use strict;
use warnings;

########
# This version takes two arguments
#    The number to round
#    And the number of places to the right or left of the decimal point
#       Positive numbers to the left, negative numbers to the right.
#       Think powers of 10.
#
# Parts of this were stolen from nodeid=8781, and nodeid=1873
# most notably from Roy Johnson and wrvhage
########
sub round {
    my ($number, $places) = @_;
    my $sign = ($number < 0) ? '-' : '';
    my $abs = abs($number);

    if($places < 0) {
        $places *= -1;
        return $sign . substr($abs+("0." . "0" x $places . "5"),
                              0, $places+length(int($abs))+1);
    } else {
        my $p10 = 10**$places;
        return $sign . int($abs/$p10 + 0.5)*$p10;
    }
}

########
# Simple Ceiling function
########
sub ceil {
        my ($num) = @_;
        return int($num) + ($num > int($num));
}

########
# Function modeled after Excel's two argument function
#    Number to act on
#    Interval to return (2 would return only multiples of 2, 3 multiples of 3 etc)
########
sub ceil_xl {
    my ($num,$interval) = @_;

    return ceil($num / $interval) * $interval;
}

########
# Function derived from node_id=270920
#    Returns next nearest mulitple of 5 up to 50, then nearest 25 up to 100, 
#    then nearest quarter of current power of 10.
########
sub ceil_qtrs {
    my ($num) = @_;

    my $abs=int(abs($num));
    my $interval;

#  This next line was the originally given answer from Abigail-II,
#  it was obtuse enough that I needed to break it down to fully understand it,
#  then I wanted to modify it, and I then left my version in the more readable
#  style.
#      my $frac = $num < 100 ? 5 : (1 . ("0" x (length ($num) - 1))) / 4;

    if($abs < 40) {
        $interval = 5;
    } elsif($abs < 100) {
        $interval = 25;
    } else {
        $interval = "1".("0"x(length($abs)-1));
        $interval = $interval/4;
    }

    return ceil($num / $interval) * $interval;
}


my @data = qw(1 2 3.14159 4.634 5 5.165 6 9 10 10.257 13 23 89 99 100 101 214 702 1328
   -1 -2 -3.14159 -4.634 -5 -5.165 -6 -9 -10 -10.257 -13 -23 -89 -99 -100 -101 -214 -704 -1328
);


my $format = "  "."%13.13s "x8 . "\n";
printf ($format, "number","ceil_qtrs","ceil_xl(x,3)","ceil_xl(x,8)","ceil(x)","round(x,0)","round(x,1)","round(x,-2)");

foreach (@data) {
    printf ("%13.13s ",$_);
    printf ("%13d ",ceil_qtrs($_));
    printf ("%13d ",ceil_xl($_,3));
    printf ("%13d ",ceil_xl($_,8));
    printf ("%13d ",ceil($_));
    printf ("%13d ",round($_,0));
    printf ("%13d ",round($_,1));
    printf ("%13.3f ",round($_,-2));
    print "\n";
}