I’m in the middle of building an AVL Tree until this odd thing happened. When i comment this printf() on line 81, my resulting balance factor shows random(?) number when it’s actual BF is 0. But, when i uncomment the printf() line, the resulting BF shows 0. How is this happening?

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

struct data {
    
    int num;
    struct data *left;
    struct data *right;
    int bf;
    
};

struct data *root = NULL;

struct data *create_node(int num){
    
    struct data *new_node = (struct data*)malloc(sizeof(struct data));
    new_node->num = num;
    new_node->left = NULL;
    new_node->right = NULL;
    
    return new_node;
    
}

int bf_left(struct data *bot, int depth){
    
    if(bot == NULL){
        return depth - 1;
    }
    int temp = bf_left(bot->left, depth + 1);
    int temp2 = bf_left(bot->right, depth + 1);
    
    if(temp > temp2){
        return temp;
    } else if(temp <= temp2){
        return temp2;
    }
    
}

int bf_right(struct data *bot, int depth){
    
    if(bot == NULL){
        return depth - 1;
    }
    int temp = bf_right(bot->left, depth + 1);
    int temp2 = bf_right(bot->right, depth + 1);
    
    if(temp > temp2){
        return temp;
    } else if(temp <= temp2){
        return temp2;
    }
    
}

int bf_finder(struct data *bot){
    
    int left = bf_left(bot->left, 1);
    int right = bf_right(bot->right, 1);
    return left - right;
    
}

struct data *insert(struct data *bot, int num){
    
    if(bot == NULL){
        if(root == NULL){
            root = create_node(num);
            bot = root;
        } else{
            return create_node(num);
        }
    } else if(num < bot->num){
        bot->left = insert(bot->left, num);
    } else if(num > bot->num){
        bot->right = insert(bot->right, num);
    }
    
//  printf("%dn", bot->num);
    bot->bf = bf_finder(bot);
    
}

void print_all(struct data *bot){
    
    if(bot != NULL){
        print_all(bot->left);
        printf("%d. bf: %dn", bot->num, bot->bf);
        print_all(bot->right);
    }
    
}

int main(){
    
    insert(root, 10);
    insert(root, 9);
    insert(root, 11);
    insert(root, 12);
    
    print_all(root);
    
    return 0;
    
}

I’m expecting for my code to show an actual BF of 0 if it’s actually 0 with or without this printf() line because i thought there’s no way a single printf() can affect this much but if i’m wrong, i wanna know what is actually happening.