在二叉树中查找值为x的结点，试编写算法（用c语言）打印值为x的节点的所有祖先，假设值为x的结点不多于1个

#include <iostream>
#include <stack>
#include<queue>
typedef struct treenode{
    char data;
    struct treenode *left;
    struct treenode *right;
}treenode,*ptreenode;

ptreenode buytreenode(char x)
{
    ptreenode n=(ptreenode) malloc(sizeof (treenode));
    n->data=x;
    n->left= nullptr,n->right= nullptr;
    return n;
}
ptreenode build_tree()
{
    ptreenode root= buytreenode('A');
    root->left= buytreenode('B');
    root->right= buytreenode('C');
    root->left->left= buytreenode('D');
    root->left->right= buytreenode('E');
    root->right->left= buytreenode('F');
    root->right->right= buytreenode('G');
    root->left->left->left= buytreenode('H');
    root->left->left->right= buytreenode('I');
    return root;
}


void print_tree(ptreenode root) {
    std::queue<ptreenode> tmp;
    tmp.push(root);
    int s = tmp.size();
    while (!tmp.empty()) {
        ptreenode t = tmp.front();
        tmp.pop();
        s--;
        printf("%3c", t->data);
        if (t->left) tmp.push(t->left);
        if (t->right) tmp.push(t->right);
        if (s == 0) puts(""), s = tmp.size();
    }
}
void path(ptreenode root,char x)
{
    ptreenode pre= nullptr,pointer=root;
    std::stack<ptreenode> tmp;
    while(pointer||!tmp.empty())
    {
        while(pointer) tmp.push(pointer),pointer=pointer->left;
        pointer=tmp.top();
        if(pointer->data==x){
            while(!tmp.empty()){
                printf("%3c",tmp.top()->data);
                tmp.pop();
            }
            return;
        }
        if(pointer->left&&pointer->right!=pre){
            pointer=pointer->right;
        }else{
            tmp.pop();
            pre=pointer;
            pointer= nullptr;
        }
    }
}
int main() {
    ptreenode root=build_tree();
    print_tree(root);
    puts("");
    path(root,'H');

    puts("");
    path(root,'I');

    puts("");
    path(root,'B');

    puts("");
    path(root,'F');

    puts("");
    path(root,'G');
    return 0;
}