Design an algorithm and write code to serialize and deserialize a binary tree.

Design an algorithm and write code to serialize and deserialize a binary tree.

Writing the tree to a file is called 'serialization' and reading back from the file to reconstruct the exact same binary tree is 'deserialization'.

 

Solution:

// TreeSerialAndDeserial.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <fstream>
#include <string>
#include <iostream>
using namespace std;
class Tree
{
public:
	Tree(Tree* left, Tree* right, int val);
	Tree* setLeft(Tree* node, Tree* left) {node->left = left;}
	Tree* setRight(Tree* node, Tree* right) {node->right = right;}
	Tree* getLeft(Tree* node) {return node->left;}
	Tree* getRight(Tree* node) {return node->right;}
	void setVal(Tree* node, int val) {node->val = val;}
	int getVal(Tree* node) {return node->val;}
	void deserialize(Tree*& tree,string path);						// from file to tree, not serialize
	void serialize(Tree* tree, const string& path);		// from tree to file, serialize(plain storage)
	void insertNode(Tree* tree,Tree* node);

private:
	Tree* left;
	Tree* right;
	int val;

};    //dont forget ";" here

Tree::Tree(Tree* left, Tree* right, int val)
{
	this->left = left;
	this->right = right;
	this->val = val;
}

void Tree::insertNode(Tree* tree,Tree* node)
{
	
	Tree* tree_prt = tree;
	bool flag = false;
	if(tree == NULL)
		return;
	else
	{
		while(tree)
		{
			if(tree->val > node->val)
			{
				tree_prt = tree;
				tree = tree->left;
				flag = true;
			
			}
			else
			{
				tree_prt = tree;
				tree = tree->right;
			}
		}

		tree = node;
		if(flag) tree_prt->left = tree;
		else  tree_prt->right = tree ;
	}

}
void Tree::deserialize(Tree*& tree,string path)
{
	ifstream ifile;
	ifile.open(path,std::ifstream::in);
	int temp = 0;
	while(ifile >> temp )
	{
		if(!tree)
		{
			tree = new Tree(NULL, NULL, temp);
		}
		else
		{
			Tree* node = new Tree(NULL, NULL, temp);
			insertNode(tree,node);
		}
	
	}
}
void Tree::serialize(Tree* tree,const string& path) //preorder tree, easiest way to do this
{
	ofstream ofile;
	if(!ofile.is_open())
	{
		ofile.open(path,std::ofstream::out);
	}
	
	if(!tree)
		return;
	else
	{
		ofile << tree->val;
		serialize(tree->left,path);
		serialize(tree->right,path);
	}
}
int _tmain(int argc, _TCHAR* argv[])
{
	Tree* tree = NULL;
	tree->deserialize(tree,"c:/out.txt");
	tree->serialize(tree,"c:/in.txt");


	return 0;
}