Establishing and traversing binary tree

  Define the pre order sequence of a binary tree in the form of string , If the character is ‘#’, Indicates that the binary tree is empty , Otherwise, the character is the data element of the corresponding node . Read in the corresponding sequence , establish Binary storage structure Two fork tree , Then traverse the binary tree in middle order and output node data .

sample input :

Here's a set of inputs . for example ：

ABC##DE#G##F###

sample output :

Here is the corresponding output . for example ：

CBEGDFA

#include "bits/stdc++.h"

using namespace std;

struct Tree{
    char val;
    Tree* lchild;
    Tree* rchild;
};
Tree* build(){
    char c;
    cin >> c;
    if(c=='#') return NULL;
    Tree* root = new Tree();
    root->val = c;
    root->lchild = build();
    root->rchild = build();
    return root;
}
void dfs(Tree* root){
    if(root == NULL) return;
    dfs(root->lchild);
    cout << root->val ;
    dfs(root->rchild);
}
int main()
{
    Tree* root = build();
    dfs(root);
    return 0;
}