Convert a binary tree to a Complete Binary Tree

The meaning is to convert a common binary tree into a Complete Binary Tree. The binary tree is stored by link, and the Complete Binary Tree is stored in sequence. The idea is to allocate space to the null node and assign its data field to '#'; the pointer field is null. Sequence traversal of this binary tree

Reference code:

#include<iostream>using namespace std;struct BiNode{char data;BiNode *lchild,*rchild;};char a[200];int flag,len,k;class BiTree{private:BiNode* root;BiNode* Creat(BiNode *bt){char ch;cin>>ch;if(ch=='#'){bt=NULL;}else{len++;flag=1;bt=new BiNode;bt->data=ch;bt->lchild=Creat(bt->lchild);bt->rchild=Creat(bt->rchild);}return bt;}void Release(BiNode *bt){if(bt!=NULL){Release(bt->lchild);Release(bt->rchild);delete bt;}}public:BiTree(){root=Creat(root);}void LeverOrder(){int front,rear;front=rear=-1;BiNode *S[100],*q;if(root==NULL)return;S[++rear]=root;while(front!=rear){q=S[++front];cout<<q->data;if(q->data!='#')k++;if(len==k)break;if(q->lchild!=NULL)S[++rear]=q->lchild;else{BiNode *r=new BiNode;r->data='#';r->lchild=NULL;r->rchild=NULL;S[++rear]=r;}if(q->rchild!=NULL)S[++rear]=q->rchild;else{BiNode *t=new BiNode;t->data='#';t->lchild=NULL;t->rchild=NULL;S[++rear]=t;}}cout<<endl;}~BiTree(){Release(root);}};int main(){int T;cin>>T;while(T--){flag=len=k=0;BiTree A;if(flag==0){cout<<'#'<<endl;continue;}A.LeverOrder();}return 0;}