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;
}