"See here for some alternatives"

I see, but that alternative treats the input as a number, and as a result, you may lose precision sometimes.

"Speaking of qbasic: this is a kind of Retro computing, isn't it?"

Yes, I am a member of several old computer groups and BASIC groups on Facebook. I also like Windows XP and TinyPerl 5.8 which are both considered ancient stuff. But I like to push the limits to see how much modern stuff we can do with old hardware and software.