This is a WinRAR-like program developed in my second year of college using binary trees and lists. In this project we were asked to develop a program that would read an file and zip/unzip it based on the Huffman encoding.
The idea of it was that, receiving in the terminal both the word for compacting/descompacting and the name of the file, the program should create another file with .comp temination, if the word received in the terminal was Compacta, and creace an file with the original termination if the word was Descompacta.
This cryptography system creates a binary tree based on how often a character appears in a file. The more often it appears, higher will be the position of the character in the binary tree. After creating the tree, the values (in the ASCII table) of each character will be replaced by another value, determined by the position of the character in the tree. If the character is closer to the top of the tree (i.e appears very often in the file), it's new value will be smaller. If it is closer to the bottom of the tree (i.e appears rarely in the file), the value will be bigger.
In the first steps to this project, we created a code to read a file and sort the characters of it based on how often it appeared in the file. After this, we made a binary tree storing the characters and a table to relate the characters with it's new values based in the position of it in the tree. Everytime we access a right branch we add a 1 to the binary number representing the character and everytime we access a left branch, we add a 0.
In this stage, the program will create a new file with a .comp termination. The content that will be written in the new file is the bits of the character's new binary value. This new value is a lot smaller than what it used to be so, when we calculate the size of the file, it will be smaller than the size of the original file.
To use the program in the compacting mode, you have to execute it typing "./Compacta name_of_the_file.termination" in the terminal.
To use the program in this mode, you have to execute it typing "./Descompacta name_of_the_file.comp" in the terminal. You can only descompact a file that was previously compacted.
So in this stage, the program will recreate the original file by reading the compacted file and replacing the values of the characters with the old ones, in the ASCII table. So it will create another file, with the original termination, and decode the file received in the terminal.