Huffman.h

#include <string>
#include <iostream>
#include <fstream>
#ifndef HUFFMAN
#define HUFFMAN
class Huffman
{
private:
	/*** Node structure ***/
	class BinNode
	{
	public:
		char data;
		BinNode * left, *right;
		// BinNode constructor
		BinNode(char item)
		{
			data = item;
			left = right = 0;
		}
	};
	typedef BinNode * BinNodePointer;

public:
	/*** Function members ***/
	Huffman();
	/*---------------------------------------------------------------------------------
	Constructor
	Precondition: None.
	Postcondition: A one-node binary tree with root node pointed to by myRoot
	has been created.
	---------------------------------------------------------------------------------*/
	void buildDecodingTree(ifstream & codeIn);
	/*---------------------------------------------------------------------------------
	Build the Huffman decoding tree.
	Precondition: ifstream codeIn is open and is connected to a file that contains
	characters and their codes.
	Postcondition: A oneHuffman decoding tree has been created with root node
	pointed to by myRoot.
	---------------------------------------------------------------------------------*/
	void insert(char ch, string code);
	/*---------------------------------------------------------------------------------
	Insert a node for a character in Huffman decoding tree.
	Precondition: code is the bit string that is the code for ch.
	Postcondition: A node containing ch has been inserted into the Huffman tree
	with root pointed to by myRoot.
	---------------------------------------------------------------------------------*/
	void decode(ifstream & messageIn);
	/*---------------------------------------------------------------------------------
	Build the Huffman decoding tree.
	Precondition: ifstream messageIn is open and is connected to a file that
	contains the message to be decoded.
	Postcondition: The decoded message has been output to cout.
	---------------------------------------------------------------------------------*/
	void printTree(ostream & out, BinNodePointer root, int indent);
	/*---------------------------------------------------------------------------------
	Recursive function to display a binary tree with root pointed to by root.
	Precondition: ostream out is open; root points to a binary tree; indent >= 0
	is the amount to indent each level..
	Postcondition: Graphical representation of the binary tree has been output
	to out.
	---------------------------------------------------------------------------------*/
	void displayDecodingTree(ostream & out);
	/*---------------------------------------------------------------------------------
	Display the decoding tree.
	Precondition: ostream out is open.
	Postcondition: The decoding tree has been output to out (via printTree().)
	---------------------------------------------------------------------------------*/
	/*** Data members ***/
private:
	BinNodePointer myRoot;
};

//--- Definition of constructor
inline Huffman::Huffman()
{
	myRoot = new BinNode('*');
}
//--- Definition of displayDecodingTree()
inline void Huffman::displayDecodingTree(ostream & out)
{
	printTree(out, myRoot, 0);
}

#endif