Code challenge: Timer

Question

Task: make a timer that does Not need to be in separate thread. Max. error – 0.1sec.
Tools: any language.
Restrictions: do not use Thread.Sleep() or analogs to measure time sequences; do not system timers.

Answer 1

My friend made this code;
https://code.sololearn.com/W1KukJwuBg1c/?ref=app

Answer 2

Pretty unfortunate for the non-web folk 😔