LZW

#include <codecogs/computing/io/compression/lzw.h>
#include <iostream>

// the number of characters to generate in the sample array
#define N 10000

using namespace Computing::IO::Compression;

int main()
{
  // initialize random seed
  srand(time(0));

  // generate an array of N random letters
  std::vector<unsigned char> sample;
  for (int i = 0; i < N; ++i)
    sample.push_back('A' + rand() % ('Z' - 'A' + 1));

  // compress the sample array
  std::vector<unsigned char> compressed = LZW::compress(sample);

  // decompress the compressed array
  std::vector<unsigned char> uncompressed = LZW::decompress(compressed);

  // compare the sizes of the compressed and uncompressed arrays
  std::cout << "      Size of the sample array: " << N << std::endl;
  std::cout << "  Size of the compressed array: " << compressed.size() << std::endl;
  std::cout << "Size of the uncompressed array: " << uncompressed.size() << std::endl;

  std::cout << std::endl;

  // test if the sample and the uncompressed arrays are identical
  // this proves that the LZW compression algorithm does not affect the initial data
  bool identical = (N == uncompressed.size());
  for (size_t i = 0; identical && i < uncompressed.size(); ++i)
    if (sample[i] != uncompressed[i])
      identical = false;

  if (identical)
    std::cout << "The sample and uncompressed arrays are identical." << std::endl;
  else
    std::cout << "Error! The sample and uncompressed arrays are NOT identical." << std::endl;

  return 0;
}

Output

Size of the sample array: 10000
  Size of the compressed array: 7621
Size of the uncompressed array: 10000

The sample and uncompressed arrays are identical.