用C语言编写一个能运行的中序遍历二叉树T的非递归算法

好的，下面是用C语言编写的中序遍历二叉树的非递归算法：

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

struct TreeNode {
    int val;
    struct TreeNode* left;
    struct TreeNode* right;
};

void inorderTraversal(struct TreeNode* root) {
    struct TreeNode* stack[1000];
    int top = -1;
    struct TreeNode* node = root;
    while (node || top != -1) {
        while (node) {
            stack[++top] = node;
            node = node->left;
        }
        node = stack[top--];
        printf("%d ", node->val);
        node = node->right;
    }
}

int main() {
    // 构造测试用例
    struct TreeNode* root = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->val = 1;
    root->left = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->left->val = 2;
    root->left->left = NULL;
    root->left->right = NULL;
    root->right = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->right->val = 3;
    root->right->left = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->right->left->val = 4;
    root->right->left->left = NULL;
    root->right->left->right = NULL;
    root->right->right = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->right->right->val = 5;
    root->right->right->left = NULL;
    root->right->right->right = NULL;

    // 中序遍历
    inorderTraversal(root);

    return 0;
}

其中，stack数组是用来存储待访问的节点的，top是栈顶指针，node是当前访问的节点。算法的思路是，先把当前节点的所有左子树节点入栈，然后访问栈顶节点并出栈，最后访问栈顶节点的右子树。重复这个过程直到栈为空。