in reply to Re^2: Add numbers row by row
in thread Add numbers row by row

> Where could I learn something about this string?

You either type "perldoc -fprintf" or sprintf into your console ...

... or you check the online docs at http://perldoc.perl.org (but beware of the Perl version)

It's also searchable per "duckduckgo: perl printf" or "google: perl printf" or other search machines...

Cheers Rolf

( addicted to the Perl Programming Language)