num crate, it defines a private function called
get_radix_base. What is the meaning of this function?
It is an internal function for
to_str_radix which prints a number in given base.
Printing a binary bignum in the non-binary base
b (including decimal) is quite a daunting task, and while very rudimentary,
num crate uses a repeated division by some power of the base (
b^k) to get the lowest
k digits at a time. We want to maximize
b^k as long as it does not exceed one internal digit (“limb”, a type
BigDigit there) so that we can easily divide by
(maximal b^k, k in that case).