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

typedef struct _BSTNode {
    struct _BSTNode* left;
    struct _BSTNode* right;
    int value;
} BSTNode;

// if you include level and side for a pre-order print,
// can be good for debugging your tree strucutre
void print_pre_order(BSTNode* root, int level, char side) {
    if (root != NULL) {
        for (int i = 0; i < level; i++) {
            fputc(' ', stdout);
        }
        printf("%c: %d\n", side, root->value);
        print_pre_order(root->left, level + 1, 'L');
        print_pre_order(root->right, level + 1, 'R');
    }
}

// best for printing the full sorted tree, or transferring it to
// an array
void print_in_order(BSTNode* root) {
    if (root != NULL) {
        print_in_order(root->left);
        printf("%d\n", root->value);
        print_in_order(root->right);
    }
}

// freeing the tree uses a post order traversal
void destroy_bst(BSTNode* root) {
    if (root != NULL) {
        destroy_bst(root->left);
        destroy_bst(root->right);
        free(root);
    }
}

BSTNode* bst_insert(BSTNode* root, int value) {
    if (root == NULL) {
        BSTNode* new_node = malloc(sizeof(*new_node));
        *new_node = (BSTNode) {
            .value = value,
            .left = NULL,
            .right = NULL
        };
        return new_node;
    } else if (value < root->value) {
        root->left = bst_insert(root->left, value);
        return root;
    } else {
        root->right = bst_insert(root->right, value);
        return root;
    }
}


int main(int argc, char* argv[]) {
    BSTNode* root = NULL;

    root = bst_insert(root, 5);
    root = bst_insert(root, 8);
    root = bst_insert(root, 3);
    root = bst_insert(root, 1);
    root = bst_insert(root, 4);
    root = bst_insert(root, 9);
    root = bst_insert(root, 2);


    printf("Pre order:\n");
    print_pre_order(root, 0, 'R');
    printf("In order:\n");
    print_in_order(root);

    destroy_bst(root);

    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */

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