以下问题是关于二叉树的，情况如下~

Question

输入：abd??e?g??cf???#include "iostream"using namespace std;struct Node{char data;Node*Lchild;Node*Rchild;};class tree{public:tree();Node*Createtree(Node*T);void InorderTraverse(Node*T);void bianli(int i);private:Node*head;};tree::tree(){head=Createtree(head);cout<<head->data<<" "<<(head->Lchild)->data;//调试到这里根节点的左右子树没有相应的值}Node*tree::Createtree(Node*T){char ch;cin>>ch;if(ch=='?'){T=NULL;}else{T=new Node;T->data=ch;Createtree(T->Lchild);Createtree(T->Rchild);return T;}}void tree::InorderTraverse(Node*T){if(T!=NULL){InorderTraverse(T->Lchild);cout<<T->data<<" ";InorderTraverse(T->Rchild);}}void tree::bianli(int i){if(i==1)InorderTraverse(head);}int main(){tree a;a.bianli(1);}

Answer 1

Node*tree::Createtree()
{ Node * T=NULL；
char ch;
cin>>ch;
if(ch=='?') return NULL;

T=new Node;
T->data=ch;
T->Lchild
=Createtree();
T->Rchild
=Createtree();
return T;
}

Answer 2

Createtree函数中ch == '?'处没有返回值？