Question

I'm having some problems understanding the beginning of ps4, the Caesar Cipher. The set begins asking you to write two small functions, build_coder and build_encoder. The description for build_encoder tells you to use build_coder, but I can't figure out why they're both necessary. Both should return a dictionary with the original letters as keys and the encrypted letters as values. What's the difference?

Answer 1

For recursive solutions, a wrapper function is sometimes needed to initiate the recursion, which may be the case here.