二叉查找树的简单C++实现

#pragma once

template <typename Comparable>
class BinarySearchTree
{
public:
BinarySearchTree();
BinarySearchTree(const BinarySearchTree &rhs);
~BinarySearchTree()
{
makeEmpty();
}

const Comparable &findMin() const;
const Comparable &findMax() const;

bool contains(const Comparable &x) const
{
return contains(x,root);
}

bool isEmpty() const;
void printTree() const;

void makeEmpty();

void insert(const Comparable &x)
{
insert(x,root);
}
void remove(const Comparable &x)
{
remove(x,root);
}

const BinarySearchTree & operator= (const BinarySearchTree &rhs)
{
if(this != &rhs)
{
makeEmpty();
root = clone(rhs.root);
}
reuturn *this;
}

private:
struct BinaryNode
{
Comparable element;
BinaryNode *left;
BinaryNode *right;

BinaryNode(const Comparable & theElement,BinaryNode *lt,BinaryNode *rt)
:element(theElement),left(lt),right(rt){ }
};

BinaryNode *root;

void insert(const Comparable &x,BinaryNode *&t)const
{
if(t==NULL)
t = new BinaryNode(x,NULL,NULL);
else if(x<t->element)
insert(x,t->left);
else if(t->element<x)
insert(x,t->right);
else
;
}

void remove(const Comparable &x,BinaryNode *&t)const
{
if(t == NULL)
return;
if(x<t->element)
remove(x,t->left);
else if(t->element < x)
remove(x,t->right);
else if(t->left != NULL && t->right != NULL)
{
t->element = findMin(t->right)->element;
remove(t->element,t->right);
}
else
{
BinaryNode *oldNode = t;
t = (t->left != NULL) ? t->left:t->right;
delete oldNode;
}
}

BinaryNode * findMin(BinaryNode *t)const
{
if(t==NULL)
return NULL;
if(t->left ==NULL)
return t;
return findMin(t->left);
}

BinaryNode * findMax(BinaryNode *t)const
{
if(t != NULL)
while(t->right != NULL)
t = t->right;
return t;
}
bool contains(const Comparable &x,BinaryNode *t)const
{
if(t == NULL)
return false;
else if(x<t->element)
return contains(x,x->left);
else if(t->element<x)
return contains(x,t->right);
else
return true;
}
void makeEmpty(BinaryNode *&t)
{
if(t != NULL)
{
makeEmpty(t->left);
makeEmpty(t->right);
delete t;
}
t = NULL;
}
void printTree(BinaryNode *t)const
{
if(t != NULL)
{
//printf(t->element);
printTree(t->left);
printTree(t->right);
}
}
BinaryNode * clone(BinaryNode *t)const
{
if(t == NULL)
return NULL;
return new BinaryNode(t->element,clone(t->left),clone(t->right));
}
};