创建一个数组，其中包含一个级别的节点值

I have to create an array that contains the values of nodes in a level passed as parameter. The function createArray has to return an array containing the values of the nodes at the level passed as parameter. My code is:

我必须创建一个数组，其中包含作为参数传递的级别中的节点值。函数createArray必须返回一个数组，该数组包含作为参数传递的级别的节点值。我的代码是：

#include "stdafx.h"
#include <cstdlib>
#include <iostream>
#include <stdlib.h>
#include <stdio.h>

struct node {
    int data;
    struct node* left;
    struct node* right;
};

struct node* newNode(int data) {
    struct node* node = (struct node*)malloc(sizeof(struct node));
    node->data = data;
    node->left = NULL;
    node->right = NULL;

    return node;
}

int numNodesLevel(struct node* root, int level) {
    if (root == NULL) {
        return 0;
    }
    else {
        if (level == 0) {
            return 1;
        }
        return numNodesLevel(root->left, level - 1) + numNodesLevel(root->right, level - 1);
    }
}

int max(int a, int b) {
    if(a > b) {
        return a;
    }
    else {
        return b;
    }
}

int height(struct node* root) {
    if (root == NULL) {
        return -1;
    }
    else {
        if (root->left == NULL && root->right == NULL) {
            return 0;
        }
        return max(height(root->left), height(root->right)) + 1;
    }
}

int maxNodesLevel(struct node* root) {
    if (root == NULL) {
        return 0;
    }
    else {
        int max = 0;
        int h = height(root);
        int i = 0;
        for (i = 0; i <= h; i++) {
            if (numNodesLevel(root, i) > max) {
                max = numNodesLevel(root, i);
            }
        }
        return max;
    }
}

void fill(struct node* root, int* A, int level, int* i) {
    if (root != NULL) {
        if (level == 0) {
            A[*i] = root->data;
            *i = *i + 1;
        }
        fill(root->left, A, level - 1, i);
        fill(root->right, A, level - 1, i);
    }
}

int* createArray(struct node* root, int level) {
    if (root != NULL) {
        int *A = (int*)calloc(maxNodesLevel(root), sizeof(int));
        int i = 0;
        fill(root, A, level, &i);
        return A;
    }
}

int main(){
    struct node* root = newNode(12);
    root->left = newNode(3);
    root->right = newNode(16);
    root->left->left = newNode(2);
    root->left->right = newNode(2);
    root->right->left = newNode(2);
    root->right->right = newNode(22);
    printf("%d", createArray(root,1));
    getchar();
    return 0;
}

The result should be 3,16 which are the values of the nodes at level 1, but it gives me different numbers like 22721648. These numbers are different every time I run the code, so I think there must be something wrong in the way I use pointers, but I can't figure out where is the error. Can somebody help me?

结果应该是3,16，这是1级节点的值，但它给了我不同的数字，如22721648.每次运行代码时这些数字都不同，所以我觉得我的方式一定有问题使用指针，但我无法弄清楚错误在哪里。有人能帮助我吗？

1 个解决方案

#1

The code is correct, but only mistake here is createArray() returns an array and you are considering it as int. Add following code instead of printf() and it will work.

代码是正确的，但这里唯一的错误是createArray（）返回一个数组，你将它视为int。添加以下代码而不是printf（），它将起作用。

int level = 1, *arr;
arr = createArray(root, level);
for(int i = 0; i < 2 * level; i++){
    printf("%d ", arr[i]);
}

Hope it will help !!

希望它会有所帮助!!

#1