对上面前序遍历和中序遍历树输出层次遍历的的修改

#include <iostream>

#include <stdio.h>
#include <queue>
using namespace std;
struct node{
int data;
node* lchild;
node* rchild; 
};
const int maxn=100;
int pre[maxn],in[maxn];
int n;
node* create(int prel,int prer,int inl,int inr){
if(prel>prer)  return NULL;
node* root=new node;
root->data=pre[prel];
int k;
for(int i=inl;i<=inr;i++){
if(pre[prel]==in[i]){
k=i;
break;
}
}
int numleft=k-inl;
root->lchild=create(prel+1,prel+numleft,inl,k-1);
root->rchild=create(prel+numleft+1,prer,k+1,inr); 
return root;
}
int num=0;
void bfs(node* root){
queue<node*> Q;
// if(root==NULL)  return ;
  while(!Q.empty())  Q.pop();
Q.push(root); 
while(!Q.empty()){
node* now = Q.front(); 
printf("%d",now->data);
if(num<n) printf(" ");
num++;
Q.pop();
if(now->lchild!=NULL) Q.push(now->lchild);
if(now->rchild!=NULL) Q.push(now->rchild);
}
} 
int main(int argc, char** argv) {
scanf("%d",&n);
for(int i=0;i<n;i++){
scanf("%d",&pre[i]);
}
for(int i=0;i<n;i++){
scanf("%d",&in[i]);
}
node* root=create(0,n-1,0,n-1);
bfs(root);
return 0;

}

//指正定义完要初始化；