Дерево .Помощь в исправлении ошибок

#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//Êëàññ äåðåâà
class Tree
{int info;
Tree *left,*right;
public:
Tree *root;
Tree() {root=NULL;}
void stree(Tree *r,Tree*prev,int info);
Tree *dtree(Tree*r,int key);
void preorder (Tree *r,TLabel *tl);
void inorder(Tree *r,TLabel *tl);
void postorder(Tree *r, TLabel *tl);
Tree *SearchTree(Tree*r,int key);
void PrintTree(Tree *r,int l,TMemo *tm);
 
}
//Ïðîõîæäåíèå äåðåâà
 void Tree::inorder(Tree*r,TLabel*tl)
 {
 if(!r) return;
  inorder(r->left);
  if(r->info)
  tl->Caption=tl->Caption+InToStr(r->info)+ " " ;
  inorder (r->right,tl);
 }
 void Tree::preorder(Tree*r,TLabel*tl)
 {if(!r) return;
  if(r->info)
  tl->Caption=tl->Caption+InToStr(r->info)+ " " ;
  preorder (r->right,tl);
 }
  void Tree::postorder(Tree*r,TLabel*tl)
 {if(!r) return;
  postorder(r->left,tl);
  postorder(r->right,tl);
  tl->Caption=tl->Caption+InToStr(r->info)+ " " ;
 }
 //Äîáàâëåíèå íîâîãî ýëåìåíòà
 void Tree::stree(Tree*r,Tree*prev,int info)
 {if(!r)
 {r=new Tree;
 if (!r)exit(1);//íå óäàëîñü ñîçäàòü
 r->left=NULL;
 r->right=NULL;
 r->info=info;
 if(!root)
 root=r;
 else
 {if (info<prev->info)prev->left=r;
 else prev->right=r;
 }
 return;
 }
 if(info<r->info) stree(r->left,r,info);
 else stree (r->right,r,info);
 }
 //Ïîèñê ïî äåðåâó
Tree *Tree::SearchTree(Tree *r,int key)
{if(!r)return r;
while (r->info!=key)
{if (key<r->info) r=r->left;
else r=r->right;
if(r=NULL) break;
}
return r;
}
//Óäàëåíèå ýëåìåíòà èç äåðåâà
Tree*Tree::dtree (Tree *r,int key)
{Tree *p,*p2;
if(!r)return r;
if(r->info==key)
{if(r->left==r->right)
{free(r);
if(r==root)root=NULL;
return NULL;
}
else if(r->left==NULL)
{p=r->right;
 free(r);
 if(r==root)root=r;
 return p;
}
else if(r->right==NULL)
{p=r->left;
free(r);
if(r==root) root=p;
return p;
}
else
{
p2=r->right;
p=r->right;
while (p->left)
p=p->left;
p->left=r->left;
free(r);
if(r==root)
root=p2;
return p2;
}
}
if(r->info<key)
r->right=dtree(r->right,key);
else
r->left=dtree(r->left,key);
return r;
}
//îòîáðàæåíèå äåðåâà
void Tree::PrintTree(Tree*r,int l,TMemo*tm)
{AnsiString s;
int i;
if(!r) return;
PrintTree(r->right,int l+1);
for(i=0;i<l;i++)
s+=" ";
s+=AnsiString(r->info);
tm->Lines->Add(s);
PrintTree(r->left,l+1);
}
Tree it;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
Memo1->Clear();
int s;
s=Edit1->Text.ToInt();
it.stree(it.root,NULL,s);
it.PrintTree(it.root,0);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
Memo1->Clear();
int s;
s=Edit1->Text.ToInt();
it.dtree(it.root,s);
it.PrintTree(it.root,0);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button3Click(TObject *Sender)
{
Label1->Caption=" ";
Label2->Caption=" ";
Label3->Caption=" ";
it.inorder(it.root,Label1);
it.preorder(it.root,Label2);
it.postorder(it.root,Label3);
}
//---------------------------------------------------------------------------