我正在为我的 compsci 类实现许多 LinkedList ADT，但我在每个类上都遇到了同样的问题。下面列出的代码是一个二叉树 ADT。尝试将数据输入新节点时，编译器会丢失。代码编译没有任何错误，但编译器没有返回任何东西，我认为它在尝试找到指针时卡住了。我来自 Java，所以我仍在研究指针。
#include <iostream>
struct TreeNode {
//represents a single node in a binary tree of int data
int data; //immediate data
TreeNode *left; //left subtree
TreeNode *right; //right subtree
TreeNode(int in);
};
TreeNode::TreeNode(int in) {
data = in;
left = NULL;
right = NULL;
}
编译器似乎无法找到这两个附加函数中引用的指针。
void addLeft(TreeNode *root, int newData) {
TreeNode *new_node;
new_node->data = newData;
root->left = new_node;
}
void addRight(TreeNode *root, int newData) {
TreeNode *new_node;
new_node->data = newData;
root->right = new_node;
}
//counts nodes in binary tree from designated root point
int countNodes(TreeNode *root) {
if (!root) {
return 0; //empty tree
}
int count = 1;
count += countNodes(root->left); //adds left subtree nodes
count += countNodes(root->right); //adds right subtree countNodes
return count;
}
void preorderPrint(TreeNode *root) { //root first, then left, then right
if (root) {
std::cout << root->data << " ";
preorderPrint(root->left);
preorderPrint(root->right);
}
}
void postorderPrint(TreeNode *root) { //left first, then right, then root
if (root) {
postorderPrint(root->left);
postorderPrint(root->right);
std::cout << root->data << " ";
}
}
void inorderPrint(TreeNode *root) { //left first, then root, then right
if (root) {
inorderPrint(root->left);
std::cout << root->data << " ";
inorderPrint(root->right);
}
}
bool tree_contains(TreeNode *root, int item) {
if (!root) {
return false; //if the root doesn't exist, the tree doesn't exist
}
else if (root->data = item) {
return true; //item is found in the root node
}
else if (root->data > item) {
}
}
int main() {
TreeNode *root;
root->data = 5;
addLeft(root, 4);
addRight(root,9);
inorderPrint(root);
return 0;
}
最佳答案
您的root 未初始化。它目前有一个未定义的值。应该是:
TreeNode *root = new TreeNode(5);
... // Do whatever you want
// delete root and everything else.
关于c++ - LinkedList ADT指针 block ，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/53455536/