0

全部！

我正在尝试开发一个制作二叉树预线程然后打印它的函数，但我遇到了一些麻烦。代码已编译，但是当我运行程序时它崩溃了。您可以在下面找到我的代码。

#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;
#define MaxNodeNum 50
class ThreadTree;
istream& operator>>(istream& in,ThreadTree& Tree);
struct ThreadNode{`int ltag,rtag;           
ThreadNode *leftChild,*rightChild;      
char data;                              
ThreadNode():data(NULL),leftChild(NULL),
    rightChild(NULL),ltag(0),rtag(0){}
ThreadNode(const char item):data(item),leftChild(NULL),
    rightChild(NULL),ltag(0),rtag(0){}

};

class ThreadTree{`protected:
ThreadNode *root;         
char *element;            
int CurNodeNum;           
void CreateBinTree(ThreadNode*& subTree);
friend istream& operator>>(istream& in,ThreadTree& Tree);
void createPreThread(ThreadNode *current,ThreadNode *& pre);    
void destroy(ThreadNode *&subTree);
public:
ThreadTree():root(NULL){}
void createPreThread();   
ThreadNode *Root()
{   return root;    }
void ConstructTree(char A[],int n,int i,ThreadNode *& ptr);
ThreadNode *First(ThreadNode *current);    
ThreadNode *Next(ThreadNode *current);     
void PreOrder();                           
~ThreadTree(){  destroy(root);  }

};

void ThreadTree::CreateBinTree(ThreadNode*& subTree){          
char s[MaxNodeNum];
cout<<"Input the nodes，'#'represents null nodes，the number of nodes<="<<MaxNodeNum<<endl;
cin>>s;
CurNodeNum=strlen(s);
element=new char[CurNodeNum];
for(int i=0;i<CurNodeNum;i++)
    element[i]=s[i];

}

void ThreadTree::ConstructTree(char A[],int n,int i,ThreadNode *& ptr){   
if(i>=n)    ptr=NULL;                                                  
else{
    if(A[i]!='#'){
        ptr=new ThreadNode(A[i]);
        ConstructTree(A,n,2*i+1,ptr->leftChild);
        ConstructTree(A,n,2*i+2,ptr->rightChild);
    }
    else    i++;
}

}

istream& operator>>(istream& in,ThreadTree& Tree){
Tree.CreateBinTree(Tree.root);
Tree.ConstructTree(Tree.element,Tree.CurNodeNum,0,Tree.root);
return in;

}

void ThreadTree::createPreThread(){                             
ThreadNode *pre=NULL;
if(root!=NULL){
    createPreThread(root,pre);
    pre->rightChild=NULL;   pre->rtag=1;
}

}

void ThreadTree::createPreThread(ThreadNode *current,ThreadNode *& pre){     
if(current==NULL)   return;
if(current->leftChild==NULL){
    current->leftChild=pre;
    current->ltag=1;
}
if(pre!=NULL && pre->rightChild==NULL){
    pre->rightChild=current;
    pre->rtag=1;
}
pre=current;
createPreThread(current->leftChild,pre);
createPreThread(current->rightChild,pre);

}

ThreadNode* ThreadTree::First(ThreadNode *current){
return current;

}

ThreadNode * ThreadTree::Next(ThreadNode *current){
if(current->ltag==1){
    if(current->rightChild==NULL)
        return NULL;
    else
        return current->rightChild;
}else
    return current->leftChild;

}

void ThreadTree::PreOrder(){      
ThreadNode *q;
for(q=First(root);q!=NULL;q=Next(q))
    cout<<q->data<<"  ";

}

void ThreadTree::destroy(ThreadNode *&subTree){
if(subTree!=NULL){
    destroy(subTree->leftChild);
    destroy(subTree->rightChild);
    delete subTree;
}

}

int main(){
ThreadTree tree;
cin>>tree;
tree.createPreThread();
cout<<tree.Next(tree.Root())->data;
cout<<endl;
tree.PreOrder();
return 0;

}

请帮助我。提前致谢！

4

0 回答 0