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

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

void insert(int value, BSTNode** a_root) {
    if(*a_root == NULL) {  // If the tree is empty...
        // Create a tree of size 1
        BSTNode* new_node = malloc(sizeof(*new_node));
        *new_node = (BSTNode) { .value = value, .left = NULL, .right = NULL };

        // Replace root with our newly created tree of size 1
        *a_root = new_node;  // fine for tree of size 1
    }
    else if(value < (*a_root) -> value) {  // If value is < value at the root
        // Insert the value into the left subtree of root.
        // BSTNode* left_subtree = (*a_root) -> left;  // BUG!!!
        // insert(value, &left_subtree);               // BUG!!!

        insert(value, &( (*a_root) -> left) );  // need to modify field within struct object
        //            │  └────────────────┘ │
        //            │     .left field     │
        //            │    (left subtree)   │
        //            │                     │
        //            └─────────────────────┘
        //             address of .left field
    }
    else {  // If value is ≥ value at the root
        // Insert the value into the right subtree of root.
        // BSTNode* right_subtree = (*a_root) -> right;  // BUG!!!
        // insert(value, &right_subtree);                // BUG!!!

        insert(value, &((*a_root) -> right));  // need to modify field within struct object
    }
}

int main(int argc, char* argv[]) {
    // size == 0  (empty tree)
    BSTNode* root = NULL;

    insert(4, &root);
    insert(2, &root);
    insert(1, &root);
    insert(3, &root);
    insert(6, &root);
    insert(5, &root);
    insert(7, &root);
    assert(root -> value == 4);
    assert(root -> left  -> value == 2);
    assert(root -> left  -> left  -> value == 1);
    assert(root -> left  -> right -> value == 3);
    assert(root -> right -> value == 6);
    assert(root -> right -> left  -> value == 5);
    assert(root -> right -> right -> value == 7);
    assert(root -> right -> right -> left  == NULL);
    assert(root -> right -> right -> right == NULL);
    assert(root -> right -> left  -> left  == NULL);
    assert(root -> right -> left  -> right == NULL);
    assert(root -> left  -> right -> left  == NULL);
    assert(root -> left  -> right -> right == NULL);
    assert(root -> left  -> left  -> left  == NULL);
    assert(root -> left  -> left  -> right == NULL);
    
    // TODO:  Free the BST
    return EXIT_SUCCESS;
}
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