create an array with the values of the nodes at a level

Question

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:

#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?

Answer 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.

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

Hope it will help !!