给我用c++编写一个二叉树先序非递归遍历实例

可以参考以下代码：

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

#define MAX_SIZE 50

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

typedef struct Stack {
    TreeNode* data[MAX_SIZE];
    int top;
} Stack;

TreeNode* createNode(int val) {
    TreeNode* node = (TreeNode*)malloc(sizeof(TreeNode));
    node->val = val;
    node->left = NULL;
    node->right = NULL;
    return node;
}

void push(Stack* s, TreeNode* node) {
    if (s->top == MAX_SIZE-1) {
        printf("Stack overflow.\n");
        return;
    }
    s->data[++s->top] = node;
}

TreeNode* pop(Stack* s) {
    if (s->top == -1) {
        return NULL;
    }
    return s->data[s->top--];
}

void preorderTraversal(TreeNode* root) {
    if (root == NULL) {
        return;
    }
    Stack s;
    s.top = -1;
    push(&s, root);
    while (s.top != -1) {
        TreeNode* node = pop(&s);
        printf("%d ", node->val);
        if (node->right != NULL) {
            push(&s, node->right);
        }
        if (node->left != NULL) {
            push(&s, node->left);
        }
    }
}

int main() {
    TreeNode* root = createNode(1);
    root->left = createNode(2);
    root->right = createNode(3);
    root->left->left = createNode(4);
    root->left->right = createNode(5);
    root->right->left = createNode(6);
    root->right->right = createNode(7);
    printf("Preorder traversal of the binary tree: ");
    preorderTraversal(root);
    printf("\n");
    return 0;
}

输出结果为：

Preorder traversal of the binary tree: 1 2 4 5 3 6 7

请问还有什么我可以帮您解答的吗？