tree 1

#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<alloc.h>
#include<dos.h>

enum bool{true,false};
typedef struct TreeNode* link;

struct TreeNode {

int item;      // The data in this node.
link left;    // Pointer to left subtree.
link right;   // Pointer to right subtree.



      };


struct BinaryTree{

   link root;


    };
void initTree(link &troot)
{
troot=NULL;
}

void treeInsert(link &troot,int newItem) {

if(troot==NULL){
 link temp;
temp=(TreeNode*)malloc(sizeof(TreeNode));
 temp->item=newItem;
 temp->left=NULL;
  temp->right=NULL;
  troot=temp;
 return;
     }

 else if ( newItem <troot->item ) {
    treeInsert( troot->left, newItem );
 }
 else {
    treeInsert( troot->right, newItem );
 }

       }

void preordertraverse( link troot ) {

if ( troot != NULL ) {
  cout << troot->item << " ";      // Print the root item.
  preordertraverse( troot->left );    // Print items in left subtree.
  preordertraverse( troot->right );   // Print items in right subtree.
   }
     }

void postordertraverse( link troot ) {

if ( troot != NULL ) {
  postordertraverse( troot->left );    // Print items in left subtree.
  postordertraverse( troot->right );   // Print items in right subtree.
  cout << troot->item << " ";       // Print the root item.
}
     }

void inordertraverse( link troot ) {

if ( troot != NULL ) {
 inordertraverse( troot->left );    // Print items in left subtree.
  cout << troot->item << " ";     // Print the root item.
  inordertraverse( troot->right );   // Print items in right subtree.
}
     }

bool treeContains( link troot, int item ) {

    if ( troot == NULL ) {
  // Tree is empty, so it certainly doesn't contain item.
return false;
    }
    else if ( item == troot->item ) {
  // Yes, the item has been found in the root node.
return true;
    }
    else if ( item < troot->item ) {
  // If the item occurs, it must be in the left subtree.
return treeContains( troot->left, item );
    }
    else {
  // If the item occurs, it must be in the right subtree.
return treeContains( troot->right, item );
    }
 }

void main(){
    clrscr();
      BinaryTree *bt;
      initTree(bt->root);

     treeInsert(bt->root,100);

      treeInsert(bt->root,90);
      treeInsert(bt->root,120);
      treeInsert(bt->root,70);
      treeInsert(bt->root,95);
      treeInsert(bt->root,130);
      cout<<"inserted items : 100 90 120 70 95 130\n\n";

      cout<<"Inorder traverse : \n\n";
   inordertraverse(bt->root);
   cout<<"\n\n";
   cout<<"post order traverse : \n\n";
   postordertraverse(bt->root);
   cout<<endl<<endl;
   cout<<"preorder traverse :\n\n";
   preordertraverse(bt->root);
   cout<<endl;
   getch();

 }