As stated by dragonchild, representation of floating point numbers is inexact. I added three lines to your program that show this.

#! /usr/bin/perl -w
 
use strict;
 
for( 0..9 ) {
    my $num0 = "1.$_";
    my $num1 = "1.0$_";
    my $num2 = "1.00$_";
#next three lines were added
    $num0 -= 1;
    $num1 -= 1;
    $num2 -= 1;
    printf "$num0 => %0.0f  $num1 => %0.1f  $num2 => %0.2f\n",
        $num0, $num1, $num2;
}

[download]

This produces the following output.

0 => 0  0 => 0.0  0 => 0.00
0.1 => 0  0.01 => 0.0  0.00099999999999989 => 0.00
0.2 => 0  0.02 => 0.0  0.002 => 0.00
0.3 => 0  0.03 => 0.0  0.00299999999999989 => 0.00
0.4 => 0  0.04 => 0.0  0.004 => 0.00
0.5 => 0  0.05 => 0.1  0.00499999999999989 => 0.00
0.6 => 1  0.0600000000000001 => 0.1  0.00600000000000001 => 0.01
0.7 => 1  0.0700000000000001 => 0.1  0.0069999999999999 => 0.01
0.8 => 1  0.0800000000000001 => 0.1  0.00800000000000001 => 0.01
0.9 => 1  0.0900000000000001 => 0.1  0.0089999999999999 => 0.01

[download]
---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';

[download]

In reply to Re: counter-intuitive sprintf behaviour by pfaut
in thread counter-intuitive sprintf behaviour by grinder

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