[SOLVED] Arduino-PrintStream library error. Fixable?

I got a C++ book and have been doing some of the example programs. cout/cin is used throughout and two programs in I've tired of converting cout statements to sprintf/Serial... - besides, there's the error-proneness aspect. A search led me to this thread and a link to a library which purportedly bestows cout-like ability on the Arduino (IDE 1.8.2).

My first attempt with one of the sample programs from the book didn't work so I tried the library's example program. No joy there either. Both return this error:

C:\Users\Owner\Documents\Arduino\libraries\Arduino-PrintStream-master\src\PrintStream.cpp:23:11: error: 'class Print' has no member named 'flush'

   printer.flush();

           ^

Is there something else simple I need to do to make this work?

If not, could the solution be as simple as commenting out all references to flush in the .cpp file?

The GitHub page doesn't provide anything I can see as far as contacting the author. To my eye it looks like it's been abandoned, but then, I'm not all that familiar with GitHub.

Class Print has flush() in most of the cores. What Arduino core/board-package do you use?

I have an UNO. Thanks.

dougp:
I have an UNO. Thanks.

in IDE use the Board Manager to update the AVR core to 1.6.21

flush method was moved up from Stream to Print on Oct 24, 2014

Juraj:
in IDE use the Board Manager to update the AVR core to 1.6.21

flush method was moved up from Stream to Print on Oct 24, 2014

Worked like a charm! Thanks!