Data Structures using C++

 #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; 
  }