Its all about C++ Binary Trees

[Trista]

I'm trying to write an address book that is based on a binary tree. I'm devloping in Visual C++ (I blew up my Ubuntu with the new dist), starting with the basics:

#ifndef binarySearchTree_h
#define binarySearchTree_h

#include <string>
#include <iostream>

using namespace std;

//Define the node
struct treeNode
//An object of type TreeNode 
{
	string data;
	struct node* left;
	struct node* right;

treeNode(string str)
//constructor: Make a node containing str.
{
	data = str;
	left = NULL;
	right = NULL;
}

};

//define the class
class binarySearchTree
{
public:
	binarySearchTree(); 
		//constructor
	bool isEmpty() const;
	             //
	bool treeContains(treeNode *root, string data);
		//return true if item is one of the items in the 
		//binary sort tree to which root points. Return
		//false if not


protected:
	treeNode *root;
	
};
#endif

my problem is in the implementation file in the treecontains() function:

#include "binarySearchTree.h"

#include <string>
#include <iostream>

using namespace std;

binarySearchTree::binarySearchTree() :root(NULL)
{
}
bool binarySearchTree::isEmpty() const
		//return true if tree is empty
{
	return (root == NULL);
}
bool binarySearchTree::treeContains(treeNode *root, string data)     
		//return true if item is one of the items in the 
		//binary sort tree to which root points. Return
		//false if not
	{
		if(root==NULL)
			//tree is empty
		{
				return false;
		}
		if(data==root->data)
			//item has been found
		{
			return true;
		}

		
		if(data < root->data)
			//item is in left subtree
		{
			return treeContains(root->left, data);  //error
		}
		else
			//item is in right subtree
		{
			return treeContains(root->right, data); //error
		} 

	} //end treeContains()

I get an error that says:

Compiling...
test.cpp
binarySearchTree.cpp
c:\program files\microsoft visual studio\myprojects\binaryaddressbook\binarysearchtree.cpp(41) : error C2664: 'treeContains' : cannot convert parameter 1 from 'struct node *' to 'struct treeNode *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
c:\program files\microsoft visual studio\myprojects\binaryaddressbook\binarysearchtree.cpp(46) : error C2664: 'treeContains' : cannot convert parameter 1 from 'struct node *' to 'struct treeNode *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
Error executing cl.exe.

binaryAddressBook.exe - 2 error(s), 0 warning(s)

Here is my test file:

#include "binarySearchTree.h"

#include <iostream>

using namespace std;

int main()
{

	treeNode *root;  //pointer to the root noode in the tree
	root = NULL;  //start with an empty tree



	return 0;
}

as you can see it doesn't do anything, but get the constructors working.

please help so I can get this thing going?

thank you

 

[0rthodontist]

I'm trying to write an address book that is based on a binary tree. I'm devloping in Visual C++ (I blew up my Ubuntu with the new dist), starting with the basics:

#ifndef binarySearchTree_h
#define binarySearchTree_h

#include <string>
#include <iostream>

using namespace std;

//Define the node
struct treeNode
//An object of type TreeNode 
{
	string data;
	struct node* left;
	struct node* right;

treeNode(string str)
//constructor: Make a node containing str.
{
	data = str;
	left = NULL;
	right = NULL;
}

};

It's been years since I've used C++ but I think you should have struct treeNode* left; and struct treeNode* right;.

 

[nmtim]

Yep: TreeNode needs pointers to TreeNode, not pointers to struct node.

Cheers,
Tim

 

[Trista]

You are so right! Thank you!