在非空二叉排序树中求出指定关键字的结点的层次C语言完整代码mian函数简单点

以下是求出指定关键字的结点的层次的 C 语言完整代码，其中 `main` 函数部分更简单：

#include <stdio.h>
#include <stdlib.h>

struct TreeNode {
    int key;
    struct TreeNode *left;
    struct TreeNode *right;
};

int find_node_level(struct TreeNode *root, int key) {
    /*
     * 在非空二叉排序树中查找指定关键字的结点，并返回其层次
     */
    int level = 1;
    struct TreeNode *node = root;
    while (node != NULL) {
        if (node->key == key) {
            return level;
        }
        else if (node->key < key) {
            node = node->right;
        }
        else {
            node = node->left;
        }
        level++;
    }
    // 没有找到指定结点，返回 -1
    return -1;
}

int main() {
    // 创建二叉排序树
    struct TreeNode *root = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->key = 5;
    root->left = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->left->key = 3;
    root->left->left = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->left->left->key = 1;
    root->left->left->left = NULL;
    root->left->left->right = NULL;
    root->left->right = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->left->right->key = 4;
    root->left->right->left = NULL;
    root->left->right->right = NULL;
    root->right = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->right->key = 7;
    root->right->left = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->right->left->key = 6;
    root->right->left->left = NULL;
    root->right->left->right = NULL;
    root->right->right = (struct TreeNode *) malloc(sizeof(struct TreeNode));
    root->right->right->key = 8;
    root->right->right->left = NULL;
    root->right->right->right = NULL;

    // 查找指定结点的层次
    int key = 4;
    int level = find_node_level(root, key);
    if (level == -1) {
        printf("The node with key %d is not found.\n", key);
    }
    else {
        printf("The level of the node with key %d is: %d\n", key, level);
    }

    return 0;
}

在此示例代码中，我们创建了一个二叉排序树，并查找了关键字为 4 的结点的层次。如果找到了指定结点，则输出其层次；否则，输出未找到指定结点的提示信息。