Looking for the font of this book programming section

[Member Doo…]

The code is from a C++ book

I must say that is a book made by a programming community and there is no author to ask about the font.

There is no information about how the book was written.

Thank you !

[Member Ric…]

Roboto Mono.

[Member Doo…]

Thank you very much. How do you recognise the fonts ? You succed everytime.