Binary Tree – C++.

#include <iostream.h>

#include <stdlib.h>

       class node

      {

           private:

              int data;

              node *left;

              node *right;

              node *root;

            int Ctr;

           public:

              node()

                   {

                   Ctr=0;

                        root=NULL;

                   }

               void preorder(node *);

               void inorder(node *);

               void postorder(node *);

              node *insert(node *root,int val)

                   {

                        if(root==NULL)

                            {

                                root=new node();

                                root->left=root->right=NULL;

                                root->data=val;

                                Ctr++;

                            }

                        else if(Ctr%2==0)

                     {

                                root->left=insert(root->left,val);

                        }

                        else

                        {

                                root->right=insert(root->right,val);

                        }

                        return(root);

                   }

      };

  void node::inorder(node *root)

      {

           if(root!=NULL)

              {

                   inorder(root->left);

                   cout<<root->data;

                 inorder(root->right);

              }

       }

  void node::preorder(node *root)

      {

           if(root!=NULL)

              {

                   cout<<root->data;

                   preorder(root->left);

                   preorder(root->right);

              }

       }

  void node::postorder(node *root)

      {

           if(root!=NULL)

              {

                   postorder(root->left);

                   postorder(root->right);

                   cout<<root->data;

              }

       }

  int main()

      {

           node nD,*tree=NULL;

           int ch,val;

           do

              {

                   cout<<"\n\t\t***Binary Tree.***";

                   cout<<"\n\t1.Insert New Node.";

                   cout<<"\n\t2. PreOrder Traversal.";

                   cout<<"\n\t3. InOrder Traversal.";

                   cout<<"\n\t4. PostOder Traversal.";

                   cout<<"\n\t5. Exit.";

                   cout<<"\n\tChoice ? ";

                   cin>>ch;

                   switch(ch)

                        {

                            case 1:

                                cout<<"\n\tEnter Element : ";

                                cin>>val;

                                tree=nD.insert(tree,val);

                                break;

                            case 2:

                                 cout<<"\n\t **Pre-Order Traversal ** ";

                                 nD.preorder(tree);

                                 break;

                             case 3:

                                 cout<<"\n\t **In-Order Traversal ** ";

                                 nD.inorder(tree);

                                 break;

                             case 4:

                                 cout<<"\n\t **Post-Order Traversal ** ";

                                 nD.postorder(tree);

                                 break;

                             case 5:

                                 exit(0);

                        }

              }while(ch!=5);

           return 0;

      }