Well, when you're writing a console program, you can assume your font is monospaced and you can assume you have a function like wcwidth() that will tell you how many monospaced cells a string will take up.
I know that eev.ee points out that wcwidth() is inconsistent (emoji screwed it up, then Unicode 9 gave a consistent width to emoji, but most libraries aren't on Unicode 9 so the situation is currently more inconsistent than before). But the situation is a lot better than just saying "I don't know, blame fonts".
Do unicode strings really have a rendered length?
https://eev.ee/blog/2015/09/12/dark-corners-of-unicode/#comb...
> So the “length” of ... characters depends ... on the display font