my $lange_zahl = 1.45548765;
my $kurze_zahl = sprintf "%.2f", $lange_zahl;
print $kurze_zahl;

print int($a/$laenge*100+0.5)/100;

$ perl -le 'for ($i = 0; $i < 0.101; $i += 0.005) { printf "%f :  %.2f <=> %f\n", $i, $i, int($i*100+0.5)/100};'
0.000000 :  0.00 <=> 0.000000
0.005000 :  0.01 <=> 0.010000
0.010000 :  0.01 <=> 0.010000
0.015000 :  0.01 <=> 0.020000
0.020000 :  0.02 <=> 0.020000
0.025000 :  0.03 <=> 0.030000
0.030000 :  0.03 <=> 0.030000
0.035000 :  0.04 <=> 0.040000
0.040000 :  0.04 <=> 0.040000
0.045000 :  0.04 <=> 0.050000
0.050000 :  0.05 <=> 0.050000
0.055000 :  0.05 <=> 0.050000
0.060000 :  0.06 <=> 0.060000
0.065000 :  0.06 <=> 0.060000
0.070000 :  0.07 <=> 0.070000
0.075000 :  0.07 <=> 0.080000
0.080000 :  0.08 <=> 0.080000
0.085000 :  0.09 <=> 0.090000
0.090000 :  0.09 <=> 0.090000
0.095000 :  0.10 <=> 0.100000
0.100000 :  0.10 <=> 0.100000

#!/usr/bin/perl

use strict;
use warnings;

my $s=2;
for (my $i = 0; $i <= (1/10**($s-1)); $i += (5/10**($s+1)))
{
 printf("%.".($s+1)."f  -->  sprintf:%.$s"."f  <>  round:%s   <>  int:%.$s"."f\n", 
        $i, $i, round($i,$s), int($i*(10**$s)+0.5)/(10**$s) );
}

sub round
{
 my $zahl=shift;
 my $stelle=shift;
 my $zz=$zahl+0;
 if($zz=~/^.+?\.\d{$stelle}/)
 {
  $zz=~s/^.+?\.\d{$stelle}/'0.'.('0'x$stelle)/e;
  $zahl+=$zz;
  $zahl=~s/^(.+?\.\d{$stelle}).*$/$1/;
 }
 $zahl=sprintf("%.$stelle"."f",$zahl);
 return $zahl;
}

C:\>perl -le "for ($i = 0; $i < 0.101; $i += 0.005) { printf qq~%.20f :  %.2f <=> %f\n~, $i, $i, int($i*100+0.5)/100};"
0.00000000000000000000 :  0.00 <=> 0.000000
0.00500000000000000010 :  0.01 <=> 0.010000
0.01000000000000000000 :  0.01 <=> 0.010000
0.01499999999999999900 :  0.01 <=> 0.020000
0.02000000000000000000 :  0.02 <=> 0.020000
0.02500000000000000100 :  0.03 <=> 0.030000
0.03000000000000000200 :  0.03 <=> 0.030000
0.03500000000000000300 :  0.04 <=> 0.040000
0.04000000000000000100 :  0.04 <=> 0.040000
0.04499999999999999800 :  0.04 <=> 0.050000
0.04999999999999999600 :  0.05 <=> 0.050000
0.05499999999999999300 :  0.05 <=> 0.050000
0.05999999999999999100 :  0.06 <=> 0.060000
0.06499999999999998800 :  0.06 <=> 0.060000
0.06999999999999999300 :  0.07 <=> 0.070000
0.07499999999999999700 :  0.07 <=> 0.080000
0.08000000000000000200 :  0.08 <=> 0.080000
0.08500000000000000600 :  0.09 <=> 0.090000
0.09000000000000001100 :  0.09 <=> 0.090000
0.09500000000000001500 :  0.10 <=> 0.100000
0.10000000000000002000 :  0.10 <=> 0.100000

0.000  -->  sprintf:0.00  <>  round:0.00  <>  int:0.00
0.005  -->  sprintf:0.01  <>  round:0.01  <>  int:0.01
0.010  -->  sprintf:0.01  <>  round:0.01  <>  int:0.01
0.015  -->  sprintf:0.01  <>  round:0.02  <>  int:0.02 <-- Falsch bei sprintf
0.020  -->  sprintf:0.02  <>  round:0.02  <>  int:0.02
0.025  -->  sprintf:0.03  <>  round:0.03  <>  int:0.03
0.030  -->  sprintf:0.03  <>  round:0.03  <>  int:0.03
0.035  -->  sprintf:0.04  <>  round:0.04  <>  int:0.04
0.040  -->  sprintf:0.04  <>  round:0.04  <>  int:0.04
0.045  -->  sprintf:0.04  <>  round:0.05  <>  int:0.05 <-- Falsch bei sprintf
0.050  -->  sprintf:0.05  <>  round:0.05  <>  int:0.05
0.055  -->  sprintf:0.05  <>  round:0.06  <>  int:0.05 <-- Falsch bei sprintf und int
0.060  -->  sprintf:0.06  <>  round:0.06  <>  int:0.06
0.065  -->  sprintf:0.06  <>  round:0.07  <>  int:0.06 <-- Falsch bei sprintf und int
0.070  -->  sprintf:0.07  <>  round:0.07  <>  int:0.07
0.075  -->  sprintf:0.07  <>  round:0.08  <>  int:0.08 <-- Falsch bei sprintf
0.080  -->  sprintf:0.08  <>  round:0.08  <>  int:0.08
0.085  -->  sprintf:0.09  <>  round:0.09  <>  int:0.09
0.090  -->  sprintf:0.09  <>  round:0.09  <>  int:0.09
0.095  -->  sprintf:0.10  <>  round:0.10  <>  int:0.10