Data Structures Program on Tree Search

      #include< iostream >
  #include< cstdlib >
  #include< string >
  using namespace std;
  struct tree
  {
     int info;
     tree *Left, *Right;
  };
  tree *root;
  class Binary_tree
  {
     string path;
     public:
       Binary_tree();
       void insert1(int);
       tree *insert2(tree *, tree *);
       void search(int);
       void pretrav(tree *);
       void intrav(tree *);
       void posttrav(tree *);
  };
  Binary_tree::Binary_tree()
  {
     root = NULL;
  }
  tree* Binary_tree::insert2(tree *temp,tree *newnode)
  {
     if(temp==NULL)
     {
       temp=newnode;
     }
     else if(temp->info < newnode->info)
     {
       insert2(temp->Right,newnode);
       if(temp->Right==NULL)
         temp->Right=newnode;
     }
     else
     {
       insert2(temp->Left,newnode);
       if(temp->Left==NULL) temp->Left=newnode;
     }
     return temp;
  }
  void Binary_tree::insert1(int n)
  {
     tree *temp=root,*newnode;
     newnode=new tree;
     newnode->Left=NULL;
     newnode->Right=NULL;
     newnode->info=n;
     root=insert2(temp,newnode);
  }
  void Binary_tree::pretrav(tree *t = root)
  {
     if(root == NULL)
     {
       cout<<"Nothing to display";
     }
     else if(t != NULL)
     {
       cout<< t->info<<" ";
       pretrav(t->Left);
       pretrav(t->Right);
     }
  }
  void Binary_tree::intrav(tree *t = root)
  {
     if(root==NULL)
     {
       cout<<"Nothing to display";
     }
     else if(t!=NULL)
     {
       intrav(t->Left);
       cout<< t->info<<" ";
       intrav(t->Right);
     }
  }
  void Binary_tree::posttrav(tree *t = root)
  {
     if(root==NULL)
     {
       cout<<"Nothing to display";
     }
     else if(t!=NULL)
     {
       posttrav(t->Left);
       posttrav(t->Right);
       cout<< t->info<<" ";
     }
  }
  void Binary_tree::search(int key)
  {
     tree *temp=root,*parent=root;
     path = "";
     if(temp==NULL)
     {
       cout<<"The tree is empty"<< endl;
     }
     else
     {
       path = "root";
       while(temp!=NULL && temp->info!=key)
       {
         parent=temp;
         if(temp->info< key)
         {
           temp=temp->Right;
           path += "->Right";
         }
         else
         {
           temp=temp->Left;
           path += "->Left";
         }
       }
     }
     if(temp==NULL)
     {
       cout<<"Key not found!";
     }
     else
     {
       cout<<"Key is found\n";
       cout<<"Paht is: ";
       cout<< path;
     }
  }
  int main()
  {
     Binary_tree bt;
     int choice, n, key;
     while(1)
     {
       cout<<"\n\t1. Insert\n\t2. Search\n\t3. Preorder Traversal\n\t4. Inorder Treversal\n\t5. Postorder Traversal\n\t6. Exit"<< endl;
       cout<<"Enter your choice: ";
       cin>>choice;
       switch(choice)
       {
         case 1:
           cout<<"Enter item: ";
           cin>>n;
           bt.insert1(n);
           break;
         case 2:
           cout<<"Enter element to search: ";
           cin>>key;
           bt.search(key);
           break;
         case 3:
           cout<< endl;
           bt.pretrav();
           break;
         case 4:
           cout<< endl;
           bt.intrav();
           break;
         case 5:
           cout<< endl;
           bt.posttrav();
           break;
         case 6:
           exit(0);
       }
     }
     return 0;
  }