Short description:

Atbash is a simple substitution cipher that maps each letter to its "mirror" in the alphabet (for example A↔Z, B↔Y, etc.). It is primarily used for illustrative purposes and simple obfuscation.

Implementation:

• Implementations are provided in C and C++ (see C/ and C++/).
• Tests and example usage files are included to verify correctness.
• C/Atbash.c, C/AtbashTest.cpp — C implementation and tests.
• C++/Atbash.h, C++/AtbashTest.cpp — C++ header and tests.

Algorithm (brief):

1. For each input letter in the Latin alphabet determine its position (A=0..Z=25).
2. Compute the mirrored position: mirrored = 25 - pos.
3. Replace the letter with the letter at the mirrored position, preserving case.
4. Non-letter characters are preserved unchanged.

Example:

Input: "Hello, World!" Output: "Svool, Dliow!"