Program giving segmentation fault error

Here, is my code

#include<iostream>
using namespace std;
int get_data;
struct node
{
  int data;
  node *left, *right;
}*root,*new_node;

class binary_terr
{
public:

  void insert_node(node *tree, node *new_node);
  void delete_node(node *tree);
  binary_terr()
  {
    root = NULL;
  }
};
int main()
{
 int in_data, i=0;
 binary_terr bin;

 while(i < 6)
 {
   new_node = new node;
   cout<<"Enter the data you want to insert";
   cin>>in_data;
   new_node->data = in_data;
   bin.insert_node(root, new_node);
 //new_node = NULL;
   cout<<"\n"<<"value of iterator"<<i<<"\n";
   ++i;
 }
 cout<<"Enter data you want to find";
 bin.delete_node(root);
 return 0;
}

void binary_terr :: insert_node(node *tree, node *new_node)
{
//  tree = new_node;
  if(root == NULL)
  {
    root = new node;
    cout<<"root created";
    root->data = new_node->data;
    root->left = NULL;
    root->right = NULL;
    return;
  }
  else if((tree->data) > (new_node->data))
  {
    if(tree->left != NULL)
    {
      insert_node(tree->left, new_node);
    }
    else
    cout<<"Node attach to left of tree"<<tree->data;
    {
      tree->left = new_node;
      (tree->left)->left = NULL;
      (tree->left)->right = NULL;
      return;
    }
  }
  else
  {
    if(tree->right != NULL)
    {
      insert_node(tree->right, new_node);
    }
    else
    {
      cout<<"Node attach to right of tree"<<tree->data;
      tree->right = new_node;
      (tree->right)->left = NULL;
      (tree->right)->right = NULL;
      return;
    }
  }
};
void binary_terr :: delete_node(node *tree)
{
  if (tree->data > get_data)
  {
    if((tree->data) != get_data)
    {
      delete_node(tree->left);
    }
    else
    {
      cout<<"Data find on left side of tree";
    }
  }
  else
  {
    if((tree->data) != get_data)
    {
      delete_node(tree->right);
    }
    else
    {
      cout<<"Data is find on right side of tree";
    }
  }
}

When i am executing the code. I got following error:

Enter the data you want to insert34

root created

value of iterator0

Enter the data you want to insert23

Node attach to left of tree34

value of iterator1

Enter the data you want to insert12

Node attach to left of tree23

value of iterator2

Enter the data you want to insert54

Node attach to right of tree34

value of iterator3

Enter the data you want to insert65

Node attach to right of tree54

value of iterator4

Enter the data you want to insert76

Node attach to right of tree65

value of iterator5

Segmentation fault (core dumped)

So, where is exactly problem. I appreciate your help thanks!.