http://www.perlmonks.org?node_id=1001137


in reply to Best way to round a number.

use strict;
use warnings;


sub round5 {
  my $num = shift;

  return $num+2 - ($num+2) % 5; # <------ TIMTOWTDI ;-)
}



for (0..10) {
  printf "%3d -> %3d    %3d -> %3d\n",
    $_, round5($_), -$_, round5(-$_);
}

__DATA__

  0 ->   0      0 ->   0
  1 ->   0     -1 ->   0
  2 ->   0     -2 ->   0
  3 ->   5     -3 ->  -5
  4 ->   5     -4 ->  -5
  5 ->   5     -5 ->  -5
  6 ->   5     -6 ->  -5
  7 ->   5     -7 ->  -5
  8 ->  10     -8 -> -10
  9 ->  10     -9 -> -10
 10 ->  10    -10 -> -10

[download]

In Section Seekers of Perl Wisdom