/
template <typename T>
void BST<T>::print() const
{
print(root,0);
}
template <typename T>
void BST<T>::print(BTNode<T>* node,int depth) const
{
if(node == NULL)
{
std::cout << std::endl;
return;
}
print(node->right,depth+1);
for(int i=0; i < depth; i++)
{
std::cout << "\t";
}
std::cout << node->data << std::endl;
print(node->left,depth+1);
}
#endif
main.cpp
#include "bst.h"
#include <iostream>
using namespace std;
int main()
{
BST<int> tree;
cout << endl << "LAB #13 - BINARY SEARCH TREE PROGRAM" << endl;
cout << "----------------------------------------------------------" << endl;
// Insert.
cout << endl << "INSERT TESTS" << endl; // No duplicates allowed.
tree.insert(0);
tree.insert(5);
tree.insert(15);
tree.insert(25);
tree.insert(20);
// Search.
cout << endl << "SEARCH TESTS" << endl;
int x = 0;
int y = 1;
if(tree.search(x))
cout << "The value " << x << " is on the tree." << endl;
else
cout << "The value " << x << " is NOT on the tree." << endl;
if(tree.search(y))
cout << "The value " << y << " is on the tree." << endl;
else
cout << "The value " << y << " is NOT on the tree." << endl;
// Removal.
cout << endl << "REMOVAL TESTS" << endl;
tree.remove(0);
tree.remove(1);
tree.remove(20);
// Print.
cout << endl << "PRINTED DIAGRAM OF BINARY SEARCH TREE" << endl;
cout << "----------------------------------------------------------" << endl;
tree.print();
cout << endl << "Program terminated. Goodbye." << endl << endl;
}
BTNode.h
#ifndef BTNODE_H_
#define BTNODE_H_
#include <iostream>
/*
A class to represent a node in a
binary search tree.
*/
template <typename T>
class BTNode
{
public:
//constructor
BTNode(T d);
//the node's data value
T data;
//pointer to the node's left child
BTNode<T>* left;
//pointer to the node's right child
BTNode<T>* right;
};
/*
Simple constructor. Sets the data
value of the BTNode to "d" and defaults its
left and right child pointers to NULL.
*/
template <typename T>
BTNode<T>::BTNode(T d)
: left(NULL), right(NULL)
{
data = d;
}
#endif
感谢。
答案 0 :(得分：8)
insert有内存泄漏。这三行：
BTNode<T>* current = new BTNode<T>(NULL);
current = root;
current->data = root->data;
应为：
BTNode<T>* current = root;
整个功能有一些扭曲的逻辑，可以通过仔细考虑并压缩它们，将其压缩到当前大小的1/4左右。
另外，这里有一个提示，说明为什么你要删除段错误。这很明显，并不是因为代码的任何其他部分都被破坏了。调试器是你的朋友。
提示是，这段代码在remove中做了什么？仔细想想：
BTNode<T>* current;
BTNode<T>* parent;
current = root;
parent->left = NULL;
parent->right = NULL;
答案 1 :(得分：4)
既然是家庭作业，我会帮你自己帮忙。您应该做的第一个事情就是编写一个dump函数，该函数以可读的形式吐出树，显示每个节点：
然后在每次插入和删除后调用dump函数。这是标准调试101，如果您愿意，您可以保留该代码。如果您向他们展示您有智能编写单元测试代码，它可能会从您的教育工作者那里获得更多分数。