How to autocomplete in the interactive console?

Question

C++ / C#

When you enter a phone number into the console, a prompt should appear. Enter in green letters. Part of the hint is gray. The hint numbers are taken from the saved number file. For example, the user entered "897", the file has a saved number (numbers) with the same beginning, then the first one found is selected and its remainder is substituted in gray at the end of the input line. In this case, the input cursor does not go to the end of the line. If the user presses ENTER with a half entered number, then the number is appended

Answer 1

I would intercept keystrokes with Console. ReadKey(true) and render any output you want with cursor shift and Console.Write