Need Help with Binary Search Trees

[Hexar90]

I am a beginner programmer going to school. I am having a tough time trying to write my binary tree into a file. I figured out how to read a file to a binary tree but I am not sure how to right it back in. What I was seeing in the forums it only shows one variable and I've tried to adjust it to my variables which I cannot figure it out. Below is my source code. If anyone could help me understand how to write a binary search tree into a file that would be awesome! Thank you in advance.

#include <iostream>
#include <fstream>
#include <string>
#include "Windows.h"
using namespace std;

//Binary Tree Class
class BinarySearchTree
{
    private:
        struct tree_node
        {
           tree_node* left;
           tree_node* right;
	   string softwareCode;
	   string softwareName;
	   string softwareVersion;
	   string softwarePrice;
        };
        tree_node* root;
    
    public:
        BinarySearchTree()
        {
           root = NULL;
        }
       
        bool isEmpty() const { return root==NULL; }
        void print_inorder();
        void inorder(tree_node*);
        void insert(string, string, string, string);
        void remove(string, string, string, string);
        void write_node(tree_node*);
        void writeToFile();
};

// Smaller elements go left
// larger elements go right
void BinarySearchTree::insert(string code, string name, string version, string price)
{
    tree_node* t = new tree_node;
    tree_node* parent;
    t->softwareCode = code;
    t->softwareName = name;
    t->softwareVersion = version;
    t->softwarePrice = price;
    t->left = NULL;
    t->right = NULL;
    parent = NULL;
    
    // is this a new tree?
    if(isEmpty()) root = t;
    else
    {
        //Note: ALL insertions are as leaf nodes
        tree_node* curr;
        curr = root;
        // Find the Node's parent
        while(curr)
        {
            parent = curr;
            if(t->softwareCode > curr->softwareCode) curr = curr->right;
            else curr = curr->left;
        }

        if(t->softwareCode < parent->softwareCode)
           parent->left = t;
        else
           parent->right = t;
    }
}

//print Tree in order
void BinarySearchTree::print_inorder()
{
  inorder(root);
}

//sorting the tree
void BinarySearchTree::inorder(tree_node* p)
{
    if(p != NULL)
    {
        if(p->left) inorder(p->left);
        cout << "Software Code: " << p->softwareCode << endl;
        cout << "Software Name: " << p->softwareName << endl;
        cout << "Software Version: " << p->softwareVersion << endl;
        cout << "Software Price: $" << p->softwarePrice << endl << endl;
        if(p->right) inorder(p->right);
    }
    else return;
}

void BinarySearchTree::writeToFile()
{
	write_node(root);
}

void BinarySearchTree::write_node(tree_node*p)
{
	string code, name, version, price;
	
	ofstream file("newsoftware.txt");
	
	file.is_open();
	
	if(p != NULL)
	{
	     if(p->left) inorder(p->left);
	     file << p->softwareCode << endl;
       	     file << p->softwareName << endl;
             file << p->softwareVersion << endl;
             file << p->softwarePrice << endl << endl;
      	     if(p->right) inorder(p->right);
	}
}

[dhayden]

The problem is at line 103. You open the file for each node written, which means that each node writes at the beginning of the file. Open the file in writeToFile and pass the stream to write_node(). Something like:

void BinarySearchTree::writeToFile()
{
	ofstream file("newsoftware.txt");
	write_node(root, file);
}

void BinarySearchTree::write_node(tree_node*p, ostream &file)
{
	string code, name, version, price;
			
	if(p != NULL)
	{
	     if(p->left) inorder(p->left, file);
	     file << p->softwareCode << endl;
       	     file << p->softwareName << endl;
             file << p->softwareVersion << endl;
             file << p->softwarePrice << endl << endl;
      	     if(p->right) inorder(p->right, file);
	}
}

[Mantorr22]

dhayden wrote:

The problem is at line 103. You open the file for each node written, which means that each node writes at the beginning of the file. Open the file in writeToFile and pass the stream to write_node().

That is not entirely correct. write_node is NOT a recursive function.
The function calls inorder() recursively, but inorder() does not write data into a file.

Somehow between these lines to fix this :

void BinarySearchTree::write_node(tree_node*p)
{
	string code, name, version, price;
	
	ofstream file("newsoftware.txt");
	
	file.is_open();
	
	if(p != NULL)
	{
	     if(p->left) inorder_write(p->left, file);
	     file << p->softwareCode << endl;
       	     file << p->softwareName << endl;
             file << p->softwareVersion << endl;
             file << p->softwarePrice << endl << endl;
      	     if(p->right) inorder_write(p->right, file);
	}
}

void BinarySearchTree::inorder_write(tree_node* p, ostream &file)
{
    if(p != NULL)
    {
        if(p->left) inorder_write(p->left, file);
        file << "Software Code: " << p->softwareCode << endl;
        file << "Software Name: " << p->softwareName << endl;
        file << "Software Version: " << p->softwareVersion << endl;
        file << "Software Price: $" << p->softwarePrice << endl << endl;
        if(p->right) inorder_write(p->right, file);
    }
    else return;
}

[Hexar90]

Thank you all. It worked. I couldn't have done it without you. Thank you again so much.