

Task

Obtain a valid   Y   or   N   response from the keyboard.

The keyboard should be flushed, so that any outstanding key-presses are removed, preventing any existing   Y   or   N   key-press from being evaluated.

The response should be obtained as soon as   Y   or   N   are pressed, and there should be no need to press an   enter   key.




Program ObtainYN;
 
uses
  crt;
 
var
  key: char;
 
begin
  write('Your answer? (Y/N): ');
  repeat
    key := readkey;
  until (key in ['Y', 'y', 'N', 'n']);
  writeln;
  writeln ('Your answer was: ', key);
end.