I couldnt seem to resolve the unitialized local pointer "Parent". There isnt any other issue with this code other than the local pointer error I keep receiving Its driving me insane.
这只是我写的最简单的问题 请帮助我 我似乎无法解决单位化的本地指针＆＃34; Parent＆＃34;。除了我一直接受的本地指针错误之外，这个代码没有任何其他问题。它让我疯狂。
这只是我写的最简单的问题 请帮助我
//Binary Search Tree
#include <iostream>
#include <cstdlib>
using namespace std;
class BinarySearchTree
{
private:
struct tree_node
{
tree_node* left;
tree_node* right;
int data;
};
tree_node* root;
public:
BinarySearchTree()
{
root = NULL;
}
bool IsEmpty() const {
return root == NULL;
}
void print_inorder();
void inorder(tree_node*);
void print_preorder();
void preorder(tree_node*);
void print_postorder();
void postorder(tree_node*);
void insert(int);
void remove(int);
};
void BinarySearchTree::insert(int d)
{
tree_node* t = new tree_node;
tree_node* parent;
t->data = d;
t->left = NULL;
t->right = NULL;
parent = NULL;
if (IsEmpty()) root = t;
else
{
tree_node* curr;
curr = root;
while (curr)
{
parent = curr;
if (t->data > curr->data) curr = curr->right;
else curr = curr->left;
}
if (t->data < parent->data)
parent->left = t;
else
parent->right = t;
}
}
void BinarySearchTree::remove(int d)
{
tree_node* curr;
tree_node* parent;
bool found= false;
if (IsEmpty())
{
cout << " This Tree is Empty!" << endl;
return;
}
curr = root;
while (curr != NULL)
{
if (curr->data == d)
{
found = true;
break;
}
else {
parent = curr;
if (d > curr->data) curr = curr->right;
else curr = curr->left;
}
}
if (!found)
{
cout << " Data is not found!" << endl;
return;
}
if ((curr->left == NULL && curr->right != NULL) || (curr->left != NULL && curr->right == NULL))
{
if (curr->left == NULL && curr->right !=NULL)
{
if (parent -> left == curr)
{
parent->left = curr->right;
delete curr;
}
else {
parent->right = curr->right;
delete curr;
}
}
else //Left child
{
if (parent->left == curr)
{
parent->left = curr->left;
delete curr;
}
else
{
parent->right = curr->left;
delete curr;
}
}
return;
}
if (curr->left == NULL && curr->right == NULL)
{
if (parent->left == curr) parent->left = NULL;
else parent->right = NULL;
delete curr;
return;
}
//Node with 2 Children
if (curr->left != NULL && curr->right != NULL)
{
tree_node* chkr;
chkr = curr->right;
if ((chkr->left == NULL) && (chkr->right == NULL))
{
curr = chkr;
delete chkr;
curr->right = NULL;
}
else
{
if ((curr->right)->left != NULL)
{
tree_node* lcurr;
tree_node* lcurrp;
lcurrp = curr->right;
lcurr = (curr->right)->left;
while(lcurr ->left != NULL)
{
lcurrp = lcurr;
lcurr = lcurr->left;
}
curr->data = lcurr->data;
delete lcurr;
lcurrp->left = NULL;
}
else {
tree_node* tmp;
tmp = curr->right;
curr->data = tmp->data;
curr->right = tmp->right;
delete tmp;
}
}
return;
}
}
void BinarySearchTree::print_inorder()
{
inorder(root);
}
void BinarySearchTree::inorder(tree_node* p)
{
if (p != NULL)
{
if (p->left) inorder(p->left);
cout << " " << p->data << " ";
if (p->right) inorder(p->right);
}
else return;
}
void BinarySearchTree::print_preorder()
{
preorder(root);
}
void BinarySearchTree::preorder(tree_node* p)
{
if (p != NULL)
{
cout << " " << p->data << " ";
if (p->left)preorder(p->left);
if (p->right) preorder(p->right);
}
else return;
}
void BinarySearchTree::postorder(tree_node* p)
{
if (p != NULL)
{
if (p->left) postorder(p->left);
if (p->right) postorder(p->right);
cout << " " << p->data << " ";
}
else return;
}
int main()
{
BinarySearchTree b;
int ch, tmp, tmp1;
while (1)
{
cout << endl << endl;
cout << " Binary Search Tree Operations " << endl;
cout << "---------------------------------" << endl;
cout << " 1. Insertion/Creation " << endl;
cout << " 2. In-Order Traversal " << endl;
cout << " 3. Pre-Order Traversal " << endl;
cout << " 4. Post-Order Traversal " << endl;
cout << " 5. Removal " << endl;
cout << " 6. Exit " << endl;
cout << " Enter your choice: ";
cin >> ch;
switch (ch)
{
case 1: cout << "Enter Number to be Inserted: ";
cin >> tmp;
b.insert(tmp);
break;
case 2: cout << endl;
cout << " In-Order Traversal: " << endl;
cout << "---------------------" << endl;
b.print_inorder();
break;
case 3: cout << endl;
cout << " Pre-Order Traversal: " << endl;
cout << "------------------------" << endl;
b.print_preorder();
break;
case 4: cout << endl;
cout << " Post-Order Traversal: " << endl;
cout << "--------------------------" << endl;
b.print_postorder();
break;
case 5: cout << " Enter data to be deleted: ";
cin >> tmp1;
b.remove(tmp1);
break;
case 6: system("pause");
return 0;
break;
}
}
}
答案 0 :(得分：1)
tree_node* parent;
您声明父级但从不为其分配tree_node内存地址以指向。因此，对其执行操作或访问其成员（如parent->left）将导致问题，并引发您获得的错误。
解决方案：在访问其成员之前为父级分配值。