Update: This is not a foreign language translator or some such code. This is a standard C++ 17 utility to transform the core character sets between each other. The first 127 characters, that is. As a such it is remarkably useful and simple. For full blown, locale aware solutions please look elsewhere, starting from here. End of update.
Standard C++ std lib, is one very complete and useful library. But there are times when you do realize you can build one or two of very simple utilities on top of it.