#include<iostream> # include<stdio.h> # include<malloc.h> typedef struct btnode { char data; struct btnode* left, *right; } btnode, *bitree; using namespace std; string s; int index = 0; void creat(bitree& bt) { if (s[index] == '#') { bt = NULL; index++; return ; } else { bt = (btnode*)malloc(sizeof(btnode)); bt->data = s[index++]; creat(bt->left); creat(bt->right); } } void in_order(bitree bt) { if (bt) { in_order(bt->left); printf("%c ", bt->data); in_order(bt->right); } } int main() { while (cin >> s) { bitree bt; creat(bt); in_order(bt); index = 0; } }