encode-decode

Figure out how encoding algorithm, then write a decoder. C++ challenge. There will be a Part II.

Challenge Description

To complete this challenge, you will study the code in encoder.hpp to understand how it enciphers messages, then write a complementary decoder that will decipher them. This file is a header file. Header files serve to define functions and variables that may be used in other code by using the #include "headerFilename.h" statement (called an include directive) at the top of a .cpp file. This will allow you to call the functions or use the variables defined in the header file. To work with the files, click "Clone/Download" and download as a ZIP folder to get a local copy of encoder.hpp to work with. The file test.cpp is provided as an example. Your solution should be a header file named decoder.hpp. This file should contain a function with the signature:

string decoder(string input)

that will return the deciphered message as a string.

Working with the header file

The encoder is just a function in a header file. To use it, first compile the header file encoder.hpp (this example assumes you are compiling from the command line using either the GNU Compiler Collection (MINGW) or Clang. If you are using an IDE or other compiler follow your own procedure for compilation, just know that the header file must be compiled as well as any file that will use its functions):

g++ encoder.hpp <-----Using gcc/g++

clang encoder.hpp <-----Using LLVM Clang

Then in the same directory, create a .cpp file, #include the encoder header file, and call the encode(string input) function:

#include <iostream>
#include <string>
#include "encoder.hpp"

int main()
{
  string cipher;
  cipher = encode("Ich lebe mein Leben in wachsenden Ringen")
  std::cout << cipher << std::endl;
}

And compile:

g++ test.cpp -o test

clang test.cpp -o test.exe

Running the example should result in the output:

05144236900984036140552281044215368025217102941104612030003782521453900160661704200296114351

Submitting

In your browser, navigate to https://github.com/prgmng-challenge/encode-decode and click the "Fork" button at the top-right. Login to your Github account and you will have your own copy of this repository. On your computer, create a folder named GithubUsername-decoder containing ONLY your file, decoder.hpp. In your Github account, navigate to the 'submissions' folder, click 'Upload' and upload the folder. Finally, click "Create Pull Request", verify that everything is correct and finalize the pull request to complete your submission.

tgoodell/encode-decode

encode-decode

Challenge Description

Working with the header file

Submitting