Delete from binary tree

agoswami (135)
Hi,
I was trying to hands on binary tree. I was able to successfully create and print the binary.But when I trying to delete node than it is going to infinite loop.
I could not resolve this issue. any input into below program.



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/* Height of tree :Number of element */
#include<iostream>
using namespace std;

class node
{
   public:
   int data;
   node *left;
   node *right;
};

class tree
{
  public:
  node *root;
  tree();
  void create_tree(int data);
  void print_path(node *root);
  int height_tree(node *root);
  void delete_tree(int data);
};

tree::tree()
{
  root=NULL;
}

void tree::create_tree(int data)
{
        cout<<"create"<<endl;
	node *temp = new node;
	temp->data = data;
	temp->left =NULL;
	temp->right =NULL;

        if(root==NULL)
	    root=temp;
        else
	{
	   node *p=root;
           node *trail =NULL;
           while(p!=NULL)
	   {
	      trail=p;
              if(p->data > data)
	           p=p->left;
              else
		   p=p->right;
	   }

	   if(trail->data > data)
		   trail->left = temp;
	   else
		   trail->right = temp;
	}
}

void tree::print_path(node *root)
{
	if(root!=NULL)
	{
	 print_path(root->left);
	 cout<<root->data<<"    ";
	 print_path(root->right);
        }
}

int tree::height_tree(node *root)
{
	if(root==NULL)
		return 0;
	else
	 return(height_tree(root->left)+1+height_tree(root->right));
}

void tree::delete_tree(int data)
{ 
	node *p=root;
        node *trail =NULL;   
	while(p!=NULL)
	{
           trail=p;		
	   if(p->data > data)
		   p=p->left;
	   else if(p->data < data)
		   p=p->right;
	   else if(p->data == data)
		{
		    cout<<"data match";	
	            break;
		 }
          else
	  {
              cout<<"data did not find";
	      break;
	  }
	}
        if(trail->left ==NULL)
	 {
            node *temp=trail;
            trail=trail->right;
            delete temp;	    
	 }
	else if(trail->right ==NULL)
	 {
	   node *temp =trail;
	   trail=trail->left;
	   delete temp;
	 }
         
        else 
	{
	   if(trail->left !=NULL && trail->right !=NULL)
	   {
	      node *temp = trail->right;
	      cout<<temp->data<<endl;

	      while(temp->left!=NULL)
		      temp=temp->left;
	      
	      temp->left = trail->left;
	      temp=trail;
	      
	      trail=trail->right;
	      cout<<temp->data<<endl;
	      cout<<trail->data<<endl;
	      delete temp;
	   }
         }
}

int main()
{
    tree t;
    t.create_tree(10);
    t.create_tree(5);
    t.create_tree(3);
    t.create_tree(8);
    t.create_tree(15);
    t.create_tree(17);

    t.print_path(t.root);

    cout<<"height :"<<t.height_tree(t.root);

    t.delete_tree(5);

    t.print_path(t.root);
}
Last edited on
ne555 (10692)
After the 81-98 loop both p and trail have the same data. It could be null, or the node to be deleted.
Then you are screwed, as you cannot adjust the links

Lines 102, 108 and 125 do nothing.
agoswami (135)
Any suggestion to fix this issue. I have gone through the book and try to implement algorithm in c++. or my delete_tree function is completely wrong which need to write again
ne555 (10692)
You need to be able to link them, so don't stop where you find the data, but on its parent.
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