This program is a Huffman Tree Implementation: 1- It takes the input from a file 2- Construct a frequency table for the different characters the input is composed of 3- Based on the frequency table, it creates a Huffman tree and a bitmap 4- Using the Bitmap, it encodes the input 5- Then, decode it again... Which means your input and output file have to be exactly the same ; otherwise, there is something wrong going on