Default sha256 algorithm implemented in C++ just to understand length extension attacks better. Not fit for production, obviously. Why would you even ask? I have an idea: You explain smart pointers to me and I will make valgrind shut up.
There already is a binary file you can download directly. To compile it yourself you need a C++ compiler. Your installed version will most likely work.
git clone https://github.com/ny64/sha256.git
cd sha256
g++ src/*.cpp -o sha256
sha256 "String 1" "String 2" ...
Returns list of hashes like
9ab25acb49b0ee82a6f395549aff98255b89d7eb4dcb2cdc6100550867acb1a4
ee94765bb93df4b023a1e6aad1d82e2c6ae0b7635c6fb2673dc5457abf7070d0
...