Project 4: Implement a fast Huffman encoding algorithm

Due: Monday 11/9/2009

For this assignment you will implement the "huffTree" class, a modified "AVLTree" class, and a modified "minHeap" class, to implement a fast Huffman encoding algorithm. The final result will be a program that reads in a text file and writes to an output file the binary encoding for each character in the file according to Huffman's algorithm. For efficient grading, please use my test code given below.

#include <fstream>

#include "AVLTree.h"

#include "minHeap.h"

#include "huffTree.h"

using namespace std;

void readAndInsert(AVLTree &avltree, ifstream & ifile)

{

while( ! ifile.eof() )

{

char tmp = ifile.get();

avltree.insertItem( tmp );

}

}

int main()

{

ifstream ifile;

ofstream ofile;

//open input and output files

ifile.open("story.txt");

ofile.open("report.txt");

//read in each character of input file, insert into a BST

AVLTree avltree;

readAndInsert(avltree, ifile);

//For each node in the BST, create a huffman tree,

//and insert into a min heap

minHeap heap(1000);

avltree.loadHeap(heap);

//while the heap has more than 1 huffTree, get 2 smallest,

//merge them together, and put merged tree back in heap

huffTree * h1;

huffTree * h2;

while( heap.getSize() > 1 )

{

h1 =heap.extractMin();

h2 =heap.extractMin();

heap.insert(new huffTree(h1,h2));

}

//take remaining huffTree, use to create a table of

//codes for each char, write to output file

huffTree * finalTree = heap.extractMin();

finalTree->makeReport(ofile);

//close files

ifile.close();

ofile.close();

return 0;

}