二叉树遍历、计算叶节点、计算深度（递归）

#include<bits/stdc++.h>
using namespace std;
typedef struct node{
    
    
	char data;
	struct node *lchild,*rchild;
}*BiTree;
int len=0;
string s;
//字符串方式输入先序建立二叉树 
void CreateTree(BiTree &T)
{
    
    
	if(len==s.size()) return;
	char c=s[len++];
	if(c=='#') T=NULL;//#表示节点为空 
	else
	{
    
    
		T=new node;
		T->data=c;
		T->lchild=T->rchild=NULL;
		CreateTree(T->lchild);
		CreateTree(T->rchild);
	}
}
//字符输入方式先序遍历建立二叉树 
createTree(BiTree &T)
{
    
    
	char c;
	cin>>c;
	if(c=='0') T=NULL;//0表示节点为空 
	else
	{
    
    
		T=new node;
		T->data=c;
		T->lchild=T->rchild=NULL;
		createTree(T->lchild);
		createTree(T->rchild);
	}
} 
void Preorder(BiTree T)
{
    
    
	if(T!=NULL)
	{
    
    
		cout<<T->data<<" ";
		Preorder(T->lchild);
		Preorder(T->rchild); 
	} 
 } 
 void Inorder(BiTree T)
{
    
    
	if(T!=NULL)
	{
    
    
		Inorder(T->lchild);
		cout<<T->data<<" ";		
		Inorder(T->rchild); 
	} 
 } 
  void Postorder(BiTree T)
{
    
    
	if(T!=NULL)
	{
    
    
		Postorder(T->lchild);
		Postorder(T->rchild); 
		cout<<T->data<<" ";	
	} 
 }
 //二叉树叶节点 
int leaf_number(BiTree T)
{
    
    
	if(T==NULL) return 0;
	if(T->lchild==NULL&&T->rchild==NULL) return 1;
	return leaf_number(T->lchild)+leaf_number(T->rchild);
}
//二叉树深度
int depth(BiTree T)
{
    
    
	if(T==NULL) return 0;
	int x=depth(T->lchild);
	int y=depth(T->rchild);
	return max(x,y)+1;
 } 
int main()
{
    
    
	BiTree T;
    len=0;
	createTree(T);	
	Preorder(T);
	cout<<endl;
	Inorder(T);
	cout<<endl;
	Postorder(T);
	cout<<endl;
	int leaf=leaf_number(T);
	cout<<leaf<<endl;	
	return 0;
}