$ perl -e'printf "%d\n", $_ for 4.9999999999, 5'
4
5

##</code><code>##

$ perl -e'printf "%.0f\n", $_ for 4.9999999999, 5'
5
5

##</code><code>##

$ perl -e'printf "%.0f\n", $_ for 5.4999999999, 5.5'
5
6

##</code><code>##

$ perl -e'printf "%.0f\n", sprintf "%.8f", $_ for 5.4999999999, 5.5'
6
6