You have to be careful about the signed/unsigned operations and use `wrapping` arithmetics to avoid panics due to unsigned *carry* and signed *overflow*.
Use borrowed array slices as arguments to `decode`.
Use borrowed array slices as arguments to `decode`.
The `seed`, `abc`,`coded` and `plain` should be stack allocated. The decoded string should be printed when decryption is finished.
b. Make the `seed`, `abc`,`coded` and `plain` heap allocated. Accessing those will require some `unsafe` code. (Keep the unsafe blocks as local as possible.)
b. Make the `seed`, `abc`,`coded` and `plain` heap allocated. Accessing those will require some `unsafe` code. (Keep the unsafe blocks as local as possible, perhaps you can do all in *safe* Rust.)
c. Safety analysis. Provoke the implementation, by omitting the `'\0'` (null termination). Observe the result and motivate the behavior in terms of your understanding of the Rust memory model. Under which circumstances do you consider 3a and 3b to have same/different memory safety.
