Binary Tree Inorder Traversal

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* inorderTraversal(struct TreeNode* root, int* returnSize){
*returnSize = 0;

    // Check if the root is NULL
    if (root == NULL) {
        return NULL;
    }

    // Create an array to store the result (assuming a maximum of 100 nodes)
    int* result = (int*)malloc(100 * sizeof(int));

    // Initialize the index to 0
    int index = 0;

    struct TreeNode* stack[100]; // Stack to perform iterative traversal
    int top = -1;

    struct TreeNode* current = root;

    while (current != NULL || top != -1) {
        while (current != NULL) {
            // Push the current node onto the stack
            stack[++top] = current;
            current = current->left;
        }

        // Process the current node
        current = stack[top--];
        result[index++] = current->val;

        // Move to the right subtree
        current = current->right;
    }

    // Update the returnSize to the actual size of the result array
    *returnSize = index;

    // Return the result array
    return result;
}