What projects on C do you recommend for the beginner?

Question

I'm new to C and know only standard pack of it: Io, math, string headers... also I am confident in its syntax.

I would like to have more practice it it, probably something connected to software/ cryptography (absolutely new to it, but interested)/ ds(I know, that python/C++ are better for it, but still).

Waiting for your tips

Answer 1

Calculator

Answer 2

I found a solution - implementation of some data compressing algorithms as zip decoding.