Programming

#include <iostream.h>
struct mytree
{
  int element;
  mytree * left;
  mytree * right;
}*root;
class tree
{
  public:
  int size(mytree * new_t);
  mytree* insert(int a, mytree * new_t );
};
int tree:: size(mytree * new_tr)
{
  if(new_tr==NULL)
  {
    return (0);
  }
  else
  {
    return ((size(new_tr -> left)) + (size(new_tr -> right)) + 1);
  }
}

///////////////////////////////////////////
mytree* tree::insert(int a, mytree * new_t )
{
  if(new_t == NULL)
  {
    new_t->element = a;
    new_t->right = NULL;
    new_t -> left =NULL;
    cout << "very first insert";
  }
  else
  {
    if (a <= new_t -> element)
    {
      if (new_t -> left != NULL)
      {
        cout <<" first small insert";
        insert(a, new_t->left);
      }
      else
      {
        cout << "first final small insert";
        mytree * node = new mytree;
        new_t -> left = node;
        new_t -> left -> element = a;
        new_t -> left -> left = NULL;
        new_t -> left -> right = NULL;
      }
    }
    if (a > new_t -> element)
    {
      if (new_t -> right != NULL)
      {
        cout << "first greator insert";
        insert(a, new_t -> right);
      }
      else
      {
        mytree * node = new mytree;
        new_t -> right = node;
        new_t -> right -> element = a;
        new_t -> right -> left = NULL;
        new_t -> right -> right = NULL;
        cout << "first greator final insert";
      }
    }
  }
}
int main()
{
  tree * a = new tree;
  int no_add,this_element, sizet;
  char choice;
  this_element=0;
  mytree * tree1 = new mytree;

  cout <<"enter no of elements to be added ";
  cin >> no_add;
  for(int i=0; i < no_add; i++)
  {
    cout << "what to add at element "<< i<< " ? "<<endl ;
    cin >> this_element;
    tree1 = a->insert(this_element, tree1);
  }
  cout << "need to know size ? y or n "<< endl;
  cin >> choice;
  if (choice == 'y')
  {
    sizet = a-> size(tree1);
    cout << " size of tree is " << endl ;
    cout << sizet;
  }
  else
  {
    cout << " program ends here";
  }
  return 0;
}