二叉树中序遍历代码c语言

以下是二叉树中序遍历的C语言代码，其中包括递归和迭代两种实现方式：

1. 递归实现：

void inorderTraversal(struct TreeNode* root, int* returnSize, int* res) {
    if (root == NULL) {
        return;
    }
    inorderTraversal(root->left, returnSize, res);
    res[(*returnSize)++] = root->val;
    inorderTraversal(root->right, returnSize, res);
}

2. 迭代实现：

int* inorderTraversal(struct TreeNode* root, int* returnSize) {
    int* res = (int*)malloc(sizeof(int) * 100);
    *returnSize = 0;
    struct TreeNode* stack[100];
    int top = -1;
    while (root != NULL || top != -1) {
        while (root != NULL) {
            stack[++top] = root;
            root = root->left;
        }
        if (top != -1) {
            root = stack[top--];
            res[(*returnSize)++] = root->val;
            root = root->right;
        }
    }
    return res;
}