[英]Binary search tree not loading insert values into tree
My problem is trying to get functions treeLeavesCount()
and treeNodeCount()
to return a value of leaves and nodes in the tree but, my issue is after providing values through a while loop using an insert()
function, the tree seems to stay empty and I know this by using an isEmpty()
function before and after inserting values into the tree. 我的问题是尝试让函数treeLeavesCount()
和treeNodeCount()
返回树中的叶子和节点的值,但是,我的问题是在使用insert()
函数通过while循环提供值之后,树似乎保持为空我通过在树中插入值之前和之后使用isEmpty()
函数来知道这一点。
main.cpp main.cpp
#include <iostream>
#include "binaryTreeType.h"
#include "bSearchTreeType.h"
using namespace std;
int main()
{
int num;
bSearchTreeType<int> *myTree= new bSearchTreeType<int>();
//test if tree is empty
if(myTree->isEmpty())
cout << "yes" << endl;
else
cout << "no" << endl;
cout << "Line 10: Enter numbers ending with -999"<< endl;
cin >> num;
while (num != -999)
{
myTree->insert(num);
cin >> num;
}
myTree->inorderTraversal();
int p;
p=myTree->treeNodeCount();
cout << p << endl;
p=myTree->treeLeavesCount();
cout << p << endl;
//test if tree is empty after data is inserted
if(myTree->isEmpty())
cout << "yes" << endl;
else
cout << "no" << endl;
delete myTree;
return 0;
}
binaryTreeType.h binaryTreeType.h
#ifndef BINARYTREETYPE_H
#define BINARYTREETYPE_H
#include <queue>
template <class elemType>
struct binaryTreeNode
{
elemType info;
binaryTreeNode<elemType> *llink;
binaryTreeNode<elemType> *rlink;
};
template <class elemType>
class binaryTreeType
{
public:
const binaryTreeType<elemType>& operator=(const binaryTreeType<elemType>&);
//Overload the assignment operator.
bool isEmpty() const;
//Returns true if the binary tree is empty;
//otherwise, returns false.
void inorderTraversal() const;
//Function to do an inorder traversal of the binary tree.
void preorderTraversal() const;
//Function to do a preorder traversal of the binary tree.
void postorderTraversal() const;
//Function to do a postorder traversal of the binary tree.
int treeHeight() const;
//Returns the height of the binary tree.
int treeNodeCount() const;
//Returns the number of nodes in the binary tree.
int treeLeavesCount() const;
//Returns the number of leaves in the binary tree.
void destroyTree();
//Deallocates the memory space occupied by the binary tree.
//Postcondition: root = NULL;
binaryTreeType(const binaryTreeType<elemType>& otherTree);
//copy constructor
binaryTreeType();
//default constructor
~binaryTreeType();
//destructor
protected:
binaryTreeNode<elemType> *root;
private:
void copyTree(binaryTreeNode<elemType>* &copiedTreeRoot,binaryTreeNode<elemType>* otherTreeRoot);
//Makes a copy of the binary tree to which
//otherTreeRoot points. The pointer copiedTreeRoot
//points to the root of the copied binary tree.
void destroy(binaryTreeNode<elemType>* &p);
//Function to destroy the binary tree to which p points.
//Postcondition: p = NULL
void inorder(binaryTreeNode<elemType> *p) const;
//Function to do an inorder traversal of the binary
//tree to which p points.
void preorder(binaryTreeNode<elemType> *p) const;
//Function to do a preorder traversal of the binary
//tree to which p points.
void postorder(binaryTreeNode<elemType> *p) const;
//Function to do a postorder traversal of the binary
//tree to which p points.
int height(binaryTreeNode<elemType> *p) const;
//Function to return the height of the binary tree
//to which p points.
int max(int x, int y) const;
//Returns the larger of x and y.
int nodeCount(binaryTreeNode<elemType> *p) const;
//Function to return the number of nodes in the binary
//tree to which p points
int leavesCount(binaryTreeNode<elemType> *p) const;
//Function to return the number of leaves in the binary
//tree to which p points
};
template <class elemType>
bool binaryTreeType<elemType>::isEmpty() const
{
return (root == NULL);
};
template <class elemType>
binaryTreeType<elemType>::binaryTreeType()
{
root = NULL;
}
template <class elemType>
void binaryTreeType<elemType>::inorderTraversal() const
{
inorder(root);
}
template <class elemType>
void binaryTreeType<elemType>::preorderTraversal() const
{
preorder(root);
}
template <class elemType>
void binaryTreeType<elemType>::postorderTraversal() const
{
postorder(root);
}
template <class elemType>
int binaryTreeType<elemType>::treeHeight() const
{
return height(root);
}
template <class elemType>
int binaryTreeType<elemType>::treeNodeCount() const
{
return nodeCount(root);
}
template <class elemType>
int binaryTreeType<elemType>::treeLeavesCount() const
{
return leavesCount(root);
}
template <class elemType>
void binaryTreeType<elemType>::inorder(binaryTreeNode<elemType> *p) const
{
if (p != NULL)
{
inorder(p->llink);
std::cout << p->info << " ";
inorder(p->rlink);
}
}
template <class elemType>
void binaryTreeType<elemType>::preorder(binaryTreeNode<elemType> *p) const
{
if (p != NULL)
{
std::cout << p->info << " ";
preorder(p->llink);
preorder(p->rlink);
}
}
template <class elemType>
void binaryTreeType<elemType>::postorder(binaryTreeNode<elemType> *p) const
{
if (p != NULL)
{
postorder(p->llink);
postorder(p->rlink);
std::cout << p->info << " ";
}
}
template <class elemType>
int binaryTreeType<elemType>::height(binaryTreeNode<elemType> *p) const
{
if (p == NULL)
return 0;
else
return 1 + max(height(p->llink), height(p->rlink));
}
template <class elemType>
int binaryTreeType<elemType>::max(int x, int y) const
{
if (x >= y)
return x;
else
return y;
}
template <class elemType>
void binaryTreeType<elemType>::copyTree(binaryTreeNode<elemType>* &copiedTreeRoot,binaryTreeNode<elemType>* otherTreeRoot)
{
if (otherTreeRoot == NULL)
copiedTreeRoot = NULL;
else
{
copiedTreeRoot = new binaryTreeNode<elemType>;
copiedTreeRoot->info = otherTreeRoot->info;
copyTree(copiedTreeRoot->llink, otherTreeRoot->llink);
copyTree(copiedTreeRoot->rlink, otherTreeRoot->rlink);
}
} //end copyTree
template <class elemType>
void binaryTreeType<elemType>::destroy(binaryTreeNode<elemType>* &p)
{
if (p != NULL)
{
destroy(p->llink);
destroy(p->rlink);
delete p;
p = NULL;
}
}
template <class elemType>
void binaryTreeType<elemType>::destroyTree()
{
destroy(root);
}
template <class elemType>
binaryTreeType<elemType>::binaryTreeType(const binaryTreeType<elemType>& otherTree)
{
if (otherTree.root == NULL) //otherTree is empty
root = NULL;
else
copyTree(root, otherTree.root);
}
template <class elemType>
binaryTreeType<elemType>::~binaryTreeType()
{
destroy(root);
}
template <class elemType>
const binaryTreeType<elemType>& binaryTreeType<elemType>::operator=(const binaryTreeType<elemType>& otherTree)
{
if (this != &otherTree) //avoid self-copy
{
if (root != NULL) //if the binary tree is not empty,
//destroy the binary tree
destroy(root);
if (otherTree.root == NULL) //otherTree is empty
root = NULL;
else
copyTree(root, otherTree.root);
}//end else
return *this;
}
template <class elemType>
int binaryTreeType<elemType>::leavesCount(binaryTreeNode<elemType> *p) const
{
if(p == NULL)
return 0;
if(p->llink == NULL && p->rlink==NULL)
return 1;
else
return leavesCount(p->llink) + leavesCount(p->rlink);
}
template <class elemType>
int binaryTreeType<elemType> ::nodeCount(binaryTreeNode<elemType> *p) const
{
int count = 1;
if ( p == NULL ){
return 0;
}else{
count += nodeCount(p->llink);
count += nodeCount(p->rlink);
}
return count;
}
#endif // BINARYTREETYPE_H
bSearchTreeType.h bSearchTreeType.h
#ifndef BSEARCHTREETYPE_H
#define BSEARCHTREETYPE_H
#include "binaryTreeType.h"
#include <iostream>
#include <cassert>
template <class elemType>
class bSearchTreeType : public binaryTreeType<elemType>
{
public:
bool search(const elemType& searchItem) const;
//Function to determine if searchItem is in the binary
//search tree.
//Postcondition: Returns true if searchItem is found in the
// binary search tree; otherwise, returns false.
void insert(const elemType& insertItem);
//Function to insert insertItem in the binary search tree.
//Postcondition: If no node in the binary search tree has the
// same info as insertItem, a node with the info insertItem
// is created and inserted in the binary search tree.
void deleteNode(const elemType& deleteItem);
//Function to delete deleteItem from the binary search tree.
//Postcondition: If a node with the same info as deleteItem
// is found, it is deleted from the binary search tree.
protected:
binaryTreeNode<elemType> *root;
private:
void deleteFromTree(binaryTreeNode<elemType>* &p);
//Function to delete the node to which p points is deleted
//from the binary search tree.
//Postcondition: The node to which p points is deleted from
// the binary search tree.
};
using namespace std;
template <class elemType>
bool bSearchTreeType<elemType>::search(const elemType& searchItem) const
{
binaryTreeNode<elemType> *current;
bool found = false;
if (root == NULL)
cerr << "Cannot search the empty tree." << endl;
else
{
current = root;
while (current != NULL && !found)
{
if (current->info == searchItem)
found = true;
else if (current->info > searchItem)
current = current->llink;
else
current = current->rlink;
}//end while
}//end else
return found;
}//end search
template <class elemType>
void bSearchTreeType<elemType>::insert(const elemType& insertItem)
{
binaryTreeNode<elemType> *current; //pointer to traverse the tree
binaryTreeNode<elemType> *trailCurrent; //pointer behind current
binaryTreeNode<elemType> *newNode; //pointer to create the node
newNode = new binaryTreeNode<elemType>;
assert(newNode != NULL);
newNode->info = insertItem;
newNode->llink = NULL;
newNode->rlink = NULL;
if (root == NULL)
root = newNode;
else
{
current = root;
while (current != NULL)
{
trailCurrent = current;
if (current->info == insertItem)
{
std::cerr << "The insert item is already in the list-";
std::cerr << "duplicates are not allowed." << insertItem << std::endl;
return;
}
else if (current->info > insertItem)
current = current->llink;
else
current = current->rlink;
}//end while
if (trailCurrent->info > insertItem)
trailCurrent->llink = newNode;
else
trailCurrent->rlink = newNode;
}
}//end insert
template <class elemType>
void bSearchTreeType<elemType>::deleteFromTree(binaryTreeNode<elemType>* &p)
{
binaryTreeNode<elemType> *current;//pointer to traverse the tree
binaryTreeNode<elemType> *trailCurrent; //pointer behind current
binaryTreeNode<elemType> *temp; //pointer to delete the node
if (p == NULL)
cerr << "Error: The node to be deleted is NULL." << endl;
else if(p->llink == NULL && p->rlink == NULL)
{
temp = p;
p = NULL;
delete temp;
}
else if(p->llink == NULL)
{
temp = p;
p = temp->rlink;
delete temp;
}
else if(p->rlink == NULL)
{
temp = p;
p = temp->llink;
delete temp;
}
else
{
current = p->llink;
trailCurrent = NULL;
while (current->rlink != NULL)
{
trailCurrent = current;
current = current->rlink;
}//end while
p->info = current->info;
if (trailCurrent == NULL) //current did not move;
//current == p->llink; adjust p
p->llink = current->llink;
else
trailCurrent->rlink = current->llink;
delete current;
}//end else
}//end deleteFromTree
template <class elemType>
void bSearchTreeType<elemType>::deleteNode(const elemType& deleteItem)
{
binaryTreeNode<elemType> *current; //pointer to traverse the tree
binaryTreeNode<elemType> *trailCurrent; //pointer behind current
bool found = false;
if (root == NULL)
std::cout << "Cannot delete from the empty tree." << endl;
else
{
current = root;
trailCurrent = root;
while (current != NULL && !found)
{
if (current->info == deleteItem)
found = true;
else
{
trailCurrent = current;
if (current->info > deleteItem)
current = current->llink;
else
current = current->rlink;
}
}//end while
if (current == NULL)
std::cout << "The delete item is not in the tree." << endl;
else if (found)
{
if (current == root)
deleteFromTree(root);
else if (trailCurrent->info > deleteItem)
deleteFromTree(trailCurrent->llink);
else
deleteFromTree(trailCurrent->rlink);
}//end if
}
}//end deleteNode
#endif // BSEARCHTREETYPE_H
(That's a humongous amount of code. Please remove everything your test case doesn't need next time.) (这是大量的代码。请删除您的测试用例下次不需要的所有内容。)
Cutting your code down to the bare essentials, we get 将您的代码精简到最基本的要求,我们得到了
template <class elemType>
class binaryTreeType
{
public:
bool isEmpty() const;
protected:
binaryTreeNode<elemType> *root;
};
template <class elemType>
bool binaryTreeType<elemType>::isEmpty() const
{
return (root == NULL);
};
template <class elemType>
class bSearchTreeType : public binaryTreeType<elemType>
{
void insert(const elemType& insertItem);
protected:
binaryTreeNode<elemType> *root;
};
template <class elemType>
void bSearchTreeType<elemType>::insert(const elemType& insertItem)
{
// ...
if (root == NULL)
root = newNode;
else
{
current = root;
//...
}
}//end insert
And now we can see that you declare two member variables called "root". 现在我们可以看到您声明了两个名为“ root”的成员变量。
The one in bSearchTreeType
hides the one in binaryTreeType
- it's not a redeclaration or "override" of the same variable. 在一个bSearchTreeType
隐藏了一个在binaryTreeType
-它不是一个重声明或同一变量的“覆盖”。
This means that your binaryTreeType
member functions (such as isEmpty
) use the root
in binaryTreeType
, while the member functions of bSearchTreeType
(such as insert
) use the root
in bSearchTreeType
, so after insert
has updated one of the roots the other one is still null. 这意味着你的binaryTreeType
成员函数(如isEmpty
)使用的root
在binaryTreeType
,而成员函数bSearchTreeType
(如insert
)使用的root
在bSearchTreeType
,所以之后insert
已更新的根源之一,另一个仍然为空。
Incidentally, this issue is also difficult to discover with a debugger, where you'll just be staring at a variable whose value changes as if by magic. 顺便提一句,使用调试器也很难发现这个问题,在调试器中,您只能盯着一个变量,其值会像魔术般变化。
You need to do two things: 您需要做两件事:
root
member from bSearchTreeType
从bSearchTreeType
删除root
成员 root
to this->root
in the bSearchTreeType
member functions. 因为这些都是模板,你也需要改变root
到this->root
在bSearchTreeType
成员函数。 (Finding out why left as an exercise - it's an essay of its own.) (找出为什么要离开做练习-这是一篇自己的论文。) (It seems to work with just these changes, by the way. Well done.) (顺便说一下,这似乎仅适用于这些更改。做得很好。)
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